Specifications

TroubleshootingGuide
26|Page
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6.MAINTENANCE
Safety is the most important part of this guide. These 
procedures must be done by a licensed competent
technician. AO Smith is not liable for the actions of the
technician if he/she fails to adhere to any or all safety
procedures, specifically in regards to electrical and gas
safety.

The910
/910ASME(T‐M50/T‐M50ASME)isa
combinationoftwotanklesswaterheatersinonecase.
Whentroubleshootingthisunit,itisimportanttoidentify
whichmajorassembly,leftorright,isthesidethatthe
problemislocated.Onceitisdeterminedwhichside
contains
theproblem,unlessspecificallystated,the
proceduresformaintenanceareexactlythesameforboth
theleftandrightheatexchangerassemblies.
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CLEANINGTHERODASSEMBLY
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a. TOOLS
‐Gatherthefollowingmaterialstogether:Sheetof100GritSandpaper,#2PhilipsScrew
Driver,Flashlight
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2) POWER
‐Disconnectpowertoyourunitbyeitherunpluggi ngitfromthewalloutlet,orbythecircuit
breaker,dependingonthesetup.PresstheGFI‘TEST(OFF)’button;iftheredlightdoesnotcome
on,powerissuccessfullydisconnected.
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3) FRONTCOVER
‐Removethefrontcover.
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4) RODASSEMBLY
–
a. Locatetheblack,yellow,andorangewireslocatedinthe
centeroftheunit.
b. RemovethethreePhillipsheadscrewsholdingthepanelin
place.
c. Pulltheassemblyout.Donotlosethecircularwindow.
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5) SENSORS
–Itisimportanttobeverygentlewiththesensorrodswhilecleaningthem,astheywill
easilybendoutofplace.Theiroriginalpositionrelativetotheburnerneedstobeunalteredto
functionproperly.
a. Cleantheflamesensorwith100gritsandpaper,thoroughlytoabright
finish.
b. Cleantheairfuelratiorodwith100gritsandpaper, thoroughlytoabrightfinish.
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6) REASSEMBLE
‐Reassembletheunitinreverseorder–sightglass,gasket,rods,andmetalcover.Key
pointstoremember:
a. Connectall3wiresonfrontofburner.
b. Inspectallofthegaskets.
c. Besurethecircularburnerwindowisstillinplace.
Figure25
Figure26
RodAssembly