American Water Heater 317994-002 Manual De Usuario

17

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 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 rating 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 rating plate of the water heater.

 

• 

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. In cold climates, it is 

recommended that the discharge pipe be terminated at  

an adequate drain inside 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.

1.  Locate the temperature and relief valve on the water 

heater (also known as a T&P Relief Valve, Figure 15B). 

2.  Locate the slit running the length of the insulation.
3  Spread this slit open and slip it up under the T&P Relief 

Valve. See Figure 15B. Apply gentle pressure to the 
insulation to ensure it is fully seated on the T&P Relief 
Valve.  Once sealed secure the insulation with a section 
of duct tape, electrical tape, or equivalent.
IMPORTANT: The insulation or tape must not block the 
discharge opening or hinder access to the manual relief 
lever. Ensure a discharge pipe is installed into the T&P 
valve discharge opening per the instructions manual.

4.  Locate the hot water (outlet) & cold water (inlet) pipes to 

the water heater.  

5.  Locate the slit running the length of a section of pipe 

insulation. 

6.  Spread the slit open and slip the insulation over the cold 

water (inlet) pipe. Apply gentle pressure along the length 
of the insulation to ensure it is fully seated around the 

pipe. Also ensure that the base of insulation is flush with 
the water heater. Once seated, secure the insulation with 
duct tape, electrical tape, or equivalent.

7.  Repeat steps 5 through 6 for the hot water (outlet) pipe.
8.  Add additional sections of pipe insulation as needed.

T&P Relief Valve Insulation

Manual Relief Lever

T&P Relief Valve

T&P Relief Valve
Drain Line

Some water heater models are equipped with inlet/outlet 

connections for use with space heating applications. If this 

water heater is to be used to supply both space heating 

and domestic potable (drinking) water, the instructions 

listed below must be followed.
• 

Be sure to follow the manual(s) shipped with the air 

handler system.

• 

This water heater is not to be used as a replacement 

for an existing boiler installation.

• 

Do not use with piping that has been treated with 

chromates, boiler seal or other chemicals and do not 

add any chemicals to the water heater piping.

• 

If the space heating system requires water 

temperatures in excess of 120°F, a mixing valve 

or an anti-scald device should be installed per its 

manufacturer’s instructions in the domestic (potable) 

hot water supply to limit the risk of scald injury.

• 

Pumps, valves, piping and fittings must be compatible 

with potable water.

• 

A properly installed flow control valve is required to 

prevent thermosiphoning. Thermosiphoning is the 

result of a continuous flow of water through the air 

handler circuit during the off cycle. Weeping (blow off) 

of the temperature and pressure relief valve (T & P) 

or higher than normal water temperatures are the first 

signs of thermosiphoning.

• 

The domestic hot water line from the water heater 

should be vertical past any mixing valve or supply line to 

the air handler to remove air bubbles from 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-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  heated  water.