User Guide

78
LH(”Reset”)
FIGURE 14.3: RESET BUTTON
Condensate Trap–Thecondensatetrapallowscondensatetoleavetheboilerwhilecontaininguegasses.Intheeventthat
this trap becomes blocked, condensate will start to back up in the trap. To prevent a rising condensate level from backing up
intotheheatexchanger,bothagroundwireandtheamerodwirearebondedtothistrapinsuchawaythatanabnormallyhigh
condensatelevelwillconductamecurrentdirectlytoground(Figure10.5).Theboilercontrolwillinterpretthisasalossof
ameandenteraHold.SeeFigures7.25or13.3fortraplocation.
Combustion Fan–Thecombustionfanpushesair-fuelmixtureintotheburnerandthespeedofthisblowerdeterminesthering
rate. There are two electrical connections at this fan:
 • 120VPlug–Supplies120VACPowertotheFan
 • SpeedControlPlug - Delivers a PWM (speed control) signal from the boiler control to the fan. This plug also includes
` tachometer connections so that the boiler control can monitor the actual fan speed.
In the event that there is 120volts at the boiler, but no signal at the speed control plug, this fan will run at its maximum speed.
Speciccausesofthisinclude:
 • Disconnectedspeedcontrolplug
 • LooseJ2Plug
 • LooseL2orL3Plug
 • Defective24VTransformer
Gas Valve–Thegasvalveusedonthisboilerhaseitheroneortwo24VDCcoils(thegasvalveusedonallboilermodelsis
redundant).Thegasvalveoutputfromtheboilercontrolis24VAC.Arectiermoduleisinstalledbetweenthegasvalveandthe
wiringharnessonthe80,100and120models(Figure11.4a).Therectierisbuiltintothegasvalveplugitselfonthe150and
180.