A.O. Smith BL-80 - Anode Rod Inspection and Testing; Anode Rod Function and Maintenance; Property Damage Prevention; Temperature-Pressure Relief Valve

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WhencheckingtheTemperature-PressureReliefValveoperation,
makesurethat(1)nooneisinfrontoforaroundtheoutletofthe
Temperature-PressureReliefValvedischargeline,and(2)thatthe
waterdischargewillnotcauseanypropertydamage,asthewater
maybeextremelyhot.Usecarewhenoperatingvalveasthevalve
maybehot.
Tocheckthereliefvalve,lifttheleverattheendofvalveseveraltimes,
seeFigure21.Thevalveshouldseatproperlyandoperatefreely.
Ifaftermanuallyoperatingthevalve,itfailstocompletelyresetand
continuestoreleasewater,immediatelyclosethecoldwaterinlet
tothewaterheateranddrainthewaterheater,seeDrainingAnd
Flushingonpage24.ReplacetheTemperature-PressureReliefValve
with a properly rated/sized new one, see Temperature-Pressure
ReliefValveonpage11forinstructionsonreplacement.
DISCHARGE PIPE
TEMPERATURE-PRESSURE
RELIEF VALVE
FIGURE 21.
IftheTemperature-PressureReliefValveonthewaterheaterweeps
ordischargesperiodically,thismaybeduetothermalexpansion.
NOTE:Excessivewaterpressureisthemostcommoncauseof
Temperature-Pressure Relief Valve leakage. Excessive water
systempressureismostoftencausedby“thermalexpansion”
ina“closedsystem.”SeeClosedWaterSystemsandThermal
Expansiononpage11.TheTemperature-PressureReliefValve
isnotintendedfortheconstantreliefofthermalexpansion.
Temperature-Pressure Relief Valve leakage due to pressure
build up in a closed system that does not have a thermal
expansion tank installed is not covered under the limited
warranty. Thermal expansion tanks must be installed on all
closedwatersystems.
DO NOT PLUG THE TEMPERATURE-PRESSURE RELIEF
VALVE OPENING. THIS CAN CAUSE PROPERTY DAMAGE,
SERIOUS INJURY OR DEATH.
Explosion Hazard
Temperature-Pressure Relief Valve
must comply with ANSI Z21.22-
CSA 4.4 and ASME code.
Properly sized temperature-
pressure relief valve must be
installed in opening provided.
Can result in overheating and
excessive tank pressure.
Can cause serious injury or death.
RECOMMENDED PROCEDURE FOR PERIODIC
REMOVAL OF LIME DEPOSITS FROM TANK TYPE
COMMERCIAL WATER HEATERS
Theamountofcalciumcarbonate(lime)releasedfromwateris
indirectproportiontowatertemperatureandusage,seechart.
Thehigherthewatertemperatureorwaterusage,themorelime
depositsaredroppedoutofthewater.Thisisthelimescalewhich
formsinpipes,heatersandoncookingutensils.
INSTALLEDINSUITABLEAREA:Toinsuresufficientventilation
and combustion air supply, proper clearances from the water
heatermustbemaintained.SeeFactstoConsiderAboutThe
Location section. Combustible materials such as clothing,
cleaningmaterials,orflammableliquids,etc.mustnotbeplaced
againstoradjacenttothewaterheaterwhichcancauseafire.
ANODE ROD INSPECTION
Property Damage Hazard
•
Avoid water heater damage.
•
Inspection and replacement of anode rod required.
CAUTION
Theanoderodisusedtoprotectthetankfromcorrosion.Mosthot
watertanksareequippedwithananoderod.Thesubmergedrod
sacricesitselftoprotectthetank. Instead of corroding the tank,
waterionsattackandeatawaytheanoderod.Thisdoesnotaffect
water’stasteorcolor.Therodmustbemaintainedtokeepthetank
inoperatingcondition.
Anodedeteriorationdependsonwaterconductivity,notnecessarily
watercondition.Acorrodedorpittedanoderodindicateshighwater
conductivityandshouldbecheckedand/orreplacedmoreoftenthan
ananoderodthatappearstobeintact.Replacementofadepleted
anoderodcanextendthelifeofyourwaterheater.Inspectionshould
beconductedbyaqualiedservicetechnician,andataminimum
shouldbecheckedannuallyafterthewarrantyperiod.
Articially softened water is exceedingly corrosive because the
processsubstitutessodiumionsformagnesiumandcalciumions.
The use of a water softener may decrease the life of the water
heater tank.
Theanoderodshouldbeinspectedafteramaximumofthreeyears
andannuallythereafteruntiltheconditionoftheanoderoddictates
itsreplacement.
NOTE: Articially softened water requires the anode rod to be
inspectedannually.
Thefollowingaretypical(butnotall)signsofadepletedanoderod:
• Themajorityoftherodsdiameterislessthan3/8”.
• Signicantsectionsofthesupportwire(approx.1/3ormoreof
theanoderod’slength)arevisible.
TEMPERATURE-PRESSURE RELIEF VALVE TEST
Burn hazard.
Hot water discharge.
Keep clear of Temperature-
Pressure Relief Valve
discharge outlet.
ItisrecommendedthattheTemperature-PressureReliefValve
should be checked to ensure that it is in operating condition
every6months.