17
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. 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.
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 18.
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 19. Apply gentle pressure to
the insulation to ensure that it is fully seated on the
T&P Relief Valve. Once seated, secure the insulation
with duct tape.
IMPORTANT:
The insulation or tape should not block
or cover the T&P relief valve drain opening. Also, the
insulation or tape should not block or hinder access to
the manual relief lever (Figure 19).
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 that it is fully seated
around the pipe. Also, ensure that the base of the
insulation is flush with the water heater. Once seated,
secure the insulation with duct tape.
7. Repeat steps 5 and 6 for the hot water (outlet) pipe.
8. Add additional sections of pipe insulation as needed.
T&P RELIEF VALVE
T&P RELIEF VALVE
MANUAL RELIEF LEVER
T&P RELIEF VALVE INSULATION
FIGURE 19.
Temperature and Pressure Relief Valve
Explosion Harzard
• 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.
6” MAXIMUM
AIR GAP
METAL
DRAIN PAN
DISCHARGE PIPE
(DO NOT CAP OR PLUG)
TEMPERATURE AND PRESSURE (T&P)
DRAIN LINE
3/4” ID
MINIMUM
DRAIN
1” MINIMUM
FIGURE 18.
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 17). 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.
