Bard WG3S2-A Installation Instructions Manual

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Bard WG3S2-A Installation Instructions Manual Manual pdf 37 page image

Manual 2100-587BPage 37 of 5930. SEQUENCE OF OPERATION –HEATINGOn a call for heat from the thermostat, the induced draftblower is energized. Once sufficient draft isestablished, the pressure switch contacts close and theignition system is energized. The direct spark ignitorwill be energized allowing gas to flow. At the sametime the main valve is energized, a 30-second blowerdelay timer is activated.After this delay, the heating speed blower relayenergizes. The blower will begin operating and remainin operation until the set delay time after the call forheat has been satisfied. This timing sequenceguarantees blower on, blower off operation.This unit is equipped with a flame roll-out switch,which is wired in series with the control circuit. This isa manual reset switch and is used for the purpose ofpreventing possible fire hazard in the event of a systemmalfunction. If this switch has opened the controlcircuit, there could be a possible system malfunction.Some of the conditions that might cause a roll-out tooccur are blockage or sooting of primary heatexchanger, overfiring of furnace due to improper mainburner orifices or incorrect manifold pressure,insufficient combustion air, or installation deficiencieswith respect to return air duct design or sizing.Once the problem has been resolved, reset the switch bypressing down on the reset button on top of the switch.See Figure 16 for additional information.31. SEQUENCE OF OPERATION –COOLINGNON-ECONOMIZERStage 1 (Y1) cooling call activates Step 1 (partialcapacity, 66%) of compressor capacity.Stage 2 (Y2) cooling call activates Step 2 (full capacity,100%) of compressor capacity.WITH ECONOMIZERStage 1 (Y1) cooling call goes to economizer controlsfor decision:- If Enthalpy Control decides outdoor conditionsare suitable for free cooling, the economizer willoperate.• If Stage 2 cooling call is issued duringeconomizer operation, the economizer willclose and the compressor will go straight toStep 2 full capacity operation.- If Enthalpy Control decides outdoor conditionsare not suitable for free cooling, the economizerwill not operate (or close) and Step 1 of thecompressor will operate.• If Stage 2 cooling call is issued, thecompressor will shift to Step 2 full coolingcapacity operation.FIGURE 16SEQUENCE OF OPERATIONELECTRONIC BLOWER CONTROLNOITCA ESNOPSERMETSYS.taehrofsllactatsomrehT).dezigrenesilanimretW(•••••.dezigrenesirewolbrianoitsubmoC.dehsilbatsesiwolfriA.sekamhctiwsgnivorpriA.dezigrenesimetsysnoitingI.sthgilrenrubniamdnasnepoevlavsaGsinafgnitalucriceht,etelpmocsignimitnehW.snigebgnimityalednonaftaeH.deepstaehtadezigrene.taehrofllacsdnetatsomrehT •••.sesolcevlavsagdnadezigrene-edsimetsysnoitingI.gnimitegruptsopretfadezigrene-edsirewolbrianoitsubmoCsinafgnitalucriceht,etelpmocsignimitnehW.snigebgnimityaledffonaftaeH.dezigrene-ed.loocrofllacsnigebtatsomrehT).dezigrene-erslanimretYdnaG(••.dezigrenesirotcatnocgnilooC.gnimityalednonafloocretfadeepsloocnodezigrenesinafgnitalucriC.nafrofllacsnigebtatsomrehT).dezigrene-edsilanimretG(• dezigrene-edsinafgnitalucriC.snepo)tuolloremalf(timiL ••.sesolcevlavsagdnadezigrene-ederametsysnoitingidnatatsomrehTnarewolbrianoitsubmoC d .dezigreneeradeepstaehnafgnitalucrictuolloremalfro)teserotua(timiL.desolctiucric)teserlaunam(•••.gnimitegruptsoprofdezigrenesniamerrewolbrianoitsubmoC.gnimitffoyaleddetcelesehtrofdezigrenesniamernafnoitalucricehT.semusernoitarepolamroN