A.O. Smith 310 - DRAINING THE UNIT & CHECKING THE FILTER; GAS SUPPLY AND PRESSURE CHECKS

TroubleshootingGuide
21|Page
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DRAININGTHEUNIT: 
1) Closethemanualgasshutoffvalve.
2) Turnoffpowertotheunit,andthenturnonagain.
3) Wait30seconds,andthenturnoffpowertotheunit,yetagain.
4) Closethecoldwaterinletshutoffvalve.
5) Openallhotwatertapsinthe
house,oropenthepressure‐reliefvalvetoremovetheinitial
pressure.Whentheresidualwaterflowhasceased,closeallhotwatertaps.
6) Unscrewthedrainplugs(hotwateroutletdrainplugandcoldwaterinletfilter)todrainthe
remainingwateroutoftheunit.Haveabucket
orpantocatchthewaterfromtheunit’s
drainplugs.Waitafewminutestoensureallwaterhascompletelydrainedfromunit.
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CLEANINGTHE FILTER:
1) Draintheunit(procedureabove).
2) Checkthewaterfilterlocatedwithinthe
coldinlet.Withatinybrush,cleanthe
waterfilterofanydebriswhichmay
haveaccumulatedandreinsertthefilter
backintothecoldwaterinlet.
3) Securelyscrewthefilterbackintoplace.
Hand‐tightenonly.
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CHECKINGFORACROSSCONNECTION: 
1) Turnoffcoldwatersupply.
2) Turnonallhotwaterfixtures.
a. Thewatershouldeventuallycompletelydrain.
b. Ifwatercontinuestorun,thefixturesandplumbingsystemneedstobechecked.
c. Coldwatercrossconnectionsmayberelatedtoarecirculationpumpapplication,a
badcheck
valve,ormissingcheckvalveintheapplication.
CHECKFOR REVERSE C ONNECTION:
1) Closecoldwatersupplyattheinlet.
2) Openthepressure‐reliefvalve;itshouldbeinstalledonthehotsideoutletoftheunit.
3) Ifwatercontinuestorun throughthepressure‐reliefvalve,thesystemhasareverse
connection.
CHECKGA SSUPPLYPRESSURE:
1) Closethemanualgasinletshutoffvalve
onthegassupplyline.
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2) Openafaucet.Theunitshouldturnon
andthegasinthepipelineshouldpurge.
Leavethefaucetontokeeptheunit
runninguntilitshutsdownduetolackof
gas,andthenshutthefaucetoff.Ignore
anyerrorcodesthatmayoccurat
this
time.
3) Removethescrewforthepressureport
locatedonthegasinletshownontheright.
4) Connectamanometertothepressureport.
Figure17
Figure18