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26

Removing and Replacing the Gas 
Control Valve/Thermostat

IMPORTANT:

 The gas control valve/thermostat is a standard 

valve with wire leads that connect to a thermal switch. 
Removing the Gas Control Valve/Thermostat:
1.  Turn the gas control/temperature knob  to the “OFF” 

position (Figure 19A).

2.  Turn off the gas at the manual shut-off valve on the gas 

supply pipe (Figure 3).

3.  Drain the water heater. Refer to the section of “Draining 

and Flushing” and follow the procedure.

4.  Disconnect the igniter wire from the igniter lead wire. Use 

needle nose pliers to disconnect the red (+) and white (-)  

thermopile wires.  Disconnect  pilot tube (7/16” wrench) 

and manifold tube (3/4” wrench) at the gas control valve/

thermostat  (Figure 22).  

NOTE:

 L.P. Gas systems use 

reverse (left-hand) threads on the manifold tube.

5.  Refer to “Gas Piping” (Figure 3) and disconnect the 

ground joint union in the gas piping. Disconnect the 

remaining pipe from the gas control valve/thermostat.

6.  To remove the gas control valve/thermostat, thread a 4” 

section of gas pipe into the inlet and use it to turn the 

Flame Lock

®

 Safety System Operational Checklist

TROUBLESHOOTING CHART

gas control valve/thermostat (counterclockwise.) Do not 

use pipe wrench or equivalent to grip body.  Damage 

may result, causing leaks. Do not insert any sharp 

objects into the inlet or outlet connections. Damage to 

the gas control valve/thermostat may result.

Gas Control Valve/Thermostat:
To replace the gas control valve/thermostat, reassemble 

in reverse order. When replacing the gas control valve/

thermostat, thread a 4” section of gas pipe into the inlet and 

use it to turn the gas control valve/thermostat (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 tank.

• 

Be sure to remove the pilot ferrule nut from the new gas 

control valve/thermostat.

• 

Turn the gas supply on and check for leaks. Test the 

water heater by brushing on an approved noncorrosive 

leak detection solution. Bubbles forming indicate a leak. 

Correct any leak found. 

• 

Be sure tank is completely filled with water before 

lighting and activating the water heater. Follow the 

“Lighting Instructions” on page 17.

• 

If additional information is required, contact the Service

 

Department at: 1-877-817-6750.

5.  No leaks at pilot and manifold connection.
6.  Manifold door screws securely tightened. 
7.  Depress the button on the thermal switch.          
       

1.  Manifold gasket properly sealed.
2.  Viewport not damaged or cracked.
3.  Flame-trap free of debris and undamaged.
4.  Manifold component block properly installed.

PROBLEM

POSSIBLE CAUSE(S)

CORRECTIVE ACTION

BURNER WILL NOT IGNITE

1.  Pilot not lit

2.  Thermostat set too low

3. No 

gas

4.  Dirt in the gas lines

5.  Pilot line clogged

6.  Main burner line clogged

7. Non-functioning 

thermopile

8. Non-functioning 

thermostat

9.  Heater installed in a confined area

1. Light 

pilot

2.  Turn temp. dial to desired temperature

3.  Check with gas utility company

4.  Notify utility-install trap in gas line

5.  Clean, locate source and correct

6.  Clean, locate source and correct

7. Replace 

thermopile

8. Replace 

thermostat

9.  Provide fresh air ventilation

SMELLY WATER

1.  Sulfides in the water

1.  Replace the anode with a special anode

BURNER FLAME YELLOW-

LAZY

1.  Insufficient secondary air

2.  Low gas pressure

3. Flue 

clogged

4.  Main burner line clogged

5.  Heater installed in a confined area

6.  Obstruction in main burner orifice

1.  Provide ventilation to water heater

2.  Check with gas utility company

3.  Clean, locate source and correct

4.  Clean, locate source and correct

5.  Proper fresh air ventilation

6.  Clean or replace orifice

PILOT WILL NOT LIGHT OR 

REMAIN LIT

1. Non-functioning 

igniter

2.  The thermal switch tripped

3.  Thermopile connection loose

4.  Air in gas line

5.  Proper Lighting Sequence not followed.  

Gas Control / Temperature Knob was not 

held in for sufficient time.

6.  Low gas pressure

7. No 

gas

8.  Dirt in gas lines

9. Cold 

drafts

10.  Thermostat ECO switch open

1.  Replace igniter pilot assembly

2.  See Pilot Light Troubleshooting Flowchart

section

3.  Seat connector firmly in socket

4.  Bleed the air from the gas line

5.  Do not attempt to relight if the red light is lit 

and the pilot flame is not visible through the 

view port.  Wait until the red light is no longer 

lit, then follow lighting instructions on the water 

heater.

6.  Check with gas utility company

7.  Check with gas utility company

8.  Notify utility-install dirt trap in gas line

9.  Locate source and correct

10. Replace thermostat

Summary of Contents for NU30T61-303

Page 1: ...explosion may result causing property damage personal injury or death INSTALLER AFFIX THESE INSTRUCTIONS TO OR ADJACENT TO THE WATER HEATER OWNER RETAIN THESE INSTRUCTIONS AND WARRANTY FOR FUTURE REFERENCE RETAIN THE ORIGINAL RECEIPT AS PROOF OF PURCHASE Table of Contents 2 318051 002 October 2010 Residential Gas Water Heater with the Flame Lock Safety System To obtain technical warranty or servic...

Page 2: ...followed Important Instructions Do not use this appliance if any part has been under water Immediately call a qualified person Water heaters sub jected to flood conditions or any time the gas controls main burner or pilot have been submerged in water require replacement of the entire water heater Hydrogen gas can be produced in a hot water system that has not been used for a long period of time ge...

Page 3: ... You or future users of this water heater will need it for future reference Service to the Flame Lock Safety System should only be performed by a qualified person Examples of a qualified person include licensed plumbers authorized gas company personnel and authorized service personnel IMPORTANT The manufacturer and seller of this water heater will not be liable for any damages injuries or deaths c...

Page 4: ...hese instructions and or an inadequate air supply can cause the Flame Lock Safety System to disable the water heater Please make required installation and venting air supply changes prior to resetting the system see Combustion Air Supply and Ventilation section IMPORTANT This water heater has a resettable thermal switch installed as part of the Flame Lock Safety System Do not attempt to disable or...

Page 5: ...ssible for operation and service Maintain proper clearances as specified on the data plate Do not locate the water heater near an air moving device The operation of air moving devices such as exhaust fans ventilation systems clothes dryers fireplaces etc can affect the proper operation of the water heater Special attention must be given to conditions these devices may create Flow reversal of flue ...

Page 6: ... height Figure 3 Gas Piping Gas Pressure IMPORTANT The gas supply pressure must not exceed the maximum supply pressure as stated on the water heater s data plate The minimum supply pressure is for the purpose of input adjustment Gas Pressure Testing IMPORTANT This water heater and its gas connection must be leak tested before placing the appliance in operation If the code requires the gas lines to...

Page 7: ...fresheners paint and varnish removers refrigerants and many other commercial and household products When burned vapors from these products form highly corrosive acid compounds These products should not be stored or used near the water heater or air inlet Combustion and ventilation air requirements are determined by the location of the water heater The water heater may be located in either an open ...

Page 8: ...nput of all gas utilization equipment i e water heaters furnaces clothes dryers etc and the method by which the air is provided The BTU HR input can be found on the water heater data plate Additional air can be provided by two methods 1 All air from inside the building 2 All air from outdoors Figure 4 Opening Locations Confined Spaces 12 maximum Permanent openings to the outside or additional room...

Page 9: ...e opened automatically during equipment operation Keep louvers and grilles clean and free of debris or other obstructions Table 3 Minimum Free Area of Permanent Openings for Ventilation and Combustion Air Supply All Air from Outdoors Only Based on the total BTU HR input rating for all utilizing equip ment within the confined space Opening Source Minimum Free Area Per Opening sq in Reference Drawin...

Page 10: ...r sizing a vent pipe system If a transition to a larger vent size is required the vent transition connection must be made at the draft hood outlet Vent Connectors 1 Type B Double wall U L Listed Vent Pipe 2 Single wall Vent Pipe Maintain the manufacturer s specified minimum clearance from combustible materials when using type B double wall vent pipe Vent connectors made of type B double wall vent ...

Page 11: ...s 11 and 12 IMPORTANT This gas vent must be terminated in a vertical position to facilitate the removal of the burnt gases An unused chimney flue or masonry enclosure may be used as a passageway for the installation of a gas vent Figure 12 Common combined venting is allowable with vertical type B vent systems and lined masonry chimneys as long as proper draft for the water heater is established un...

Page 12: ...ture of the water by mixing cold and hot water and are readily available for use 4 If installing the water heater in a closed water system install an expansion tank in the cold water line as specified under Closed System Thermal Expansion section 5 Install a shut off valve in the cold water inlet line It should be located close to the water heater and be easily accessible Know the location of this...

Page 13: ...erson include licensed plumbers authorized gas company personnel and authorized service personnel Do not plug valve Do not remove valve Failure to follow these instructions can result in death or explosion WARNING As water is heated it expands thermal expansion In a closed system the volume of water will grow As the volume of water grows there will be a corresponding increase in water pressure due...

Page 14: ...installed to allow complete drainage of both the valve and discharge line T P Relief Valve and Pipe Insulation Some Models 1 Locate the temperature and pressure relief valve on the water heater also known as a T P relief valve See Figure 15B 2 Locate the slit running the length of the T P relief valve insulation 3 Spread the slit open and fit the insulation over the T P relief valve See Figure 15B...

Page 15: ...exchanger coil reducing the efficiency Do not connect the water heater to any system or components previously used with non potable water heating appliances when used to supply potable water Some jurisdictions may require a backflow preventer in the incoming cold water line This may cause the temperature and pressure relief valve on the water heater to discharge or weep due to expansion of the hea...

Page 16: ...authorized service provider Fresh air supply free of corrosive elements and flammable vapors Fresh air openings sized correctly with consideration given to the blocking effect of louvers and grilles Ductwork is the same cross sectional area as the openings Vent Pipe System Check for proper drafting at the water heater draft hood Refer to the Checking the Draft section of this manual for the test p...

Page 17: ... the air intake grid bottom of combustion chamber and require replacement of the entire water heater WARNING If you do not follow these instructions exactly a fire or explosion may result causing property damage personal injury or loss of life TO TURN OFF GAS TO APPLIANCE 1 Turn the gas control temperature knob counterclockwise to the OFF setting The status light will stop blinking and stay on for...

Page 18: ...8 Flame Characteristics Tips may have a yellow tint Yellow inner cones are satisfactory Correct flame soft blue Burn Hazard Do not touch vent Doing so can result in burns WARNING Burner Flames Inspect the burner flames through the viewport and compare them to the drawings in Figure 18 A properly operating burner should produce a soft blue flame Blue tips with yellow inner cones are satisfactory Th...

Page 19: ...ain threshold 35 minutes 1 minute 5 seconds 2 seconds 1 second instantaneous 45 minutes 5 minutes 25 seconds 5 seconds 2 seconds 1 seconds U S Government Memorandum C P S C Peter L Armstrong Sept 15 1978 VAC Figure 19A Gas Control Valve Thermostat Settings Gas Control Temperature Knob Status Light Igniter 120 F Mark NOTE During low demand periods when hot water is not being used a lower thermostat...

Page 20: ... Setting The controller adjusts the water temperature to approximately 55 F This setting is recommended when the water heater is not in use for a long period of time This effectively turns the water heater down to a setting that prevents the water from freezing Status Light Code Normal Flashes 0 Flashes Indicates Control Off Pilot Out 1 Flash Indicates Normal Operation Continuous Light indicates t...

Page 21: ...setting the switch Contact the Product Service and Support Department for service information at 1 877 817 6750 A temperature limit switch or ECO Energy Cut Off sensor located in the gas control valve thermostat is used to shut off the water heater if the water temperature exceeds 189 F 87 C for 155 F models or 199 F 93 C for 180 F models See the data plate for your model The Diagnostic Status Lig...

Page 22: ...rner and pilot burner Check for a soft blue flame Leaking or damaged water and gas piping Presence of flammable or corrosive materials in the installation area Presence of combustible materials near the water heater After servicing this water heater check to make sure it is working properly See Operating Your Water Heater section of this manual IMPORTANT If you lack the necessary skills required t...

Page 23: ... Burner from the Manifold Assembly Natural Gas Burner Low Nox L P Burner 1 Take off the burner by removing the two 2 screws lo cated underneath the burner 2 Check the burner to see if it is dirty or clogged The burner may be cleaned with soap and hot water Figure 24A Igniter Wire Red Wire Left Side Pilot Tube Manifold Tube Igniter Button Figure 22 Gas Control Valve Thermostat Igniter Lead Wire Whi...

Page 24: ...res through the top opening of the manifold component block Figure 25 Be sure the igniter wire is positioned through the middle opening of the manifold component block 11 See Replacing Manifold Assembly Page 25 Filter Installation and Cleaning IMPORTANT It is essential that the filter be installed properly If you encounter difficulty installing the filter or have a question please call the Service...

Page 25: ...n is pressed See Figure 29 Use only factory authorized piezoelectric igniter parts for replacement Testing the Igniter System Turn off the gas to the water heater at the manual gas shut off valve Watch the electrode tip while activating the igniter A visible spark should jump from the electrode To avoid shock do not touch the burner or any metal part on the pilot or pilot assembly If no spark is v...

Page 26: ... lighting and activating the water heater Follow the Lighting Instructions on page 17 If additional information is required contact the Service Department at 1 877 817 6750 5 No leaks at pilot and manifold connection 6 Manifold door screws securely tightened 7 Depress the button on the thermal switch 1 Manifold gasket properly sealed 2 Viewport not damaged or cracked 3 Flame trap free of debris an...

Page 27: ... way flue baffle and burner 2 Clean flue locate source and correct 3 Check with gas utility company 4 Replace thermostat 5 Turn temperature dial to desired setting 6 Install adequate heater 7 Correct piping dip tube must be in cold inlet 8 Advise customer DRIP FROM RELIEF VALVE 1 Excessive water pressure 2 Heater stacking 3 Closed water system 1 Use a pressure reducing valve and relief valve 2 Low...

Page 28: ...ES This condition only appears if the gas control temperature knob has been turned off and the thermopile continued to produce electric power This condition can occur if the thermopile does not cool down as quickly as expected when the unit is shut off This condition can also occur if the gas control temperature knob has been turned off and the pilot continues to operate because the pilot valve is...

Page 29: ...rigeration authorized service provider to correct the combustion air supply ventilation issue Correct size of openings to allow sufficient air NO YES YES YES NO Check the vent system for restrictions obstructions and check the vent termination height Refer to the Installation Instructions section of this manual for specific requirements NO Section C Pilot light will not remain lit Contact Customer...

Page 30: ...OPILEASSEMBLY KIT 12B PILOT THERMOPILEASSEMBLY KIT L P Cast Burner 13A BURNER Natural Gas Low Nox 13B L P CAST BURNER 14A MANIFOLD DOOR ASSEMBLY 14B MANIFOLD DOOR ASSEMBLY L P Cast Burner 15 MANIFOLD COMPONENT BLOCK 16 MANIFOLD DOOR GASKET 17 VIEWPORT ASSEMBLY Pictured on next page When ordering repair parts always give the following information 1 Model serial and product number 2 Type of gas 3 It...

Page 31: ...h contains the manifold tube gasket door pilot tube thermopile manifold component block with retainer clip thermal switch and pilot assembly Natural Gas Low Nox Item 14 Manifold door assembly which contains the manifold tube gasket door pilot tube thermopile manifold component block with retainer clip thermal switch and pilot assembly L P Gas Item 15 Contains manifold component block and retainer ...

Page 32: ... Registered trademark TM Trademark of Whirlpool U S A 2010 Whirlpool Corporation All rights reserved Manufactured under license by American Water Heater Company Tennessee Warranty provided by Manufacturer ...

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