Service Manual for 9600 CB & HWG - LAARS Heating Systems

Service Manual for

9600 CB & HWGHWG-M2 Series CB-M2 SeriesHWG-M2-250 CB-M2-250HWG-M2-200 CB-M2-200HWG-M2-175 CB-M2-175HWG-M2-150 CB-M2-150Hot Water Generator Condensing BoilerFor Natural or For Natural orPropane Gas Propane Gas

FOR YOUR SAFETY: This product must be installed and serviced by a professional service technician,qualified in hot water boiler installation and maintenance. Improper installation and/or operation couldcreate carbon monoxide gas in flue gases which could cause serious injury, property damage, or death.Improper installation and/or operation will void the warranty.

WARNINGIf the information in this manual is not followed exactly, a fire or explosion may resultcausing property damage, personal injury or loss of life.

Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this orany other appliance.

WHAT TO DO IF YOU SMELL GAS• Do not try to light any appliance.• Do not touch any electrical switch; do not use any phone in your building.• Immediately call your gas supplier from a nearby phone. Follow the gas supplier's

instructions.• If you cannot reach your gas supplier, call the fire department.

Installation and service must be performed by a qualified installer, service agency, or gassupplier.

Service Manual Document 2109

LAARS Heating Systems

TABLE OF CONTENTS

SECTION 1.General Information1A. Introduction ................................................... 31B. Start Up Procedures ..................................... 91C. Checkout Procedures ................................... 91D. Cleaning the Combustion Chamber Coil .... 101E. Diverting Valve ........................................... 101F. Safety Limit Switch ..................................... 101G. Boiler Control .............................................. 101H. Stack Switch ............................................... 111I. Igniter .......................................................... 111J. Transformer ................................................. 111K. Unit Pump ................................................... 111L. Blower ......................................................... 111M. Gas Valve ................................................... 111N. Time Delay Relay (TDR) .............................. 11

1O. Operating Control ........................................ 111P. Vent TCO .................................................... 121Q. Intake TCO .................................................. 121R. Thermal Cut-Out (TCO) ................................ 121S. Delayed Ignition ........................................... 121T. High Gas Consumption ............................... 121U. Noisy Operation .......................................... 121V. Short Cycling .............................................. 131W. Lock Outs (& Trip Outs) .............................. 131X. Routine De-Liming Procedure ...................... 141Y. Sequence of Operation ................................ 14

SECTION 2.Troubleshooting2A. Code ........................................................... 15

9600 CB & HWG Service Manual

SECTION 1.General Information

1A. IntroductionThe Heatmaker 9600 CB condensing boilers and

the Heatmaker 9600 HWG non-automatic circulatingtank water heaters have a dual heat exchanger (H-X)design. The primary H-X is a copper coil type whichoperates in a non-condensing mode. A secondarystainless steel H-X (economizer) surrounds the primaryH-X to condense water vapor from the flue gases andextract the maximum amount of heat from thecombustion process. Condensate from the economizerdrains into the bottom of the outer shroud of the boilersection and into the exhaust duct which provides forcondensate drainage.

Flow rates through the primary H-X arecontrolled by a thermostatic diverting valve whichdiverts water, as required, from the outlet of the

primary H-X back to its inlet so that the primary H-Xtemperature is always maintained above thecondensation temperature of the water vapor in the fluegases. A circulator is built into the unit to provideenough head to circulate water through the H-X’s andto a secondary heating loop or separate hot waterstorage tank.

The forced draft premixed combustion systemcontains a blower to provide air flow through the unit,the air inlet and exhaust piping. The cylindrical burneris provided with an air/gas mixture which is meteredthrough fixed orifices. A hot surface igniter (glow coil)is controlled by the Integrated Boiler Control whichalso controls the blower, circulator, and gas valve andprovides for burner flame safety.

The Heatmaker 9600 is designed to use 3" PVC*or ABS DWV pipe or PVC, ABS or CPVC schedule40 pipe for both air intake and flue material. Ventterminations are provided with the unit.* CB / HWG - M2- 250 flue material can only be ABS or CPVC.

(1) Diverting valve

(2) Circulator

(3) Mixer tube

(4) Exhaust

(5) Blower

(6) Gas valve

(7) Burner

(8) Economizer

(9) Combustion coil

(10) Cold water inlet

(11) Hot water outlet

(12) Heat exchanger drain

(13) Air vent

Figure 1. Heatmaker 9600 Assembly View.


(A) Cold Water Inlet From Tank or System

(B) Economizer Outlet (10°F Rise above inlet)

(C) Combustion Coil Inlet 130-140°F Typical

(D) Combustion Coil Outlet

(E) Hot Water Outlet To Tank or System 160 - 170°F Typical

(160° F THERMOSTAT)

Figure 2a. Water Flow through a Heatmaker 9600.HWG - Before S/N 394 - 068CB - Before S/N 795 - 0014

THERMOSTATICDIVERTING

VALVE

A PORTION OFHOT WATER

IS RECYCLEDTO MAINTAIN

COMBUSTIONCOIL INLET

TEMPERATUREAT 140°F (E)

(D)

(A)(B)

ECONOMIZER

COMBUSTIONCOIL


Legend1 Mixing Valve2 Internal Pump3 Mixer Tube4 Flue Outlet5 Combustion Fan6 Air Pressure Switch7 Burner8 Secondary Heat Exchanger9 Primary Heat Exchanger

10 Return (From Primary Loop)11 Gas Valve12 Flow (To Primary Loop) A Secondary Heat Exchanger Inlet B Secondary Heat Exchanger Outlet C Primary Heat Exchanger Inlet D Primary Heat Exchanger Outlet

Figure 2b. Water Flow through a Heatmaker 9600.HWG - After S/N 394 - 067CB - After S/N 795 - 0013


Figure 3. Air/Fuel Flow Through Heatmaker 9600.

43INTAKETERMINAL

50

WALLPLATE

AIRINTAKE

45

WALLPLATE

44

EXHAUSTTERMINAL

EXHAUST

AIRORIFICE

GASORIFICE

GAS1 COMBUSTION

COIL

2 ECONOMIZER

7 FLAMEHOLDER

46 EXHAUSTASSEMBLY

CONDENSATEREFERENCE PAGE 8 FOR PART NUMBERS


Figure 4. Cut Away View of Heatmaker 9600.

Figure 5. Control Box.


Figure 6. Control Components

* Specify Serial Number

# Part Description Part #1 Combustion Coil (Primary H-X) HWG 2400-086

Combustion Coil (Primary H-X) CB 2400-2842 Economizer Coil (Secondary H-X) 10-0783 Upper Head 10-0344 Inner Shroud 10-1125 Outer Shroud 10-124

6 Ignitor (w/Gasket) after s/n 391-126791-044 2400-286

6 Ignitor, before s/n 391-127 791-045 2400-2487 Burner (Flameholder) (w/Gaskets) 2400-082

Burner (w/Gaskets) (250 Series) 2400-3088 Upper Insulation (Blanket) 10-0489 Upper Insulation (Board) 10-05010 Lower Insulation (Board) 10-10611 Lower Insualtion (Blanket) 10-10812 Gasket, Igniter (1 req'd) 10-33213 Gasket, Burner (2 req'd) 10-33814 Gasket, Blower Inlet (1 req'd) 1-25415 Gasket, Blower Discharge (1 req'd) 10-324

Gasket, Blower Discharge (250 series) 11-06616 Blower Assembly (w/Gaskets) 2400-079

Blower Assembly (w/Gaskets) (250) 2400-31017 Orifice, Air *18 Orifice, Gas *19 Orifice Union 1-25220 Mixer Tube 10-252

Mixer Tube (250 Series) 11-01621 Air Duct Hose 1-458

Air Duct Hose (250 Series) 11-03822 Gas Valve Balance Line 2400-026*Not available separately - purchase orifice kit for type of gas

and input desired.

# Part Description Part #23 Jacket, Front Removeable 10-40224 Jacket, Top 10-406*25 Jacket, Bottom 10-01026 Control, Boiler Integrated 2400-22427 Transformer, 40 VA 2400-00628 Time Delay Relay 2400-06229 Wiring Harness 10-35430 Stack Switch 2400-11031 Operating Control 2400-05632 Safety Limit 2400-05533 Intake T.C.O. 2400-05834 Exhaust T.C.O. 2400-05835 T.C.O. 2400-02036 Gas Valve 2400-014

Gas Valve (250 Series) 2400-01537 Capacitor (Blower Start/Run) 2400-088

38

Pump, Grundfos UP 26-99-BF CB CB-250 HWG HWG-250

2400-3862400-3872400-3882400-389

39 Valve, Pressure Relief (150 PSI) 2400-094Valve, Pressure Relief (250 Series) 2400-095

40 Valve, Pressure Relief (125 PSI) 2400-096Valve, Pressure Relief (250 Series) 2400-097

41 Diverting Valve (Complete) 2400-001

42Thermostat (O-Ringsincluded)(160°F)before S/N 394-068 or 795-0014

2400-129

Thermostat (O-Ringsincluded)(140°F)before S/N 394-067 or 795-0013

2400-130

43 Terminal, Intake 2400-10244 Terminal, Exhaust 2400-10445 Flange, Wall, Vent Pipe 2400-10046 Exhaust Assembly 2400-390

Exhaust Assembly (250 Series) 2400-402

BLOWERASSEMBLYBLOCKEDFLUEDETECTOR

IGNITER ASSYGAS VALVEVENTTHERMALCUT OUTINTAKETHERMALCUT OUT

THERMALCUT OUT

16

30

6

36

34

33

35

32 HIGH LIMITSAFETY

SWITCH BOX

OPERATING LIMIT

CIRCULATOR PUMP

31

38

CONTROL BOXSUB-ASSY

HEATMAKER9600


1B. Start Up Procedures1. Make sure that the system is properly filled, com-

pletely purged of air and system valves are open.2. Open system gas cock(s) and gas control knob on

gas valve (if closed).3. Set the room thermostat, aquastat or storage tank

aquastat to call for heat.4. Turn on electrical power to the unit.5. The green light on the boiler control will light and

the internal circulator and blower will start. Aftera 15 second prepurge the igniter will come on for20 seconds and then the gas valve will open andignition will occur (for more details see“Sequence of Operation”).Note: Air in new gas lines may prevent ignition.

The boiler control will make a total of three attemptsfor ignition before lockout. To reset the control, switchoff the power switch for 10 seconds.

1C. Checkout Procedures1. Check burner input rate:

Allow burner to operate for at least 5 minutesbefore checking the input. On most LPinstallations it will be impossible to check theinput, however, checking combustion as in step 2below will guarantee proper burner operation. Tocheck the input (where possible) time the gasmeter to determine the time required for 4 cubicfeet of gas to pass through it. No other equipmentsupplied by the gas meter should be operatingwhen the timing is done. Table 1 can be used toconvert the time to input rate.Due to the effects of altitude and other minorvariances, it is possible that the input rate willdiffer slightly from the rating plate value.

2. Check combustion (see Figure 7).It is important to check the combustion with aCO2 or O2 tester (Bacharach for example) toensure maximum efficiency and reliability. Insert

the tester sample tube through the exhaustterminal and at least 6" (152mm) into the fluepipe. The unit must operate for 5 minutes beforetaking a sample. Take a sample and determine theCO2 or O2CO2 - 8% to 8.5% (natural gas)O2 - 7% to 6%CO2 - 9% to 9.8% (propane gas)If the burner is not operating in this range itshould be adjusted (see Burner Adjustment).

3. Burner AdjustmentThe Heatmaker 9600 CB & HWG burner systemis a pre-mixed forced combustion system. Outsideair is drawn through the air orifice (located in therubber hose in the air induction system) andmixed with the gas which is drawn in downstreamof the air orifice. All the air required for completecombustion comes into the system in this manner.The gas is metered through the gas orifice locatedin the gas orifice union.Adjusting the burner is limited to changing thegas orifice to achieve proper combustion. The airorifice cannot be altered and the gas valvepressure should not be changed.Before changing the gas orifice to adjust theburner, make the following checks:a. Gas valve supply pressure is between 4 and

14 in. W.C. (2.3 and 8.1 oz / in²)b. The differential pressure on the outlet side

of the gas valve (manifold pressure) isbetween -0.05 and -0.35 in. W.C.

If a. and b. are correct proceed as follows:When measuring CO2 (natural gas units),

readings below 8% generally indicate lean mixture (notenough gas). Reading above 9 1/4% indicate a richmixture (too much gas). Readings for LP units arehigher; below 9 1/4% is lean and above 10 3/4% isrich. If the readings are below the minimum values,install a larger gas orifice. If the readings are above themaximum value install a smaller orifice.

Figure 7. Checking Combustion.

Table 1. Time-to-Input Rate Conversion.

Time (4CF) Input Rate (Natural Gas)57 sec 252,600 BTU/hr

58 248,30059 244,00070 205,70071 202,80072 200,00074 194,60080 180,00082 175,60084 171,40094 153,20096 150,00098 146,900

EXHAUSTTERMINAL

COMBUSTIONTESTERSAMPLETUBE

1/4 IN. PER FT.

9600 CB


1D. Cleaning the CombustionChamber CoilNote: In normal operation this procedure is

seldom required. Should it prove necessary, thefollowing procedure is used to access the coil forcleaning.1. Turn off gas and electrical power to unit.2. Remove upper and lower front covers.3. Disconnect flue and combustion air pipes and

remove jacket top.4. Remove flue pipe assembly by disconnecting

from outer shroud.5. Remove mixer tube and blower assembly.6. Remove igniter and burner (flameholder).7. Fit mask and eye protection.8. Fit mask and eye protection.9. Locate vacuum hose at flue outlet of outer

shroud and start vacuum cleaner.10. Bend air chuck extension 90° at a point about

2-3" from end.

Insert air chuck extension through burner hole inupper head. Direct end of extension toward fins ofheat exchanger and blow off accumulated residue.Methodically move up and down and completelyaround the heat exchanger. After completion of this,remove the extension from the burner hole and inspectthe condition of the heat exchanger with a flashlightand inspection mirror. If there are areas on the heatexchanger that still have some residue, repeat theprocess on those areas until the heat exchanger isclean.

Figure 8. Disassembly.

After the heat exchanger is clean, remove thevacuum cleaner from the outer shroud flue outlet andstop vacuum cleaner.

Carefully inspect the seal between the outershroud and the upper head and the joint in the outershroud. If there is any evidence of leakage from eitherof these joints, clean off the silicone in that area andprepare the surface for resealing. Commerciallyavailable oven cleane is an appropriate cleaning agent.Reseal the affected areas witih silicone, reassemble allparts in the reverse order and check boiler operation.

1E. Diverting ValveThe diverting valve is a thermostatically

controlled device which keeps the primary heatexchanger (H-X) from operating in the condensingmode. When return water from the storage tank or thesystem is below 130°F (54°C) the diverting valverecycles a portion of the outlet water from the primaryH-X back to the primary H-X inlet so that theminimum temperature required to preventcondensation on the primary H-X is maintained at160°F (71°C). The thermostat element is similar tothose used in large industrial engines.

To change the thermostatic element, valve offthe unit and turn off electrical power. Open boilerdrain to relieve pressure and close again. Remove thecap screws (3) and remove top of valve. Remove andreplace the element (with barrel up), spring and sealingdisc. Place O-ring under valve top and replace top.Secure with cap screws and tighten. Turn on valvesand bleed air from the top of the diverting valve. Turnon electrical power and restart unit.

1F. Safety Limit SwitchThe Safety Limit Switch has a fixed set point of

245ºF (118°C). It has a manual reset button whichmay be reset at temperatures below 240ºF (116°C).

To replace the switch, shut off the 120 voltpower and valve off the unit. Drain a gallon of waterfrom the boiler and remove the 3/8 NPTM fittingwhich seals the capillary. Remove the two screwswhich hold the switch to the side panel, remove theswitch and unplug the switch wires. Install thereplacement in the reverse order, open isolation valvesand bleed air from the diverting valve petcock. Switchon 120 volt power and restart unit.

1G. Boiler ControlThe boiler control controls the combustion

process, the gas valve, the igniter, the blower, and theunit pump.

It provides blower prepurge as well as burnerflame sensing. When replacing the boiler control allplugs are color coded and it is not possible to miswirethe control. See sequence of operation for operatingdetails.

ECONOMIZERRETAINERS (4)

OUTER SHROUDCLAMPS (4)

COLD WATERINLET

PLASTIC FLANGE,(4) NUTS

COMBUSTIONCOIL

MANIFOLDS

ECONOMIZEROUTLET

ECONOMIZER

INNERSHROUD

MANIFOLDDRAIN


1H. Stack SwitchThe Stack Switch is a normally open single pole

switch which is operated by the pressure differenceacross the air orifice. It is set to close when a staticpressure difference of 1 in. W.C. is generated by thecombustion air blower. Its function is to prove airflowand to inhibit burner operation in the event of fluestoppage. The switch is wired directly to the boilercontrol. It is located on the inside of the jacket backpanel.

1I. IgniterThe Igniter is a “glow bar” type silicone carbide

unit. It is energized whenever there is a call for heatand the red “IGNITER” light on the boiler control islit. After the igniter is switched off and boiler continuesto run, the igniter functions as a flame sensor for theboiler control.

If the igniter fails and must be replaced, alwaysinstall a new igniter gasket with the replacementigniter.

1J. TransformerThe control transformer accepts 120 VAC power

and provides 40 VA of 24 VAC power for the boilercontrol only. It is not capable of supplying controlpower for external devices such as zone valves. Theymust have their own separate power supply.

1K. Unit PumpThe unit pump is a wetted rotor type pump which

operates whenever there is a call for heat or hotwater.

If a pump change is required for any reason,valve off the boiler and drain approximately 1 or 2gallons of water (3.79 to 7.58L) from the unit throughthe drain under the chamber. Drain is accessed byremoving lower front panel. Turn off the maindisconnect switch and unplug the pump wires, removethe pump motor. The pump housing need not beremoved. The replacement pump motor should beinstalled in the reverse order from which the old pumpmotor was removed. After filling the system, be sure tobleed air from the diverting valve petcock.

1L. BlowerThe combustion air blower is a high head

centrifugal blower,. It is designed to provide about 4"W.C. of suction at 43 CFM. This performance isnecessary to operate the gas valve reliably, toovercome induction system friction losses and toeliminate any sensitivity to wind striking the ventterminal. It is powered by a 120 volt motor whichdraws about 1.65 amps at rated load. It is controlledby the boiler control. Whenever there is a call for heatand 30 seconds after, the blower should be energized.If a blower change is required, turn off the 120 volt

power and unplug the power wires from the blowermotor. Disconnect intake exhaust vents and remove topjacket. Remove the six bolts and nuts from the blowerdischarge flange and the four nuts from the blowerinlet flange. The blower may now be deflected enoughto permit its removal. Replace the new blower usingnew gaskets, in the reverse order from which the oldblower was removed. The four Inlet flange nuts,however, should only be finger tight initially and thentightened with a wrench after all other operations havebeen completed. The combustion should be checked forcorrect air-fueled ration whenever the blower isreplaced (see Burner Adjustment.)

1M. Gas ValveThe gas valve is a solenoid operated, negative

pressure regulated valve. The outlet pressure isregulated at minus .2 inches W.C. It is designed tooperate with supply pressures of 4-14 inches W.C.Within that range of supply pressures, the regulateddischarge pressure may vary from minus .05 to minus.35 inches W.C. The regulator is not adjustable and theeffect of this variation in discharge pressure is notsignificant. Because of the fixed regulator setting, gasflow must only be adjusted by changing the gas orifice.

To remove the gas valve, shut off the 120 voltpower and the master gas cock in gas line, loosen thenut on the gas orifice union and remove the orificeunion plus piping to the gas valve. Disconnect thewires from the gas valve. the valve may now beunscrewed from the inlet piping. It may be necessaryto deflect the inlet piping somewhat in order to clearthe boiler jacket. After the valve has been removed,replace with a new valve in the reverse order in whichthe old valve was removed. Do not overtighten thefittings into the valve body as this may cause damageto the valve.

1N. Time Delay Relay(TDR)The time Delay Relay controls the unit pump and

keeps it operating for approximately one minute afterthe blower post purge stops. This function dries out themoisture in the chamber to prevent corrosion. Controlvoltage on the TDR is 24 volts from the limit circuit.The contacts to supply pump power are 120 VAC.They open one minute after the 24 volt control voltageis interrupted. Turn off disconnect switch beforechanging TDR.

1O. Operating ControlThe operating control functions as a high limit to

prevent boiler outlet temperatures from exceeding210°F (99°C) on CBs and 185°F (85°C) on HWGsduring periods of low load or high return watertemperatures. It will reset automatically when theboiler temperature drops to 170°F (77°C). To replaceimmersion type, valve off boiler and drain about a


gallon of water from it. Turn off electrical power anddisconnect wires from operating control. Removeoperating control from diverting valve body andreplace with new control. Connect wires to control andopen isolation valves. Bleed air from the divertingvalve petcock, turn on electrical power and restartboiler. The strap on type may be changed withoutdraining.

1P. Vent TCOThe vent TCO is a normally closed temperature

switch which functions to shutdown the burner if fluegas temperatures exceed 180 - 200ºF (82-93°C). It ismounted on the 3" (76mm) exhaust pipe inside the unitbetween the top of the lower panel and the top. Switchoff electrical power when changing this safety.

1Q. Intake TCOThe intake TCO is a temperature switch with

normally closed contacts which open on a temperaturerise at 180°F (82°C). It is identical to the vent TCOand functions to interrupt power to the gas valve if themixer tube temperature exceeds 180°F (82°C). It ismounted on the mixer tube about 3" (76mm) aboveburner flange. Switch off electrical power whenchanging this safety also.

1R. Thermal Cut-Out (TCO)The thermal cut-out is a probe type temperature

switch with normally closed contacts which open on atemperature rise at 450°F (232°C). It is located on theright side of the upper head with the probe extendingdown into the exhaust passage between the boiler coiland the economizer coil. It functions to interrupt powerto the gas valve if the flue gas temperatures exceed450°F (232°C) for any reason. Switch off electricalpower when replacing.

1S. Delayed IgnitionPossible Causes - Time of occurrence

1. High lockups on LP - occurs on start up.2. Gas valve regulation problem - occurs on start up.3. Defective burner (flameholder) - occurs primarily

on burner shutdown4. Natural gas orifice in LP unit - occurs on startup

High lock up pressures on LP fuel systems arethe most common cause of delayed ignitions onHeatmaker boilers. The high LP supply pressureresults from improper second stage regulator selectionor a faulty regulator.

It can be detected by measuring the gas supplypressure to the unit at the inlet pressure tap on the gasvalve. Use a water manometer or pressure gage with ascale reading of at least 25 in. W.C. or 1 oz/in 2.Install the pressure tap in the 1/8 NPTF plugged port

located above the gas inlet port on the gas valve. Thegas supply to the boiler must be shut off before makingthis connection. The Heatmaker boiler is designed tooperate with supply pressures of 4-14 in. W.C. (8.1 oz/in2) with the boiler not operating it is likely that this isthe cause of the delayed ignition. Lock up pressuresmust be measured when the boiler is not operating andpreferably immediately after boiler shutdown.

Gas valve regulation problems can also causedelayed ignitions. To detect gas valve regulationproblems it is necessary to have an inclined manometeror a Magnehelic pressure gage. The normal gas valveregulator setting is -0.2 IN. W.C. This should happensmoothly without allowing pressure spikes positivewhen the solenoid opens then the gas valve regulator isfaulty and may be the cause of the delayed ignition.

A defective burner (flameholder) can cause adelayed ignition however not often. If the gas supplypressure and the gas valve are functioning properly andthe air and gas orifices are correct the burner should beinspected. To inspect, remove the mixer tube and theburner will lift out of the top of the chamber. Thereshould be no perforations other than the punched holes.Replace in the reverse order with new gaskets.

1T. High Gas ConsumptionImproper burner operation caused by incorrect

air/fuel ratio (CO2 or high O2 out of the specifiedrange) will cause high gas consumption. It is mostnoticeable on LP fired units with low CO2 or high O2,however, units operating on LP or natural gas withincorrect air/fuel ratios will not provide their bestefficiency. If no combustion analyzing equipment(CO2 or O2) is available, an indication of the air/fuelration can be gotten by briefly sniffing the flue gases.When running properly the Heatmaker’s flue gasesshould have no smell. If they have a strong piercingsmell, the gas orifice is probably too small. Do notattempt to do re-orificing without an O2 or CO2 kit.

1U. Noisy OperationThere are two principal sources of excessive

noise.1. Combustion2. Boiling (kettling or knocking)

Combustion noise can occur when the burner isoperating with a very rich or a very lean mixture. Arich mixture (high CO2 or low O2 - gas orifice toolarge) will cause a high pitched noise that is loudest atthe vent terminal. A lean mixture (low CO2 or high O2- gas orifice too small) will cause a very unevenrumbly noise and may sometimes be associated with anuisance lockout situation and a strong piercing odorat the vent terminal. Both noises may be eliminated byproper burner adjustment (see Burner Adjustment).


Boiling noises can occur because of air in thesecondary loop of a heating system (9600 CBapplications) or because of pump failures in either the9600 CB or 9600 HWG.

Another boiling noise which occurs primarily on9600 HWG units can result from liming of the primaryheat exchanger. This noise is more pronounced andmay occur at any temperature. If the pump appears tobe operating properly and the unit continues to runnormally except for the knocking sound then limingshould be suspected and the unit should be de-limedaccording to the “Routine De-liming Procedure”. If theknocking is very sever, de-liming may not stop thenoise and the primary heat exchanger will need to bereplaced.

The knocking sound may also exist on 9600 CBand 9600 HWG units for a very short time followed bya safety limit trip out. The generally results from totalpump failure (impeller sheared off or motor notrunning at all).

1V. Short CyclingThere are two different types of short cycling

1. System related2. Combustion related

The most common cause of system related shortcycling is boiler oversizing (9600 CB). Because the9600 CB is a low mass boiler with high output it willshort cycle if system load or water flow are insufficientto accept all of its output. This situation may alsooccur with a properly sized boiler when it is installed ina zoned system and one or more of the zones are verysmall. If a small zone causes the problem then it maybe necessary to only allow that zone tooperate when another zone is calling.This can be accomplished withoutrepiping in a zone valve system by disconnection theend switch wire fromthe zone valve which controls the small zone(s). If theboiler is oversized, cycletime may be reduced by reducing theboiler input. An orifice kit is available to reduce inputfrom 200,00 BTU/HR to 150,000 BTU/HR or175,000 BTU/HR.

System related short cycling can also occur on9600 HWG Units. It results from very high aquastatsettings on the storage tank. Settings higher than 160°-170°F (71°-77°C) should be suspected of being thecause. Many times tank aquastats are set high tocompensate for an undersized system. If they are settoo high and the unit short cycles then the output fromthe system will actually be reduced.

Combustion related short cycling occurs when theburner is incorrectly adjusted. Lean mixtures (lowCO2 or high O2) cause the boiler control to lose theflame signal. The control then causes a restart and if

the flame signal is sensed on the restart then theburner will operate again. The intermittent sending andlosing of the flame signal by the boiler control causes itto short cycle the burner. If combustion related shortcycling is suspected refer to “Checking Combustion”.

1W. Lock Outs (& Trip Outs)The principal cause of nuisance lockouts are

1. moisture in the combustion chamber2. poor combustion3. igniter failure4. short cycling

Safety limit trip outs are generally caused by lowflow or recirculation in the primary heat exchanger.

Moisture in the combustion chamber can becaused by a failure of the thermostatic element in thediverting valve. If the element fails in the full openposition, it will cause the primary heat exchanger tooperate in the condensing mode by allowing low outlettemperatures. This condition should be suspected ifboiler outlet temperatures are consistently below 160°F(71°C). The moisture causes a loss in flame sensingand the boiler control will shut the unit down.

Poor combustion may cause a boiler controllockout by transmitting a very weak flame signal to theboiler control. The boiler control senses a flame usingthe flame recertification principle. This principleutilizes the fact that a flame is not only conductive butit converts AC voltages to DC. The igniter whichbecomes a flame sensor after it is deenergized as anigniter has an AC voltage applied to it by the control.If a flame exists the AC is converted to DC andconducted to ground through the burner or the primaryheat exchanger.

Since natural gas or LP are neither conductivenor capable or rectifying an AC voltage to DC, theburner control can determine if a flame exists or not bythe presence of DC or AC current. Poor combustioncan make this decision difficult because of poorconductivity. There are many causes for poorcombustion. Incorrect burner adjustment is the mostobvious, however, a blocked condensate drain or animproper flue installation can cause a restriction in theflue which will cause poor combustion. If there is arestriction in the flue from condensate or rain waterbuildup a gurgling sound can be heard at the ventterminal.

Igniter failure may also cause a nuisance lockoutbut not very often. If igniter failure is the cause thereprobably will be an indication of overheating in theigniter area resulting from gasket failure.

Short cycling may cause either burner controllockouts or tripouts of the manual reset safety limit.Generally it will be tripouts, however, in someinstances a lockout will occur and the boiler control


will require resetting. If a lockout occurs for any of thereasons stated in this section the “VALVE/FLAME”light on the boiler control will flash.

Tripouts of the manual reset safety limit can becaused by a failure of the thermostat in the divertingvalve, short cycling or a calibration change in thesafety limit. If the thermostat in the diverting valvefails in the closed position, all of the water leaving theoutlet of the primary heat exchanger will berecirculated back to the inlet and the temperature willrise rapidly. This rapid temperature rise may cause thesafety limit to trip before the operating control senseshigh temperature. Short cycling may cause a tripout inthe same manner. A calibration shift in the safety limitmay also cause it to trip out. If the temperature of thewater leaving the unit is well below 240°F (116°C) andthe recirculation line from the diverting valve to thepump inlet is not extremely hot the safety limit may bedefective. These same conditions may also indicate apump failure, however, knocking generally occurswhen a pump fails.

1X. Routine De-Liming ProcedureROUTINE DE-LIMING PROCEDURE in hard

water areas. This should be done on a regularlyscheduled basis.1. Close the gas cock or manual gas shutoff (see

Figure 9) and shut off the main disconnect switch.2. Isolate the HeatMaker 9600 HWG unit from the

system by closing the shutoff valves. If recirc.lines are piped, isolate the return system fromwater heater.

3. Remove the lower front panel from the waterheater and connect a hose to the drain fitting.(Located under the cylindrical chamber.) Relievepressure at drain.

4. Connect a hose to the drain (provided byinstaller) on the cold (return) side piping to theappliance.

5. Remove cover from thermostatic valve andremove thermostat. Wrap tape around / overcutaway sections in the cover and replace allparts except thermostat. Reinstall valve cover andtighten bolts.

6. Fill the water heater combustion coil withdeliming solution from the hose connected underboiler coil assy. until it exits from upper hose. Asmall pump should be used to do the filling froma plastic container. The upper hose should thenbe placed in this container and the pump shouldrun until the circulator solution is no longerfoamy.

7. Shut off pump and disconnect from hose.Carefully drain solution from hoses and connectcity water to lower hose to flush combustion coil.Flush for approximately 5 minutes with citywater.

8. Remove hoses, close drain cock, close drain oncold / return, and replace lower front panel .

9. Remove cover from thermostatic valve andremove tape. Replace thermostat, spring brassring and valve cover, and tighten bolts.

10. Open shut off valves and purge air from petcockat top of thermostatic valve cover.

11. Re-open gas supply and turn on main disconnectswitch to return heater to service.

1Y. Sequence of OperationOn a call for heat from the room thermostat on

9600 CB series boilers, or the tank aquastat on 9600HWG series, the boiler control is energized through thecontrol, the vent TCO and the safety limit. It energizesthe pump, checks to ensure that the stack switchcontacts close and the red “PURGE” light lights. Thepump and blower continue to run and for 15 secondsthe red “PURGE” light goes out, the red “igniter” lightlights and the igniter heats for 20 seconds. At the endof the 20 seconds, the red “VALVE/FLAME’ light islit and the gas valve is energized. For 2 seconds thevalve and igniter are energized and burner will ignite.Following this the igniter is deenergized and the red“IGNITER” light goes out and the pump and blowercontinue to run and the burner operator under thesupervision of the boiler control. If for any reason thefull sequence is completed and the burner doesn’tignite, the sequence will be repeated after a blower“on” time of 45 seconds (30 seconds post purge and 15seconds prepurge for the next cycle). During this partof the sequence, the igniter remains on for 30 secondsand the balance of the sequence is unchanged. If noignition occurs again, a third cycle will follow with thesame sequence as the second. After the third “trial forignition”, if the burner does not ignite, the system will“lock out” (valve/flame light flashing) and reset canonly be accomplished by momentarily switching thepower off. At the end of the heating cycle, after the gasvalve is deenergized, the blower will continue to runfor a 30 second post purge and the pump will run forabout another minute. If normal burner operationduring a heating cycle is interrupted by any of the limitcontrols the blower will continue to operate for a 30second post purge and the pump continues to operateuntil the call for heat is satisfied.


SECTION 2.Troubleshooting(Detailed Flow Charts on Page 16-22)

If the burner “locks out” for any reason, thecause of failure will be displayed by the flashing of oneof the lights.2A. Code

GREEN “POWER” - Light flashing - controlfailure, no light, no power

RED “PURGE” - Light flashing - blower orstack switch failure or possible flue blockage.

RED “VALVE/FLAME” - Light flashing - valve,igniter or flame sense failure (combustion relatedproblem).

Normal Operation.

Note: If the stack switch contacts are closed forany reason when the blower isn’t operating, a sequencewill not occur and after 45 seconds the control will“lock out” and the “PURGE” light will flash. If thestack switch contacts are open and do not close duringpurge period, after 5 minutes the control will lock outand the “PURGE” light will flash. If the boiler does notoperate, the green “POWER” light is on and noindicator lights are flashing, check for an open ventTCO, operating control or safety limit switch. Foradditional troubleshooting information refer to thetrouble shooting flow charts on the pages that follow.

POW

ERON TH

ERM

OSTA

T

CALL

FO

R HE

AT

THER

MOS

TAT

CALL

FO

RHE

AT E

NDS

STAN

DBY

PROV

E NO

AI

RFLO

WPR

OVE

AI

RFLO

W

PREP

URGE

WAR

MUP

TRIA

L FOR

IG

NITI

ON

RUN

POST

P

URGE

STAN

DBY

45SECMAX

5MINMAX

15SEC

20SEC

8SEC

30SEC

POWER LED

AQUASTAT/AUXILIARYLIMITS

CIRCULATOR

AIR PROVING SWITCH

COMBUSTIONAIR BLOWER

PURGE LED

IGNITER

PROOF OF FLAME

IGNITER LED

GAS CONTROL

VALVE/FLAME LED

1

3

3

CLOSED

CLOSEDOPEN

2

2 SECAP

1 SEC

1 POWER LED BLINKS ONCE WHEN 24V POWER IS APPLIED AND WHEN THE THERMOSTAT CALLS FOR HEAT.

2 ON AS LONG AS CONTROL IS POWERED AND OPERATING PROPERLY.

3 IF EITHER SWITCH OPENS DURING THE RUN CYCLE, BURNER WILL STOP, FOLLOWED BY POSTPURGE.CIRCULATOR WILL RUN AS LONG AS THERMOSTAT IS CALLING FOR HEAT. BURNER IGNITION SEQUENCEWILL RESTART IF SWITCH CLOSES.


PURGE - SEE PAGE 18VALVE/FLAME SEE PAGE 21

1. LIMIT CIRCUIT OPENSEE PAGE 17

2. NO CALL FOR HEAT/HOT WATER

REPLACE BOILERCONTROL2400-224

REPLACE TRANSFORMERAND RUN BOILERTHROUGH A FEW CYCLES

HAVE QUALIFIEDELECTRICIANREPAIR FAULT INWIRING TO THEBOILER

CHECK FOR VOLTAGE (24VAC) BETWEEN YELLOWWIRES AT BACK OF "VAC24XFMR" CONNECTOR ONBOILER CONTROL

GREEN LIGHT COMES ON 1. IS SERVICE SWITCH ON?2. IS CIRCUIT ON?3. ARE FUSES OR CIRCUIT

BREAKER OK?

CORRECT ANDRECYCLE BOILERRUN THROUGH AFEW CYCLES

CHECK FOR VOLTAGE(120 VAC) BETWEENBLACK AND WHITEWIRES AT BACK OF "120VAC" CONNECTOR ONBOILER CONTROL

DID BOILER RUN THROUGH ACOMPLETE CYCLE AS DE-SCRIBED IN SEQUENCE OFEVENTS PAGE 20

TEST LIMITCIRCUITPAGE 17

PUMP OPERATES(120 V TO PUMP)

REPLACE2400-224

CHECKSTACKSWITCH

GENERAL TROUBLE SHOOTING

YES NO

YES NO

NOYES

OK NO

NO 0 VOLTS

120VOLTS

0VOLTS

24 VOLTS

*POOR SWITCH CONTACT ON RELAYS, ZONE VALVES, OR THERMOSTATS CAN CAUSE A FLASHINGGREEN LIGHT ON JOHNSON CONTROLS G856DBG - 5201.

AFTER 5 MINUTES ARE ANYRED LIGHTS FLASHING

YES

YES NO

REPLACE

DEFECTIVE

RESET BOILER CONTROL BY SWITCHING OFFPOWER AT SIDE OF UNIT FOR 15 SECONDS

REPLACE BOILERCONTROL 2400-224

REFER TO FLOWCHART FOR SPECIFICPROBLEM

OK

YES

CORRECT

OPEN


1

2

3

4

5

6

7

8

9

RED

RED

CN6"CONTROL"

1. SWITCH BOILER OFF2. UNPLUG 9 PIN "CONTROL" PLUG3. CHECK FOR CONTINUITY AT BACK OF

"CONTROL" PLUG BETWEEN RED WIRES(BOILER TEMP BELOW 170F)

LIMIT CIRCUIT APPEARS OK -RECYCLE BOILER A FEW TIMES AFTERPLUGGING IN "CONTROL" PLUG

CHECK FOR CONTINUITY ACCROSSOPERATING CONTROL CONTACTS REPLACE SAFETY LIMIT

REPLACE OPERATINGCONTROL

ALL LIMITS OK.BOILER SHOULD CYCLE PROPERLY ONA CALL FOR HEAT OR HOT WATER

PUSH SAFETY LIMIT RESETBUTTON* BUTTON CLICKS

(0 OHMS ON LOWOHM SCALE)

CONTINUITY

CONTINUITY

CONTINUITY

NO CONTINUITY( OHMS)

NO CONTINUITY

TESTING LIMIT CIRCUIT(YOU MUST COMPLETE PAGE 16 FIRST)

NOTE: AFTER COMPLETEING LIMIT CIRCUIT TESTING, PLUG IN CONTROL PLUG AND RECYCLEBOILER A FEW TIMES. IF BOILER A BOILER DOES NOT RECYCLE CONNECT A JUMPER TEMPORARILYBETWEEN THE RED WIRES. IF BOILER STARTS REMOVE JUMPER AND TEMPORARILY JUMP EACHSAFETY CONTROL UNTIL THE DEFECTIVE CONTROL IS LOCATED. NEVER LEAVE A SAFETY CONTROLJUMPED.* CHECK BOILER PUMP IF SAFETY LIMIT HAS TRIPPED.

CONTINUITY CHECK FORCONTINUITY ACROSSVENT (EXHAUST) TCO

YES NO

NO OVERHEAT CONDITIONHAS OCCURRED

CHECK FOR CONTINUITY ACCROSSSAFETY LIMIT CONTACTS

NO CONTINUITY

REPLACE VENT(EXHAUST) TCO

NOCONTINUITY


RESET BOILER CONTROL BYSWITCHING POWER OF FOR 15SECONDS AND THEN ON AGAIN

WITH A CALL FOR HEAT / HOTWATER AFTER APPROX. TWOSECONDS GREEN LIGHT COMESON AND BLOWER STARTS

AFTER FIVE MINUTES RED"PURGE" LIGHT FLASHES

STACK SWITCH CONTACTSNOT CLOSING CHECK FORFLUE BLOCKAGE (SNOW,LEAVES ETC.) AGAINSTVENT TERMINAL

CYCLE BOILER MANY TIMESTO TRY TO CREATE AMALFUNCTION

CLEAR BLOCKAGE ANDRECYCLE BOILER

CHECK STACK SWITCH

BLOCKAGEEXISTS NO

BLOCKAGE

NOYES

YES NO

RED "PURGE" LIGHT FLASHING(YOU MUST COMPLETE PAGE 16 FIRST)

AFTER 45 SECONDS RED"PURGE" LIGHT FLASHES

AFTER 5 MINSRED "PURGE"LITE FLASHES

NO

CHECK BLOWER PAGE 20

YES

SHUT OFF POWER, DISCONNECTWIRES TO STACK SWITCH, TURNON POWER - AFTER TWO SEC-ONDS BLOWER STARTS

RECONNECT STACKSWITCH WIRES.CHECK BLOWER

CHECK STACK SWITCH

YES NO

YES



1. SWITCH OFF BOILER SWITCH2. REMOVE BOTH TUBES FROM

STACK SWITCH AND DISCONNECTELECTRICAL WIRES3. CHECK FOR CONTINUITY ACROSSSWITCH TERMINALS

1. ATTACH TUBES DISCONNECTEDFROM STACK SWITCH TO U-TUBEMANOMETER

2. SWITCH ON BOILER TO OPERATEBLOWER

3. MANOMETER INDICATES 1.5" W.C.OR GREATER

REPLACE STACKSWITCH P/N 2400-110

RECONNECT STACK SWITCHTUBES AND CHECK FORCONTINUITY BETWEEN STACKSWITCH TERMINALS WITHBLOWER OPERATING

CHECK FOR VENT OBSTRUCTIONS

CLEAR OBSTRUCTIONS &RECONNECT TUBES & ELEC-TRICAL WIRES TO STACKSWITCH - START BOILER &RUN THROUGH A FEWCYCLES

STACK SWITCH OK

REPLACE STACKSWITCH P/N 2400-110

CONTINUITY(0 OHMS)


CONTINUITY(0 OHMS)

OBSTRUCTEDCLEAR

NO

YES

CHECK BLOWERPAGE 20

NOTE: CHECK TUBES ON STACK SWITCH FOR PROPER CONNECTIONSTUBE CONNECTION CLOSEST TO YOU SHOULD CONNECT TO BARBED TEE FITTING ABOVE AIR ORIFICE.

CHECKING STACK SWITCH(YOU MUST COMPLETE PAGE 16 FIRST)


WITH A CALL FOR HEAT RESETBOILER CONTROL BY SWITCHINGOFF BOILER SWITCH FOR 15 SECS.

AFTER TWO SECONDS GREENPOWER LIGHT COMES ON.

REFER TO GENERAL TROUBLESHOOTING SECTION PAGE 16

CONNECT MANOMETER TO "PRESSURE TAP" ONGAS VALVE - PRESSURE DURING BLOWEROPERATION WITHOUT GASFLOW (VALVE/FLAMELIGHT NOT LIT) IS - 4 IN. W.C.

CHECK FOR VOLTAGE 120 VACAT BLOWER WIRE CONNECTOR(WITHIN 5 MINS. AFTER GREENLIGHT)

BLOWER O.K. REPLACE BLOWER

BLOWER STARTS

YES

YES NO

YES

NO

NO

CHECKING BLOWER(YOU MUST COMPLETE PAGE 16 FIRST)

REPLACE BLOWER

0 VOLTS 120 VAC

CHECK TT, LIMITS,STACK SWITCH

REPLACE BOILERCONTROL 2400-224

REFER TO PAGE 17REFER TO PAGE 19

OK OPEN


RESET BOILER BY SWITCHING POWER OFF FOR15 SECONDS - WHEN "VALVE/FLAME" LITE LIGHTSIS THERE 24 VAC BETWEEN ORANGE AND YEL-LOW WIRES ON GAS VALVE AND/OR DOES GASVALVE CLICK?

TURN ON VALVES, FILL LP TANK ON LP UNIT- IF REQ'D - RESET BOILER BY SWITCHINGPOWER OFF FOR 15 SECONDS. RUNTHROUGH TWO TO THREE CYCLES

CHECK TCO AND INTAKE TCO FOR CONTINUITYDOES BURNER IGNITE ANDAPPEAR TO RUN PROPERLY?

NUISANCE LOCKOUT CAUSED FLASHINGLITE - CHECK COMBUSTION

CHECK IGNITER-IGNITER OK?

CHECK FOR GAS FLOW- IS METER MOVING?

REPLACEIGNITER

REPLACE INTEGRATED BOILER CONTROL P/N 2400-224

INSTALLCORRECTORIFICES

BOILER CYCLES THROUGH THREE CYCLES AFTERRESETTING AND "VALVE/FLAME" LITE FLASHES

CHECK GAS AND AIR ORIFICEFOR PROPER SIZE

REPLACE GAS VALVE

ARE GAS VALVES AND GAS METER TURNED ON.IS THERE GAS IN LP TANK (LP UNITS).

YES

YES

YES

YES

YES

NO

NO

NO

INCORRECT CORRECT

RED "VALVE/FLAME" LIGHT FLASHING(YOU MUST COMPLETE PAGE 16 FIRST)

NO

NO

REPLACEDEFECTIVE

TCO

CHECKWIRES TO

GAS VALVE

CONTINUITY(0 OHMS)


REPLACEINTEGRATED

BOILERCONTROL P/

N 2400-224

CORRECTWIRING

OK

FAULTY


YES

CHECKING INTERNAL PUMP(YOU MUST COMPLETE PAGE 16 FIRST)

SWITCH POWER ON, GREENPOWER LIGHT LIGHTS

CALL FOR HEAT EXISTS(THERE IS 24 VOLTS ON

PINS #7 & #9 ON'CONTROL' PLUG - CN6)

THERE IS 120 VAC AT'CIRCULATOR' PLUG-CN5

TURN UP T'STAT OR AQUASTAT ORCORRECT STAT PROBLEM

NOYES

NOYES

SEE TROUBLE SHOOTINGCHART PAGE 16

THERE IS 120 VAC AT PUMPREPLACE BOILERCONTROL P/N 2400-224

NO

CORRECT WIRING BETWEENPUMP AND CONTROL BOX

NO

MOTOR PUMP RUNS

YESNO

REPLACE PUMP PUMP IS PUMPING

YES

PUMP OK PUMP IS AIR BOUND OR IMPELLER HASBROKEN; ELIMINATE AIR OR REPLACE PUMP

NO

YES


Figure 9. 9600 Ladder Diagram.

Figure 10. 9600 Wiring Diagram.

CautionLabel all wires prior to disconnection when servicing controls. Wiring errors cancause improper and dangerous operation. Verify proper operation after servicing!

Quick Reference Trouble Shooter

A. SHORT CYCLING:1. 9600 HWG - tank aquastat set too high2. 9600 CB and 9600 HWG - Units shuts down before reaching limit. Continuously restarts

without resettinga. Limit out of calibrationb. Wrong air/gas orifices for input or fuel (refer to HeatMaker 9600 gas orifice chart ONLY)c. Thermostat heat anticipator set below 0.9 amps. (9600 CB only).

3. 9600 CB - boiler oversized for total load or small zone.

B. HEATMAKER 9600 OVERHEATS QUICKLY OR KNOCKS DURING OPERATION:Boiling noise in combustion chamber.1. Air in combustion coil or in pump: Purge system2. Pump failure or control failure.3. 9600 HWG lime buildup in primary heat exchanger.4. 9600 HWG restriction in storage tank piping.5. Defective diverting valve element.6. 9600 CB restriction in supply/return piping.

C. DELAYED IGNITION: Unit starts or stops with a “pop”.1. Wrong gas orifice for fuel or air orifice size.2. LP - Gas regulator lock up 3” or greater above run pressure: correct regulator and check gas pipe

sizing against piping chart in installation manual. Set regulator for maximum run pressure of 9”.3. Remove blower and inspect flameholder (burner) for hole.4. Check that the blower flanges and gas piping are sealed.

D. OCCASIONAL LOCKOUTS: Requires interruption of power to re-start or reset of safety limit.1. Air in system causes safety limit to open. Vent air form system and eliminate source of

air (9600 CB mostly).2. Condensing in primary heat exchanger or moisture in combustion chamber

a. defective element in diverting valveb. improper installation of intake terminalc. blocked condensate and condensate overflow system

3. Poor Combustion - check CO2 or O2.4. Intermittent igniter failure: defective igniter gasket allows igniter base to overheat.5. Occasional failure of blower: red “PURGE” light will be flashing.6. 9600 CB zone control short cycling or voltage problem: Operate thermostats in various sequences

to create suspect problem. Note: Three wire zone valves such as Taco or Watts must have isolatingrelay between end switch and HeatMaker 9600 CB.

800.900.9276 • Fax 800.559.1583 (Customer Service, Service Advisors)20 Industrial Way, Rochester, NH 03867 • 603.335.6300 • Fax 603.335.3355 (Applications Engineering)

1869 Sismet Road, Mississauga, Ontario, Canada L4W 1W8 • 905.238.0100 • Fax 905.366.0130www.Laars.com Litho in U.S.A. © Laars Heating Systems 0810 Document 2109

Service Manual for 9600 CB & HWG - LAARS Heating Systems

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Transcript of Service Manual for 9600 CB & HWG - LAARS Heating Systems