Specifications

TroubleshootingGuide
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5|Page
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3.NORMALOPERATION
Becomingfamiliarwithhowatanklesswaterheaternormally
operatesmayhelptotroubleshootit.Assumingitisproperly
installed with appropriate gas, water, and electric
connections,thefollowingishowitshouldoperate:
1) ACTIVATION
a. Ahotwatertapisopenedenoughthattheflow
sensordetectsaflowratethroughtheheatergreater
thantheactivationpointof0.5gpm.
b. Thefanactivatesafterflowisdetected.
c. Thecomputerchecksforanyproblemswiththeunit
beforestartup.
d. Igniteractivates.You
canhearthebuzzingofthe
sparkigniter.
e. Maingasvalve,proportionalvalve,andsolenoidgas
valveswillopen.Youwillhearadeep“clunkclunk”
noise.
f. Onceaflameisdetected,theredLEDlocatedon
thecomputerboardwillactivate.
g. Inamulti‐he ater setup, 
thecontrollerwill
activatethenextheaterin2‐4gpmincrements,
dependingonthesettemperature.
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2) OPERATION
a. Theproportionalgasvalvewillmodulatebasedontheamountofhotwaterdemandedandthe
temperatureriseneeded.Thefanspeedwillmodulateaswelltocreateanefficientburn.
b. Youwillnoticethatonlypartialsectionsoftheburnerwillbelit.Thisisnormaloperation;there
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arethreesectionsontheburnerassembly,andthecomputercontrolstheamountof sections
neededbasedontheflowrateandtemperatureriserequired.
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3) SHUTDOWN
a. Theheaterwillshutdownwhenthewaterflowratedropsbelowthedeactivationpointof
0.4gpm.
b. Theheaterwillclosethemaingasvalveandsolenoidgasvalves,extinguishingtheflame.
c. WhentheflamedisappearstheredLEDwillturnoff.
d. Thefanwillincrease
inspeedtopurgetheventingofanyremainingexhaustgases.Thelength
ofpost‐purgecanlastupto1½minutes.
e. Theheatergoesintostandbywaitingfortheprocesstobeginagain.
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*Thepurposeofthisdiagramistoillustratetanklesswater
heaterdesignconcepts,andmaynotbeaccuratetothe
unit’sphysicaldescription.
Figure2