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.