CORRECT USE OF

DISTRICT HEAT

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Correctuseofdistrictheat

©FinnishEnergyIndustries

ISBN978-952-5615-12-8

Illustration/LayoutJanneInkeroinen

PrintingLibrisOy,Helsinki

Reprinted2007

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CONTENTS

Districtheatisneat CorrectuseofdistrictheatsavesheatandmoneyHeatmeasurement Meterreadings Cooling Monitoryourenergyconsumption Heatindex

Heatingdegree-dayPressureanddifferentialpressureofthedistrictheatingnetworkStrainer Customerequipment Heatexchangers Balancingtheheatingnetwork Controldevicesfortheheatingnetwork Room-specific controlFloorheatingcontrolSettingofthecontrolcurve Impactofthecontrolcurveselectiononroomtemperature Checklist Servicewatercontroldevices Detectingaleakintheheatexchanger Pumps PressureoftheheatingnetworkandoperationofthemembraneexpansionvesselSafetydevices Temperatureandpressuremeters Instructionsforusersofdistrictheatingequipment Replacingthecustomer’sdistrictheatingequipment Iftheheatingdoesnotwork

DISTRICT HEAT IS NEAT

Districtheatingisanaturalformofheatingindensely-builtareas.Itkeepstheenvironmentcleanandimproveslivingcomfort.Districtheatingalsoconservesenergyandtheen-vironment to a significant extent. The greatest savings come fromcombinedproductionofdistrictheatandelectricity.Thissavesone-thirdoffuelcomparedwithseparateproductionofelectricityandheat.Italsocombatsclimatechange.DistrictheatinghasalsoreceivedrecognitionontheEUlevelforitsenergy efficiency.

District heating is reliable and flexible. The heat is pro-ducedintheeconomicallymostadvantageousmanner,

takingenvironmentalimpactsintoaccount.Districtheatingfuelsarenaturalgas,coal,peat,oil,wood

andotherrenewableenergysourcessuchasbiogas.Districtheatingalsoutilisestheleft-

overheatfromindustrialprocesses.

DistrictheatingisthemostpopularformofheatinginFinland.Itiscom-moninalmostalltownsandpopula-tioncentres.About2.5millionFinnsliveinhomesheatedbydistrictheat.Districtheatingaccountsforalmost50%ofthetotalheatingmarket.Almost95%ofapartmentbuildingsandabouthalfofterracedhouses,aswellasthebulkofpublicandcom-mercialbuildings,areconnectedtothedistrictheatingnetwork.Inthelargesttowns,themarketshareismorethan90%.

Districtheatisproducedincombinedheatandpower(CHP)plantsorinheatingplants.Customersreceiveheatthroughthehotwatercirculatinginthedistrictheatingnetwork.

Thetemperatureofdistrictheatingwatervariesbetween65and115ºC,dependingontheweather.Thetem-peratureisatitslowestinsummerwhenheatisonlyneededforhotserv-icewater.Thetemperatureofwaterreturningfromcustomerstothepro-ductionplantsrangesbetween25and50ºC.

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Ventilation36%

Roof6%An example of the distribution of energy consumption in a residential house. The consumption distribution is house-specific.

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CORRECT USE OF DISTRICT HEAT SAVES HEAT AND MONEY

Itispossibletosaveenergyinahousewithdistrictheatingwithoutgreatinvestments.Withcorrectandwell-adviseduseofheatingequipment,energyissavedwithouthavingtocompromiseovertherequirementsofhealthyliving.Whentheequipmentisingoodcondi-tion,theroomtemperatureremainscomfort-ableandstableandthereisalwaysenoughhotservicewaterofthecorrecttemperature.

Itisrecommendedthatroomtemperaturesareadjustedaccordingtotheuseoftherooms.

Recommended indoor temperatures:

• home and office 20-22ºC•shops,workshopsandindustrial premises18ºC•heatedstorerooms12ºC•garages5ºC

Energy saving tips

•Makesurethatroomtemperaturesareatanappropriatelevel• Air the rooms quickly and efficiently•Makesurethatwindowsanddoorsare sufficiently tight•Avoidunnecessaryuseofwater•Monitoryourenergyandwaterconsumption

HEAT MEASUREMENT

Thethermalenergyconsumedinthebuildingismeasured.Thecomponentsoftheheatmeterarea flow sensor, temperature sensors and a calcula-tor. The flow sensor measures the volume of circul- atingdistrictheatingwater.Thetemperaturesen-sorsconstantlymeasurethetemperaturesofwatergoingintoandcomingoutofthebuilding.Thecalculatorcalculatesthethermalenergyconsumed.Consumptionisshowninmegawatt-hours(MWh).Theheatsupplierownsthemeteringequipment.

Forexample,thefollowingdatacanbereadfromtheheatmeter:

•thermalenergy•volumeofcirculatingdistrictheatingwater•momentarycoolingofthedistrictheatingwater•momentarytemperaturesofthesupplyandreturnwaterofthedistrictheatingwater• momentary heat effect and water flow

Windowsanddoors15%

Walls17%

Base floor 4% Servicewater22%

A drop of just one degree in room temperature means a saving of about five per cent in annual energy consumption.

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Thecalculatorcalculatesconsumptionaccordingtothefollowingformula:

Q = V ∙ ∆t ∙ 1.163

Heat consumption (kWh) = volume of circu-lating district heating water (m3) x tempera-ture difference (cooling, ºC) x specific factor of water 1.163.

1 MWh = 1,000 kWh (kilowatt-hours)

METER READINGS

Thecustomersendsmeterreadingstotheheatsupplieraccordingtoinstructions,ortheheatingcompanyreadsthemeterremotely.

COOLING

Thetemperaturedifferencebetweenthedistrictheatingwatergoingintothebuildingandthewa-tercomingoutofthebuildingiscalledthecoolingofdistrictheatingwater.Thehigherthecoolingis,thebetterthedistrictheatingequipmentofthebuildingisworking.

Thereasonsshouldbedeterminedifcoolingisunder25°Corifitdiffersconsiderablyfromvaluesrecordedearlier.Therealisedcoolingofdistrictheatingwaterisoftenalreadycalculatedonthebillorconsumptionreportsentbytheheatsupplier.

Monitor cooling on a regular basis!

MONITOR YOUR ENERGY CONSUMPTION

Districtheatingcompaniesprovidetheirclientswithfollow-upreportsonenergyconsumptionatleastonceayear.Inmanylocations,customerscanmonitortheirconsumptiondirectlyontheheatsupplier’swebsite.Theeffectoftheweatheristakenintoconsiderationwiththeheatingde-gree-dayinthecomparisonofannualconsump-tion.Thereportsusuallyincludeadjustmentfortheweather.Ifcurrentconsumptiondifferscon-siderably from the figures for previous years, it is advisabletoinspecttheadjustmentsandcondi-tionoftheequipment.

Yourheatsupplierwillprovideadditionalinforma-tiononyourenergyconsumptionandmeasure-ment.

Inform your energy or district heating com-pany if you have carried out any saving measures in your house, if you stop heating for a longer period or if there are any other changes having an effect on energy consumption.

HEAT INDEX

Theheatindexistheheatconsumptionadjusted(normalised)withtheheatingdegree-daytothenormalyearperonebuildingcubicmetreayear(kWh/m3/year).Theheatingdegree-dayhasbeendevelopedforheatcalculationsofbuildings.Withtheheatingdegree-day,itispossibletocompareindividualheatconsumptionindifferentmonthsoryearsandtocompareitwiththeconsumptionofother,correspondingbuildings.Localheatingdegree-daysarecalculatedbytheFinnishMeteorologicalInstitute.

An example of calculating the heat index:

HousingCompanyHomeSweetHome(apartmentbuilding)

• totalvolume7,000m3• normalisedenergyconsumption310MWh=310,000kWh

Heatindex:310,000kWh = 44.4 kWh/ m3

7,000m3

Normalisingisonlydirectedattheenergyusedforspaceheating;theheatingofserv-icewaterdoesnotdependontheoutdoortemperature.Energyanddistrictheatingcompaniesprovideinforma-tionaboutthecalculationoftemperatureadjustments.Theheatsupplierusuallycalculatesthenormalisedconsumptionofabuilding

andentersitontheheatingbillorconsumptionreport.

Furtherinformation:www.motiva.fi/kulutuksen-normitus(onlyinFinnish)

Inform the heat supplier immediately if you suspect that the strainer is blocked.

PRESSURE AND DIFFERENTIAL PRESSURE OF THE DISTRICT HEATING NETWORK

Thepumpsinthedistrictheatingproductionplantordistrictheatingnetworkcirculatethedistrictheatingwaterinthecustomer’sdistrictheatingequipment.Thepressureandthedifferentialpressure in the network fluctuate constantly. They aregenerallyhigherinwinterthaninsummer.

STRAINER

The strainer filters the largest impurities of the water in the district heating network. The first sign ofablockageisthelowtemperatureofhotservicewater.Ifthestrainerisbadlyblocked,theheatsupplymayalsobeaffected.Whenthestrainerisblocked,thepressuremetersontheprimarysideofdistrictheatingshowalmostthesamereadings.

District heating supply pipe

District heating return pipe

Heat supplier’s main shut-off valves

Customer’s main shut-off valves

Flow sensor

Strainer

Calculator

Temperature sensors

District heating equipment owned by the heat supplier

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HEATING DEGREE-DAY

Heatingdegree-dayisobtainedbyaddingupthedifferencebetweenthedailyindoorandoutdoortemperaturesforeachmonth.Themostcommon-lyusedheatingdegree-dayisS17,whichiscal-culatedonthebasisofthedifferencebetweentheassumed 24-hour mean value of +17°C between theindoorandoutdoortemperature.Themonthlyheatingdegree-dayisthesumofthedailyheatingdegree-days,andcorrespondinglytheheatingdegree-dayfortheyearisthesumofmonthlyheatingdegree-days.Dayswithanaveragetemperature of more than +10°C in the spring and more than +12°C in the autumn are not takenintoaccountinthecalculationoftheheatingdegree-day.Thus,itisassumedthattheheatingofbuildingsisstoppedandstarteddailywhentheoutdoortemperatureexceedsorfallsbelowtheabove-mentionedlimits.

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HEAT EXCHANGERS

District heating water heats the water that flows throughtheheatexchangers,whichisthenusedforthebuilding’sspaceheatingsystemandforhotservicewater.Theheatexchangerskeepthewaterinthedistrictheatingnetworkandthebuilding’sheatingandhotservicewaterseparatefromeachother.Heatexchangersaredurableandtheydonotneedmuchserviceormaintenance.

Regulator

Summer shut-off

Control valve for heating

Control valve for service water

Customer’s main shut-off valves

Safety valve

Expansion vessel

Heat exchanger for heating

Heat exchanger for service water

Service water

Cold water

Pump

Heating network

Filling valve

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CUSTOMER’S DISTRICT HEATING EQUIPMENT

Theequipmentinthesubstationincludestheheatexchangersforheatingandservicewaterand,possibly,aheatexchangerforairconditioning,controldevices,pumps,expansionandsafetyequipment,thermometersandmanometers,andshut-offvalves.Customersacquiretheirdistrictheatingequipmentandtherelatedinstallationworkfromheatingcontractorsor,ascomprehen-sivedeliveries,fromenergyordistrictheatingsuppliers.Thedistrictheatingequipmentispres-sureequipment.

Thesubstationislocatedintheheatdistributionroom. A sufficient amount of space should be re-servedforthesubstationandthesupplier’sequip-mentformaintenancepurposes.Theconnectiondiagramfortheequipmentisdisplayedonthewalloftheheatdistributionroom.

The heat distribution room is used for district heating equipment only. Its door is to be kept locked. The heat supplier shall have free access to the heat distribution room.

Districtheatisverysafe.However,hotdistrictheatingwaterandhotsurfacesmustbehandledwithcare.Districtheatingwaterisnotsuitablefordrinking.

Balancingofthespaceheatingnetworkisprofessionalwork,anditpaystoletanexpertcompanytotakecareofitsplanningandimplementation.Theheatingnetworkisbalancedbyregulatingtheprecontrolvaluesoftheradiatorvalvesand,ifnecessary,possiblebalancingvalves.Thedimensioningoftheheatingpumpisalsoinspectedinconnectionwiththebalancing.

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BALANCING THE HEATING NETWORK

Thebalanceoftheheatingnetworkisthefoun-dationofwell-functioningheating.Thebasicadjustmentoftheheatingnetworkensuresthatthetemperatureineachroomremainsatthedeterminedlevel.Whenhavingcorrecttempera-tures,theneedforairingisreducedandenergyuse becomes more efficient. An unbalanced space heatingnetworkwastesthermalenergybecauseexcessivelyhotwaterwillhavetobefedintotheradiatorsofthewholebuilding.

The radiators are functioning correctly when their upper parts are warm and the lower parts at almost room temperature. The radiators are warm only when the room temperature falls below the set value.

SETTING OF THE CONTROL CURVE

Thecontroldevicesofvariousmanufacturersaredifferentfromoneanother.Computer-basedregulationandcontrolsystems(DDCcontrol)are house-specific and very different. The fol-lowinginstructionsareofprincipleonly:

Thesettingofthecontrolcurveusuallytakesplaceprogrammatically,inwhichcasetheuserdeterminesthesetvaluesofthesupplywatertemperatureforvariousoutdoortemperatures.Thesupplierofthecontrolsystemprovidesde-tailedinstructionsonthesettingofthecontrolcurve.

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CONTROL DEVICES FOR THE HEATING NETWORK

Thecontroldevicesinthesubstationregulatethewater temperature in the radiator or floor heating networkaccordingtotheoutdoortemperature.

Whentheregulationsystemistunedandfunctioningcorrectly,thewatertemperatureenteringtheheatingnetworkautomaticallyremainsatthecorrectlevelthroughouttheyear.

Thecontrolcurvechosenatthecontrolcentreisspecific for each building. Unnecessary increase of thecontrolcurveshouldbeavoided.

Thefunctionsandequipmentofthecontrolcentreinclude:

•settingofthecontrolcurvefordetermining thetemperatureofthewaterenteringthe radiators or floor heating •parallelshiftofthecontrolcurve•possibilitytoreduceindoortemperature•programselectorswitch(forexample, clockcontrol,dayornightprogram,manualoperation,mechanicalcontrols)• timer for 24-hour or weekly programs•indicatorforvalvemovementdirection•alarmfunctions

ROOM-SPECIFIC CONTROL

Thethermostaticradiatorvalvepreventsexcessive heating of the room. Room-specific thermostaticvalvestakeintoaccounttheextraheatfromthesun,electricappliances,lightingandpeople.

FLOOR HEATING CONTROL

It is possible to have partial or full underfloor heating in a building. Underfloor heating always requiresaseparatecontrolsystem.Excessivelyhot water must not enter the underfloor heat-ingnetwork.Supplywatertemperaturethatistoo high may damage pipes, floor structures and coatings. A high floor surface temperature is also unhealthyandwastesenergy.Thewatertem-perature leaving the floor heating circuit must not exceed 45ºC under any circumstances. If thetemperaturerisesabovethepermittedlevel,thepumpstopsandwillonlystartagainoncethetemperaturehasfallen.

Read the instructions for the control carefully.

Shifting of thecontrol curveup or downwards

Setting of thecontrol curve

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Impact of the control curve selection on room temperature

Thesetcontrolcurveistoosteep.Theroomtemperatureistoohighincoldweather.Remedy: the control curve is adjusted to a more gently sloping position

Thesetcontrolcurveistoogentle.Theroomtemperatureistoolowinverycoldweather.Remedy: the control curve is adjusted to a steeper position

Theslopeofthecontrolcurvehasbeenselectedcorrectly,buttheroomsaretoohotwithalloutdoortemperatures.Remedy: the curve is parallel-shifted downwards. (Atemperaturechangeofapproximatelythreedegreesinthesupplywatertemperaturechangestheroomtemperaturebyaboutonedegree.)

The correct control curve has been found when the room temperature remains stable and suitable under all conditions.

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CHECK LIST

•Read the operating instructions of the control equipment carefully and follow the instructions.

• A correctly set control curve guarantees the desired room temperature in all normal weather conditions.

•The control curve is building-specific, and you may have to seek for the correct curve. The control curve selected at the installation stage is directive only.

•Write down the changes made to the set values of the control devices in different weather conditions.

•When adjusting the control values, it will take a few days before the room temperatures are normalised.

•If the building’s control centre includes extra functions, e.g optimisation, learn how to use them.

• If in doubt, ask the supplier of the control devices or the heat supplier for advice.

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TIMER

Thetimerreducestheroomtemperatureforthedesiredperiodoftime.

SERVICE WATER CONTROL DEVICES

Thetemperatureofservicewaterisadjustedbymeansofacontrolvalveonthedistrictheatingside.Thetemperatureoftheservicewateris55°C.Thetemperatureoftheservicewatermustnotbereducedforthenightwiththetimer.

Incorrectlydimensionedorpoorlyfunctioningcontroldevicesforservicewatermaycause,forexample, fluctuation in the service water tem-perature.Thereasonforthefaultmustalwaysbeestablishedandrepaired.

DETECTING A LEAK IN THE HEAT EXCHANGER

Theheatexchangerforheatingmayhaveanin-ternalleakifthesafetyvalveintheheatingnet-work is leaking. A filling valve that has been left openmayalsobethereasonfortheleak.

It is more difficult to detect an internal leak in the heatexchangerforservicewater.Theconditionofheatexchangersforservicewaterthatareover10yearsofageshouldbecheckedaboutonceayear.Aleakintheheatexchangerforservicewa-tercanbedetectedasanincreaseinwaterandenergy consumption and fluctuations in the servicewatertemperature.

Manyenergyanddistrictheatingcompaniesaddacolouringagentinthedistrictheatingwater,whichhelpstodetectaleak.Thereisaleakintheheatexchangerifthehotservicewaterhasagreenishcolour.

Contact your heat supplier immediately if you suspect a leak in the heat exchanger.

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Fillingvalve

PUMPS

Theheatingpumpcirculatesthewaterinthebuilding’sspaceheatingnetwork.

Thecirculatingpumpforservicewaterkeepsthetemperatureoftheentireservicewaternetworkatthecorrectandeventemperature,whichpre-ventsunnecessaryhotwaterconsumption.Theservicewaterpumpiskeptrunningatalltimes.

Read carefully the operating and main-tenance instructions for the pumps.

PRESSURE OF THE HEATING NETWORK AND OPERATION OF THE MEMBRANE EXPANSION VESSEL

Thepressureinthespaceheatingnetworkin-creaseswhenthetemperaturerises.Duringthecoldperiod,thepressureishigherthaninspringorautumn.

Theexpansionequipmentkeepsthewaterinallradiatorsandthepressureeven.Themostcom-monmodelofexpansionvesselisthemembraneexpansionvessellocatedintheheatdistributionroom.Thewaterexpandsasitbecomeshotter,and water flows into the membrane expansionvessel.Whencooling,thevolumeofwaterdiminishes and water flows out of the membrane expansionvesselintothespaceheatingnetwork.

Thesizeandinitialpressureofthepressureves-selisdimensionedsothatthereisnoneedtoaddwatertotheclosedspaceheatingnetworkequippedwithamembraneexpansionvessel.Thepressure vessel is faulty or the filling valve is leak-ingifthepressureofthespaceheatingnetworkrisesconstantlyandwaterisleakingthroughthesafetyvalve.

Itisnotnecessarytoaddwatertothespaceheatingnetworkiftheradiatorsarebledandtherearenoleaksinthenetwork.Thereasonforanyconstantneedtoaddwatermustalwaysbeestab-lished.

Waterisaddedtothespaceheatingnetworkthrough the filling valves.

SAFETY DEVICES

Thesafetyvalveofthespaceheatingnetworkprotectstheradiatorsandtheexpansionvesseleven if the filling valve is left open or there is an internalleakintheheatexchanger,inwhichcasethepressureofthedistrictheatingwaterwillhaveaneffectonthespaceheatingnetwork.Insuchacase,thesafetyvalveopensandleakswater.

Thesafetyvalveintheservicewaternetworkpreventsapressureincreaseofover1.0MPa(10bar).

TEMPERATURE AND PRESSURE METERS

Thecustomer’sdistrictheatingequipmenthaspressureandtemperaturemetersforcheckingthattheequipmentisfunctioningcorrectly.Thepressuremetersindicatethepressuresoftheheatingandwatersystemnetwork.Thepressuremetersfordistrictheatingindicatethepressureandthedifferenceinavailablepressure.

Thethermometersindicatetheservicewatertemperatureandthesupplyandreturnwatertemperatureofthespaceheatingnetwork.Whenthespaceheatingnetworkisinbalance,there-turntemperatureisclearlylowerthanthesupplytemperature.Therearealsothermometersinthedistrictheatingsupplyandreturnpipe.Thediffe-renceintheirreadingsisthemomentarycoolingtemperatureinthedistrictheatingwater.

Thereisathermometerwithanalarmintheservicewater.Itraisesthealarmifthetempera-turerisesabove65ºC.Checkthecontrolvalveand find out the reason for the alarm.

Remember

• to keep the heat distribution room tidy

• to monitor the functioning of the equip-ment in accordance with the operating instructions

• to learn to use the control devices, pumps, expansion and safety equipment and other technical devices in the

correct manner

• to keep the shut-off valves of the pres-sure meters closed. (They are opened when the pressure is checked)

• to supply the readings of the heat meter in accordance with the heat

supplier’s instructions, when necessary

• to monitor your heat consumption and cooling

• to ensure that any faults are repaired or to report them further

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Thetemperaturelevelsfortheheatingnetworkare specific for each building. In conventional ra-diatorheating,thesupplywatertemperatureisamaximumof70ºC.Inoldbuildings,thewatertemperatureneedinthecoldestperiodsmaybeupto80ºC.

In underfloor heating systems, the supply water temperaturemustnotrisetoohigh.Plasticpipesare normally used in floor heating. The tempera-ture of water flowing in the pipes must be below 45ºC.

Temperature below –15ºC

•Cancelthenight-timetemperaturedroporensurethattheautomaticfunctionstakecareofitautomatically•Ensurethatthereisnodangeroffreezingintheradiatorsoftheventilationdevices

Summer

•Ensurethatthecontrolvalveisclosedandre-mainsclosedor,ifnecessary,closethesum-mershut-off•Iftheheatingpumpsarestopped,startthemuponaweeklybasis

Spring and autumn

•Ensurecorrectcontrolvalues•Selectsuitablenighttemperatureswiththe timerandparallelshift•Checktheclocksinthecontroldevicewhenswitchingbetweenwintertimeandsummertime•Checkthepressureofthespaceheatingnet-workwhentheheatingperiodstarts•Checkthetemperatureofthehotservicewater

INSTRUCTIONS FOR USERS OFDISTRICT HEATING EQUIPMENT

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REPLACING THE CUSTOMER’S DISTRICT HEATING EQUIPMENT

Theconditionandfunctioningofcustomerequip-mentmustbeinspectedonaregularbasis.Afullsurveyisrecommendedfortheequipmentafter15yearsofserviceatthelatest.Conditioninspec-tionsandsurveysarecarriedoutbytheinspec-torsofenergyanddistrictheatingcompanies,heatcontractors,equipmentmanufacturersandheatingandventilationdesigners.Thefunctioningoftheequipmentandanypossiblereplacementneedsareestablishedinthesurveyofthedistrictheatingequipment.

Theextentofreplacementisalwaysassessedseparatelyineachcase.Newequipmentisdimen-sionedtoequaltherealheatingneedofthebuild-ing,whichsavesacquisitioncosts.Thecontractedwater flow/heat capacity is also checked at the sametime.

Always contact your heat supplier before replacing any equipment.

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ADD MORE WATER TO THENETWORK AND CHECKPOSSIBLE FAULTS

STOP THE VENTILATIONEQUIPMENT, IF NECESSARY

SWITCH THE HEATING TOMANUAL OPERATIONIF THE FAULT REMAINS

ASK THE HEAT SUPPLIERTO CLEAN IT

STOP THE VENTILATIONEQUIPMENT

THERE MAY BE A LEAKIN THE SYSTEM OR A FAULTIN THE PRESSURE VESSEL

IS THE NETWORK PRESSURECORRECT (A SUFFICIENTAMOUNT OF WATER)?

THERE MAY BE A FAULTIN THE SWITCHES OR FUSES

ARE THE PUMPS WORKING?ARE THE SHUT-OFF VALVESIN THE CORRECT POSITION?

THE SETTINGS OF THE CONTROL DEVICES MAY BE INCORRECT

ARE THE CONTROLDEVICES WORKING?

BLOCKED STRAINERPRESSURE DIFFERENCEIN THE CIRCULATION OFDISTRICT HEATING WATER

DISRUPTION IN THE HEAT SUPPLIER’S HEATDELIVERS

MALFUNCTION ?

IF NECESSARY, CONTACT AN EXPERT

MEASURES

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below65°C

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YES

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FAULT IN THE HEAT SUPPLIER’S EQUIPMENT

CUSTOMERS OWN EQUIPMENT

IF THE HEATING DOES NOT WORK

SUPPLY WATER TEMPERATUREOF THE CIRCULAITING DISTRICT HEATING WATER