SDT/SET Installation & Operation Manual
13
4
Domestic Side (Tank) Piping
(continued)
Temperature & Pressure (T&P) Relief Valve
For protection against excessive
temperatures and pressure, install
temperature and pressure protective
equipment required by local codes, but not
less than a combination temperature and
pressure relief valve certified by a nationally
recognized testing laboratory that maintains
periodic inspection of production of listed
equipment or materials as meeting the
requirements for Relief Valves and
Automatic Gas Shutoff Devices for Hot
Water Supply Systems, ANSI Z21.22 and the
Standard CAN1-4.4, Temperature, Pressure,
Temperature and Pressure Relief Valves and
Vacuum Relief Valves. The combination
temperature and pressure relief valve shall
be marked with a maximum set pressure not
to exceed the maximum working pressure of
the water heater. The combination
temperature and pressure relief valve shall
also have an hourly rated temperature steam
BTU discharge capacity not less than shown
in Table 4A, page 14.
Install the combination temperature and
pressure relief valve into the opening
provided and marked for this purpose on
the water heater.
WARNING
Anti-scald Valves (Mixing Valves)
Anti-scald valves used with water heaters are also called
tempering valves or mixing valves. An anti-scald valve
mixes cold water in with the outgoing hot water to assure
that hot water reaching a building fixture is at a
temperature low enough to be safe. ASSE1017 and
ASSE1070 certified valves are recommended.
Usually, the maximum temperature of the outlet water will
stay near the setting of the tank control. In some cases,
however, hot water usage patterns can cause the outlet water
temperature to rise significantly above the control setting.
The temperature of water going to the fixtures may be more
carefully controlled through the use of a thermostatic
mixing valve. This device blends a controlled amount of
cold water with the hot water leaving the tank so that water
at a more constant temperature exits the mixing valve.
Anti-scald mixing valve piping is illustrated in FIG.’s 3-1
thru 3-4.
Install Drain Valve
Drain valve and fittings are supplied by others.
Standard Installation
•
Install a tee connection at the domestic cold water
inlet (FIG. 4-1).
DRAIN
VALVE
Figure 4-1
Drain Valve Installed
WARNING
An anti-scald mixing valve does not
eliminate the risk of scalding.
*
Set the tank thermostat as low as
practical.
*
Feel water before bathing or
showering.
*
If anti-scald or anti-chill protection
is required, use devices specifically
designed for such service. Install
these devices in accordance with
their manufacturer’s instructions.
