12
Water System Piping

Piping Installation

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.
IMPORTANT: 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
fittings.
IMPORTANT: Always use a good grade of joint compound
and be certain that all fittings are drawn up tight.
1. 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 traps.
2. 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.
3. 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.
4. 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”
(Page 13).
5. 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.
6. 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,” page 13.
7. 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.
1” Minimum
Metal
Drain Pan
1 3/4” depth maximum Drain
Drain line
3/4” ID
minimum
Discharge line
6” maximum
above drain
Temperature and
Pressure Relief Valve
In a closed system use a
thermal expansion tank
Cold Water
Supply to Fixtures
Cold Water
Inlet Valve
Pressure reducing
valve with bypass
Union
Hot Water
Outlet
Massachussetts:
Install a vacuum relief
in cold water line per
section 19 MGL 142.
Figure 13
Water Piping Installation
Main water supply
Figure 14
Typical Tempering
Valve Installation
Follow the tempering
valve manufacturer’s
instructions.
Cold
Water
Inlet
Hot
Water
Outlet
Tempered water
to fixtures
Tempering valve
(Set to 120°F)
Please note the following:
• The system should be installed only with piping that is
suitable for potable (drinkable) water such as copper,
CPVC, or polybutylene. This water heater must not be
installed using iron piping or PVC water piping.
• Use only pumps, valves, or fittings that are compatible
with potable water.
• Use only full flow ball or gate valves. The use of valves
that may cause excessive restriction to water flow is
not recommended.
• Use only 95/5 tin-antimony or other equivalent solder.
Any lead based solder must not be used.
• Piping that has been treated with chromates, boiler
seal, or other chemicals must not be used.
• Chemicals that may contaminate the potable water
supply must not be added to the piping system.