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14

Temperature and Pressure 
Relief Valve

Explosion Hazard

If the temperature and pressure relief
valve is dripping or leaking, have a
qualified service technician replace it.

Do not plug valve.
Do not remove valve.

Failure to follow these instructions can
result in death or explosion.

Figure 15A
Temperature and Pressure
Relief Valve Installation

Discharge line 3/4" minimum
Do not cap or plug.

6" maximum

For protection against excessive pressures and 
temperatures, a temperature and pressure relief valve must 
be installed in the opening marked “T & P RELIEF VALVE” 
(see Figure 15A). This valve must be design certified by 
a nationally recognized testing laboratory that maintains 
periodic inspection of the production of listed equipment or 
materials as meeting the requirements for Relief Valves and 
Automatic Shut-off Devices for Hot Water Supply Systems, 
ANSI Z21.22. The function of the temperature and pressure 
relief valve is to discharge water in large quantities in the 
event of excessive temperature or pressure developing 
in the water heater. The valve’s relief pressure must not 
exceed the working pressure of the water heater as stated 
on the data plate.

Important:

  Only a new temperature and pressure relief 

valve should be used with your water heater. Do not use an 
old or existing valve as it may be damaged or not adequate 
for the working pressure of the new water heater. Do not 
place any valve between the relief valve and the tank.

The Temperature & Pressure Relief Valve:

• 

Must not be in contact with any electrical part.

• 

Must be connected to an adequate discharge line.

• 

Must not be rated higher than the working pressure 
shown on the data plate of the water heater.

The Discharge Line:

 

• 

Must not be smaller than the pipe size of the relief 
valve or have any reducing coupling installed in the 
discharge line.

• 

Must not be capped, blocked, plugged or contain any 
valve between the relief valve and the end of the dis-
charge line.

• 

Must terminate a maximum of six inches above a floor 
drain or external to the building.

• 

Must be capable of withstanding 250°F (121°C) without 
distortion.

• 

Must be installed to allow complete drainage of both 
the valve and discharge line.

T&P Valve and Pipe Insulation 

(Some Models)

1.  Locate the T&P Valve on the water heater. 
2.  Locate the slit running the length of the insulation.

Spread this slit open and slip it over the T&P Valve. See 
Figure 15B. Apply gentle pressure to the insulation to 
ensure it is fully seated on the T&P Valve.  Once sealed 
secure the insulation with a section of tape.
Important: The insulation or tape should not block or cover 
the T&P drain opening. Also the insulation or tape should 
not block or hinder access to the T&P valve manual relief 
lever.

4.   Next locate the hot water (outlet) & cold water (inlet) 

pipes to the water heater.  

5.  Select one of the sections of pipe insulation and locate the 

slit that runs the length of the insulation. 

6.  Spread the slit open at the base of the insulation and slip 

it over the cold water (inlet) pipe. Apply gentle 
pressure along the length of the insulation to ensure it is 
fully seated around the cold water pipe. Also ensure that 
the base of insulation is flush with the water heater. Once 
seated, secure the insulation with a section of tape.

7.  Repeat steps 5 through 6 for the hot water (outlet) pipe.

Figure 15B 
T&P Valve and Pipe Insulation 

T&P Valve

T&P Valve
Drain Line

Manual Relief Lever

T&P Insulation

Summary of Contents for 6510381

Page 1: ...med by a qualified installer service agency or the gas supplier WARNING If the information in these instructions is not followed exactly a fire or explosion may result causing property damage personal...

Page 2: ...as been under water Immediately call a qualified service technician Water heaters subjected to flood conditions or anytime the gas controls main burner or pilot have been submerged in water require re...

Page 3: ...y personnel a licensed plumber or an authorized service person Important This water heater has a resettable thermal switch installed as part of the Flame Guard Safety System DO NOT attempt to disable...

Page 4: ...led or leaked in the area of the water heater leave the area immediately and call the fire department from a neighbor s home Do not attempt to clean the spill until all ignition sources have been exti...

Page 5: ...stible materials are stated on the data plate adjacent to the gas control valve thermostat of the water heater The water heater is certified for installation on a combustible floor Important If instal...

Page 6: ...f the water heater as shown The drip leg must be no less than three inches long for the accumulation of dirt foreign material and water droplets Figure 3 Gas Piping Manual Gas Shut off Valve Ground Jo...

Page 7: ...areas Combustion air must be free of acid forming chemicals such as sulfur fluorine and chlorine These elements are found in aerosol sprays detergents bleaches cleaning solvents air fresheners paint a...

Page 8: ...an be drawn from outside of the enclosure One opening shall be within 12 inches of the top and one within 12 inches of the bottom of the enclosure as shown in Figure 4 The size of each opening free ar...

Page 9: ...supply openings consideration must be given to the blocking effect of protection louvers grilles and screens These devices can reduce airflow which in turn may require larger openings to achieve the...

Page 10: ...n existing water heater be sure to use the new drafthood supplied with the water heater Figure 9 Drafthood Installation Sheet Metal Screws four provided Drafthood Jacket top Install the drafthood with...

Page 11: ...erms of its listing It must be connected to the water heater s drafthood by a certified vent connector or by directly originating at the drafthood opening Vertical gas vents must terminate with a list...

Page 12: ...ine as shown in Figure 14 These valves reduce the point of use temperature of the water by mixing cold and hot water and are readily available for use 4 If installing the water heater in a closed wate...

Page 13: ...s DO NOT add any chemicals to the system piping which will contaminate the potable water supply Closed System Thermal Expansion Periodic discharge of the temperature and pressure relief valve may be d...

Page 14: ...higher than the working pressure shown on the data plate of the water heater The Discharge Line Must not be smaller than the pipe size of the relief valve or have any reducing coupling installed in th...

Page 15: ...the system Otherwise these bubbles will be trapped in the air handler heat exchanger coil reducing the efficiency Do not connect the water heater to any system or components previously used with non...

Page 16: ...reduce the likelihood of a flammable vapor ignition incident New technology used in meeting these standards makes this product less tolerant of installation errors or improper installation environmen...

Page 17: ...with the igniter repeat steps 4 7 Continue to hold the button for about 1 minute after the pilot is lit Release the reset button and it will pop back up Pilot should remain lit If the pilot light goe...

Page 18: ...r Temperature Regulation UNITROL BEFORE LIG HTIN G READ ALL IN STRUCTIO NS CAUTIO N H O T W A R M V A C A T I O N CAUTION W A TER INCREAS E S HOTTER T H E RISK OF SCALD INJ U R Y V A C A T I O N WAR M...

Page 19: ...rt on page 26 Reset the thermal switch by depressing the small button in the center of the thermal thermal switch Important Correct any issues prior to resetting the thermal switch DO NOT attempt to d...

Page 20: ...age or deterioration in the venting system Make sure the ventilation and combustion air supplies are not obstructed Build up of soot and carbon on the main burner and pilot burner Check for a soft blu...

Page 21: ...to see if it is dirty or clogged The burner may be cleaned with soap and hot water Figure 24 N O T W A H S T R E B O R I A C A V M R A W U T O H T H E R I SK OF Y R U J N I D L A C S R E T T O H W A...

Page 22: ...ly Page 23 Figure 25 Two Piece Wire Connector Assembly Two Piece Wire Connector Thermocouple Retainer Clip Manifold Door Other fittings not shown for clarity Pilot T ube Igniter Wire Figure 26 Thermoc...

Page 23: ...lve for leaks Test the supply connections by brushing on an approved noncorrosive leak detection solution Bubbles forming indicate a leak Correct any leak found 9 Follow the lighting instructions on p...

Page 24: ...ant The gas control valve thermostat is a standard valve with wire leads that connect to a thermal switch Removing the Gas Valve 1 On the gas control valve thermostat turn the temperature dial counter...

Page 25: ...te 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 an...

Page 26: ...nstructions section of this manual for specific requirements NO Is the pilot tube damaged NO Does the flame trap show signs of discoloration and or debris Shut off the gas supply to the water heater a...

Page 27: ...y System parts Item No Parts Description 1 DRAFTHOOD 2 REDUCER RING SOME MODELS 3 FLUE BAFFLE 4 HEAT TRAP COLD SOME MODELS 5 HEAT TRAP HOT SOME MODELS 6 COLD WATER DIP TUBE 7 ANODE ROD 8 TEMPERATURE P...

Page 28: ...e wire connector with retainer clip thermal switch and pilot assembly Natural Gas Low Nox Item 17 Manifold door assembly which contains the manifold tube gasket door pilot tube thermocouple two piece...

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