John Wood Atmospheric Gas (Standard) - Manual (Page 15)

15
Piping Installation
Piping, fittings, and valves should be installed according to
the installation drawing (Figure 11). If the indoor installation
area is subject to freezing temperatures, the water piping
must be protected by insulation.
The water supply pressure should not exceed 80 psi
(551.58 kPa). If this occurs, a pressure reducing valve
with a bypass should 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
cold water inlet fitting. Connect the hot water supply
(3/4” NPT) to the hot water outlet fitting.
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 mixing valve or an anti-scald device in the
domestic hot water line as shown in Figure 12. 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.
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.
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.
WATER SYSTEM PIPING
METAL
DRAIN PAN
1 3/4” DEPTH MAXIMUM
FLOOR DRAIN
DRAIN LINE 3/4”
ID MINIMUM
DISCHARGE PIPE
DO NOT CAP OR PLUG
TEMPERATURE AND PRESSURE RELIEF VALVE
IN A CLOSED SYSTEM, USE A
THERMAL EXPANSION TANK
COLD WATER
SUPPLY TO FIXTURES
COLD WATER
INLET VALVE
(SHUT-OFF VALVE)
PRESSURE REDUCING
VALVE WITH BYPASS
UNION
HOT WATER
OUTLET
MAIN WATER SUPPLY
1” (2.54 cm)
MINIMUM
12” (300 mm)
MAXIMUM AIR GAP
FIGURE 11.
COLD
WATER
INLET
HOT
WATER
OUTLET
TEMPERED WATER
TO FIXTURES
MIXING VALVE
(SET TO 120°F/
48.89°C)
FOLLOW THE MIXING
VALVE MANUFACTURER’S
INSTRUCTIONS
UNTEMPERED
HOT WATER
FIGURE 12.
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.
(Continued.)