A.O. Smith GCV300 Service Handbook Download Page 32

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ALL TECHNICAL AND WARRANTY QUESTIONS SHOULD BE DIRECTED TO THE LOCAL DEALER FROM WHOM THE WATER HEATER WAS PURCHASED. IF

YOU ARE UNSUCCESSFUL, CONTACT A.O. SMITH WATER HEATERS RESIDENTIAL TECHNICAL ASSISTANCE AT 1-800-527-1953 OR WWW.HOTWATER.COM.

Summary of Contents for GCV300

Page 1: ...OR USE BY QUALIFIED SERVICE PROFESSIONALS ONLY LOW LEAD CONTENT Service Handbook Residential FVIR Gas Water Heaters MODELS GCV GCVH GVR GCVL GVRL GCVT SERIES 300 301 XCV XVR XCVL XGV XVRL XCVT SERIES 300 301 327726 001 May 2014 ...

Page 2: ...e Pilot Does Not Light 9 If the Pilot Lights but the Status Light Does Not Blink 9 Diagnostic Flash Codes 10 0 Flashes LED not lit 10 Status Light On solid 10 1 Flash 10 2 Flashes 10 4 Flashes 10 5 Flashes 10 7 Flashes 10 8 Flashes 10 System Checks 11 Draft Test 11 Connections Check 11 Gas Pressure Checks 11 Thermopile Check Open Circuit 12 Thermopile Check Closed Circuit 12 Common Issues 13 No Ho...

Page 3: ...d Flame Arrestor 18 Replacing the Manifold Burner Assembly 19 Testing the Igniter System 19 Removing and Replacing the Gas Control Valve Thermostat 20 Removing the Gas Control Valve Thermostat 20 Replacing the Gas Control Valve Thermostat 20 Draining and Flushing 20 Supplements 21 Evaluating Combustion and Ventilation Air Supply 21 Attic Installations 23 Overview 23 Pilot Outage 23 Elevated Air Te...

Page 4: ...s handbook for further assistance Additional information is also available on the web site listed on the back cover of this handbook This handbook is intended for use by licensed plumbing professionals and reference should be made to the Installation Instructions and Use Care Guide accompanying the product This handbook contains supplemental information to the Installation Instructions and Use Car...

Page 5: ...ustibles Keep ignition sources away from faucets after extended period of non use Read instruction manual before installing using or servicing water heater Fire or Explosion Harzard Hydrogen gas can be produced in a hot water system after a period of non use generally two or more weeks Hydrogen gas is extremely flammable and can ignite To return hot water system to service open a hot water faucet ...

Page 6: ... 2 inches wider than the diameter of the water heater Sediment Trap 3 Minimum Gas Supply To Fixtures Hot The water heater must be installed according to all local and state codes or in the absence of local and state codes the National Fuel Gas Code ANSI Z223 1 NFPA 54 current edition See Labels and Installation Instructions and Use Care Guide for clearances NOTE If on a well system the expansion t...

Page 7: ...Ŷ Therm opile Pilot Figure 2 Gas Pressures Ensure that the following pressures are observed and maintained Table 1 GAS PRESSURES GAS MAXIMUM SUPPLY PRESSURE MANIFOLD GAS PRESSURE NAT 14 InWC 5 0 InWC 0 4 InWC LP 14 InWC 10 0 InWC 0 5 InWC Min Supply Pressure See Rating Plate The gas control valve thermostat also includes a temperature limiting ECO Energy Cut Off system This system will shut off th...

Page 8: ...n the thermostat setting Modern water heaters are very well insulated and retain heat so efficiently that under certain circumstances the tank water temperature can increase over time particularly when hot water is not being used This heating effect can be caused by the pilot flame itself CombusƟon Chamber with TCO Switch Combustion air is drawn through the base ring filter and flame arrestor and ...

Page 9: ...t the Igniter may not be sparking or the unit may not be getting gas or for a new installation there may still be air in the gas line Each time you click the igniter button you should be able to see the spark by looking through the view port See Figure 7 You may have to darken the room lights to see the spark You do not have to push the Control Knob in to check the Igniter button Simply look throu...

Page 10: ...n Check Repair 1 Turn the gas control valve thermostat knob to OFF 2 Wait 10 minutes for the thermopile to cool then attempt to relight the pilot by following the lighting instructions on the water heater s label NOTE This gas control valve thermostat has built in circuitry that requires waiting 10 minutes between lighting attempts Until the Thermopile reaches its normal operating temperature the ...

Page 11: ...Refer to the following list of connections when troubleshooting the system Igniter wire Figure 9 See also Testing the Igniter System on page 19 Thermopile thermal switch wires at the gas control valve thermostat Figure 9 Wire connections at the thermal switch TCO A disconnected thermal switch wire can cause the pilot to become inoperable See Figure 4 page 8 See also Diagnostic Flash Codes on page ...

Page 12: ...S THESE PLUGS WERE REMOVED FROM THE RECEPTACLE AT THE BOTTOM RIGHT HAND CORNER OF THE GAS CONTROL VALVE THERMOSTAT Figure 12 3 Follow the lighting instructions to light the pilot Once the pilot is lit continue to hold the gas control knob in until this test is complete You may need assistance from another person to do this The voltage reading should rise gradually as the thermopile heats up After ...

Page 13: ...ol valve thermostat cannot operate Remember it may take up to 90 seconds to heat the thermopile enough to power the status light 3 If you completed step 2 and the pilot will not light check for air in the gas line This is fairly common with recent work new installations If there is air in the gas line bleed the line as necessary Make sure to hold the gas control knob in fully and hold it in In mos...

Page 14: ...ter installing flow restrictors on shower heads and taking other conservation steps Undersized Water Heater If water is frequently too cool the water heater may be too small If the water heater is old the best solution may be to replace it with a larger model If the water heater is in good condition you may set the thermostat to a temperature above 120 F and install thermostatic mixing valves at e...

Page 15: ...f the water heater If the paper towel is wet after wiping a connection repair the leak s Drips from the T P Relief Valve Discharge Pipe A small amount of water dripping from the temperature and pressure T P relief valve usually means the home s water pressure is too high or you need a properly sized and pressurized thermal expansion tank A large amount of hot water coming from the T P discharge pi...

Page 16: ...de the hot and coldwaterconnectionsorthediptube cold water side Melted heat traps or a melted dip tube can restrict the flow of hot water If that s the case replace the heat traps or dip tube Partially closed supply valve Open the water heater s supply valve fully Water Odor Harmless bacteria normally present in tap water can multiply in water heaters and give off a rotten egg smell Although elimi...

Page 17: ...E d Z hddKE KEdZK V s d ZDK TAT KEdZK d DW Z dhZ EK Khd Z KKZ EKd KtE d ZDKW t Z KEE d KE D E K Z t ΈϮΉ Figure 16 Removing the Burner from the Manifold Burner Assembly Natural Gas Low Nox L P Gas Burner 1 Take off the burner by removing the two 2 screws located underneath the burner Figure 17 2 Check the burner to see if it is dirty or clogged The burner may be cleaned with soap and hot water IMPO...

Page 18: ...lve thermostat s pilot tube opening HAND TIGHT ONLY 7 Install the manifold burner assembly RED THERMAL SWITCH WIRE CONNECTIONS AT MANIFOLD DOOR Z ΈнΉ d ZD t d t Z CONNECTS TO THE GAS CONTROL VALVE THERMOSTAT t d ΈͳΉ d ZDKW WIRE CONNECTS TO THE GAS CONTROL VALVE THERMOSTAT E d Z t Z W THROUGH CENTER OF D E K KDWKE Ed K Έ D d K Ή W Kd dh W d ZKh KddKD K K D E K KDWKE Ed K Έ Z d K Ή d ZDKW t Z W d ZK...

Page 19: ...w ferrule nut in a parts kit follow these steps to connect the pilot tube A Install the ferrule nut into the gas valve at the pilot tube location hand tight only B Insert the pilot tube into the ferrule nut until the tube bottoms out then tighten the nut with a 7 16 wrench until the crimp connection seals to the pilot tube C Continue to tighten until the nut is tight in the gas valve 7 Connect the...

Page 20: ...t clockwise DO NOT OVER TIGHTEN damage may result Be sure to use approved Teflon tape or pipe joint compound on the gas piping connections and fitting on the back of the gas control valve that screws into the tank Be sure to remove the pilot ferrule nut from the new gas control valve thermostat Turn the main gas supply on and check the gas supply connections for leaks Correct any leak found Next l...

Page 21: ...on not recommended Ventilation with outside air is recommended for all installations Even if the water heater is installed in a large open room inside the house outdoor air is usually needed because modern homes are very tightly sealed and often do not supply enough air to the water heater However when installed in a large indoor space it may be possible to provide enough air without outside venti...

Page 22: ...ect to outdoors 2 Vertical ducts 3 Horizontal ducts 4 Singleopening notrecommended must be at least 100 square inches Not appropriate for confined spaces smaller than 50 cubic feet per 1 000 BTU HR as calculated in section A or when getting air from another room 5 From a larger room inside the house not recommended refer to section A above to determine if the combined volume of the rooms may be ad...

Page 23: ... OpƟons Direct to outdoors openings Figure 25 Vertical duct openings Figure 26 Horizontal duct openings Figure 27 Single opening Figure 28 ATTIC INSTALLATIONS 1 WARNING In all cases a water heater must be installed according to its installation manual Consult the local codes of your area for specific ventilation and combustion air requirements In the absence of local codes follow the National Fuel...

Page 24: ... outage may occur causing the water heater to shut down Under normal circumstances a well ventilated attic of the proper size should provide plenty of makeup air However you may need to increase ventilation if the attic is unusually tight reaches extremely high temperatures or contains more than one gas fired appliance Before doing so though check the vents to see if they are blocked If they are u...

Page 25: ...nation with one of the above factors The pressure needed to stop a flue draft is less than 1 500th of an inch of water column If the draft through the flue stops the water heater will shut down Water Damage A water heater must be installed in such a manner that if the tank or connections leak the flow will not damage the living spaces below A suitable metal drain pan should be installed under the ...

Page 26: ...ndard vent gas water heater is supplied with a specific draft hood This ensures the safe correct operation of the water heater However the draft hood must be installed correctly Do not use a draft hood other than the one that is supplied with the water heater Do not re use any previously installed draft hood Previously used parts should be discarded Do not modify cut or bend a draft hood during in...

Page 27: ...iers to flare the end of the pipe or flatten its seam joint However do not modify cut or bend the draft hood Figure 31 Figure 32 A Fit the female end of the vent pipe over the draft hood as shownbelow Notethatyoumay need to adjust or reposition the vent pipe during this process If you are connecting the draft hood to Type B vent pipe or to vent pipe of a different size or brand read the Coupling s...

Page 28: ...pipes Follow the manufacturer s instructions and all applicable code However do not use a universal adapter to join the draft hood to the vent pipe Always verify that the vent connections are secure and air tight Type B DraŌ Hood Connectors Double wall Type B vent pipe will not fit draft hoods properly To ensure a secure connection use a Type B draft hood connector between double wall vent pipe an...

Page 29: ...Residential Standard Gas Water Heater Service Handbook 29 NOTES NOTES ...

Page 30: ...30 Residential Standard Gas Water Heater Service Handbook NOTES NOTES ...

Page 31: ...Residential Standard Gas Water Heater Service Handbook 31 NOTES NOTES ...

Page 32: ...ESERVED ALL TECHNICAL AND WARRANTY QUESTIONS SHOULD BE DIRECTED TO THE LOCAL DEALER FROM WHOM THE WATER HEATER WAS PURCHASED IF YOU ARE UNSUCCESSFUL CONTACT A O SMITH WATER HEATERS RESIDENTIAL TECHNICAL ASSISTANCE AT 1 800 527 1953 OR WWW HOTWATER COM ...

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