Water System Piping
Piping, fittings, and valves should be installed according to
the installation drawing (Figure 13). If the indoor installation
area is subject to freezing temperatures, the water piping
must be protected by insulation.
Water supply pressure should not exceed 80% of the
working pressure of the water heater. The working
pressure is stated on the water heater's data plate. If this
occurs, a pressure limiting valve with a bypass may need
to be installed in the cold water inlet line. This should
be placed on the supply to the entire house in order to
maintain equal hot and cold water pressures.
Heat cannot be applied to the water fittings on the
heater as they may contain nonmetallic parts. If solder
connections are used, solder the pipe to the adapter
before attaching the adapter to the hot and cold water
Always use a good grade of joint compound and be
certain that all fittings are drawn up tight.
Install the water piping and fittings as shown in Figure
13. Connect the cold water supply (3/4" NPT) to the
fitting marked "C". Connect the hot water supply (3/4"
NPT) to the fitting marked "H".
IMPORTANT: Some models may contain energy saving
heat traps to prevent the circulation of hot water within
the pipes. Do not remove the inserts within the heat
The installation of unions in both the hot and cold water
supply lines is recommended for ease of removing the
water heater for service or replacement.
Some local codes may require, and the manufacturer
of this water heater recommends, installing a tempering
valve or an anti-scald device in the domestic hot water
line 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.
If installing the water heater in a closed water system,
install an expansion tank in the cold water line as
specified under "Closed System/Thermal Expansion"
Install a shut-off valve in the cold water inlet line. It
should be located close to the water heater and be
easily accessible. Know the location of this valve and
how to shut off the water to the heater.
A temperature and pressure relief valve must be
installed in the opening marked "Temperature and
Pressure (T & P) Relief Valve" on the water heater.
A discharge line must be added to the opening of
the T&P Relief Valve. Follow the instructions under
"Temperature and Pressure Relief Valve" section.
After piping has been properly connected to the water
heater, remove the aerator at the nearest hot water
faucet. Open the hot water faucet and allow the tank
to completely fill with water. To purge the lines of
any excess air, keep the hot water faucet open for
3 minutes after a constant flow of water is obtained.
Close the faucet and check all connections for leaks.
Water Piping Installation
In a closed system use a
' expansion tank
^- Cold Water
Supply to Fixtures
valve with bypass
Drain Pan X
1 3/4" depth maximum
Pressure Relief Valve
Install a vacuum relief
in cold water line per
section 19 MGL 142.
Follow the tempering