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HVAC System Service and Design

Dan SpurgeonEngineering ManagerCab Climate Systems February 15, 2017

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Agenda

• CAT Machine Service Updates • Quality Improvements

• Product Enhancements

• Cabin Air Quality• New Regulations & Hardware Offering

• Troubleshooting Frequent Clutch Cycling

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Agenda

• CAT Machine Service Updates • Quality Improvements

• Product Enhancements

• Cabin Air Quality• New Regulations & Hardware Offering

• Troubleshooting Frequent Clutch Cycling

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Service Update – Super Heavy Duty Clutches

IssueDesire for increased service interval for refrigerant compressors

ResolutionOptional service replacement compressors with super heavy-duty clutch now available

Features• Improved friction material on surfaces of pulley

and armature• Leaf springs replaced with rubber • 3 – 4X improvement in clutch service life• Available on multiple machine models

Original PartSuper

Heavy‐duty Option

Pulley Size Port Style

163‐0872394‐9671

464‐9988 133 mm O‐ring

183‐5106 501‐1179 152 mm O‐ring

320‐1291 472‐0559 133 mm Dual Seal

324‐9711 507‐3868 130 mm Dual Seal

NOTE:   All models are 24 volt, Pad Mount, and have PV8 pulley 

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IssueThe existing air conditioner pressure switch may fail due to excessive vibration on certain 735C, 740C, and 745C Articulated Trucks.

ResolutionRelocate pressure switch from refrigerant compressor to high pressure discharge line.

Service LetterTEBE5358-01

Quality Update – Relocate Pressure Switch

Affected Models• 735C (S/N: LFJ1-UP; TFJ1-UP)• 740C EJECTOR (S/N: LFN1-UP; TFN1-UP)• 745C (S/N: JE81-UP; JE91-UP; LFK1-UP; TFK1-UP)

Parts Required

Qty Part Number  Description1  510‐3475  Line Assembly2  327‐0282  Integral Seal1  355‐3148  Pressure Switch1  9X‐7378  O‐Ring Seal1  125‐1149  Harness As

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Quality Update – Water Valves

IssueCooling systems on certain machines have increased coolant pressures. Existing water valves have lower life when exposed to these higher coolant pressures. ResolutionThe new 465-7630 Water Valve Gp is replacing the former 361-1289 Water Valve Gp

Affected ModelsLandfill Compactor• 826H (S/N: AWF1-UP)• 836H (S/N: BXD1-UP)Soil Compactor• 825H (S/N: AZW1-UP)Wheel Dozer• 824H (S/N: ASX1-UP)• 834H (S/N: BTX1-UP)Wheel Loader• 988H (S/N: A7A1-UP; BXY1-UP)

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(A) 25.4 mm (1.00 inch)

1. Remove heater hose and clean the surface of the formed tube2. Reinstall the heater hose to tube with dimensions (A) from

bead to hose end.3. Inspect hose clamp for damage and replace as needed.4. Position the hose clamp to the correct distance from the hose

bead. The distance from the end of the hose clamp closest to the hose bead should be dimension (B).

5. Preferred hose clamps: 9X-2488 or 159-1503. Torque the clamp to 7.5 ± 1 N·m (66.38 ± 8.85 lb in). (B) 5 mm (0.196 inch)

Note: Use of a manual torque wrench is preferred to attain 7.5 ± 1 N∙m (66.38 ± 8.85 lb in).  Do not use a pneumatic torque tool. 

Quality Update – Clamping Coolant Lines

IssueCooling systems on certain machines have increased coolant pressures. Proper clamp installation is more critical than ever to prevent leaks!ResolutionFollow process shown below.

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IssueSeal leak inside conditioner group by applying RTV sealant to the long edge seam inside the air duct. Condensate will be noticed on cab floor or inside air duct if leak is present.

Quality Update – D6T Climate System (part 1)

Resolution1. Remove AC/Heater box motor housing cover.2. Eight screws secure the cover to the AC/Heater box. One screw on

each side and three each on the top and bottom. 3. The cover slides out best with bottom edge tucked into the box and

tilted to clear the platform wall on the machine right-hand side.4. Apply a generous bead of RTV sealant to the seam of the

AC/Heater box between the drip passage and the air passage. 5. Gap is biggest on the top side of the seam nearest both corners.

Affected Models• D6T LGP (S/N: HTZ1-644 )• D6T LGP PAT (S/N: RAD1-992)• D6T XL (S/N: KMR1-590)• D6T XW (S/N: TMY1-361)• D6T XW PAT (S/N: STE1-117)

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Quality Update – D6T Climate System (part 2)

Affected Models• D6T LGP (S/N: HTZ1-644 )• D6T LGP PAT (S/N: RAD1-992)• D6T XL (S/N: KMR1-590)• D6T XW (S/N: TMY1-361)• D6T XW PAT (S/N: STE1-117)

Resolution1. Recover refrigerant from A/C system. Record amount of oil removed

during refrigerant recovery.2. Pull vacuum on both high/low side of system for approximately 60

minutes.3. Follow directions in “Oil Amount” to determine if oil needs to be added

back into the A/C system. In most cases, oil should not need to added. 4. Charge A/C system with 1.8 kgs (4 lbs) R-134a through high pressure

line.5. Check A/C for proper operation

IssueRefrigerant and oil charge for the A/C system have been reduced. Change improves cooling performance.

Oil AmountRecovered oil < 116 ml = DO NOT ADD

Recovered oil > 116 ml (use formula below)

Recovered oil (ml) – 116 ml = add amount

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Agenda

• CAT Machine Service Updates • Quality Improvements

• Product Enhancements

• Cabin Air Quality• New Regulations & Hardware Offering

• Troubleshooting Frequent Clutch Cycling

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New OSHA Regulation – Air Quality

Impact to Construction Equipment

• Establishes exposure limit of 50 micrograms of respirable crystalline silica per cubic meter of air (50 μg/m3) as an 8‐hour time‐weighted average.  

NOTE:  1/2 the exposure limit of old rule

• Goes into effect June 23, 2017

Rationale – Reduce adverse health effects associated with exposure to respirablecrystalline silica; COPD for example.

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CAT Cabin Air Quality SystemUniversal Precleaner Kits

What Are YOU Breathing?

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CAT Cabin Air Quality SystemUniversal Precleaner Kits

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CAT Cabin Air Quality SystemFiltration Offerings

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CAT Cabin Air Quality SystemAccessories

836K Compactor

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Agenda

• CAT Machine Service Updates • Quality Improvements

• Product Enhancements

• Cabin Air Quality• New Regulations & Hardware Offering

• Troubleshooting Frequent Clutch Cycling

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Operator Complaint - poor cab cooling

Pressures fluctuating due to frequent compressor cycling – High side normal Low side low

Symptoms you might see during system diagnosis

Hmm

Troubleshooting Frequent Clutch Cycling

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Notice how rate of drop in cab temperature is slowed down once clutch cycling begins…

Clutch Cycling Impact on Cab Temperature

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Sensor/switch malfunction

Plugged filter(s)

Plugged evaporator fins

Restriction in the refrigerant circuit

Low refrigerant charge

Excessive Clutch Cycling – service related causes 

NOTE:  There are also possible design related issues, but these won’t be covered today!

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What might cause a dirt plugged evaporator?

How about an iced up evaporator?

Evaporator with Plugged Fins

Similar behavior as shown for plugged filter

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This might be a little too cold!

Restricted Orifice or TXV

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Impact of Low Refrigerant Charge

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Faster Cycle Rate Slower Cycle Rate

Additional Note – impact of compressor speed

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Excessive compressor cycling results in decreased evaporator capacity – hence the poor cooling complaint

Check basics first – filters, plugged coil, sensor problems, refrigerant charge

NOT ALL compressor cycling is bad – Expect to see increased frequency with mild ambient conditions and with increasing engine speed.

Summary

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Thank You!