John Wood Commercial - AJWSC - Manual (Page 13)

For example, a top inlet connection must use a top outlet
connection.
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. Since most commercial installations utilize higher tem-
peratures, the use of a tempering valve is strongly
recommended in all domestic hot water lines (i.e.
public restroom sinks, etc).
4. If installing the water heater in a closed water system,
install an expansion tank in the cold water line as spec-
ified 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 eas-
ily accessible. The owner/operator must be shown the
location of this valve and be given instructions on how
to use it to shut off the water to the heater.
6. The water heater is shipped with a factory-installed
Temperature and Pressure Relief Valve. Install a dis-
charge line in the opening in the T&P 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.
Tempering Valve Installation
A Tempering Valve should be installed per the manufactur-
er’s instructions in the hot water line. See Figure 8 for sam-
ple tempering valve installation.
Please note the following:
DO NOT install this water heater with iron piping. The sys-
tem should be installed only with piping that is suitable for
potable (drinkable) water such as copper, CPVC, or poly-
butylene. DO NOT use PVC water piping.
DO NOT use any pumps, valves, or fittings that are not
compatible with potable water.
DO NOT use valves that may cause excessive restriction to
water flow. Use full flow ball or gate valves only.
DO NOT use any lead based solder on potable water lines.
Use appropriate tin-antimony or other equivalent material.
DO NOT tamper with the integrated control, gas valve, ignit-
er or temperature and pressure relief valve. Tampering
voids all warranties. Only qualified service technicians
should service these components.
DO NOT use with piping that has been treated with chro-
mates, boiler seal, or other chemicals.
DO NOT add any chemicals to the system piping which will
contaminate the potable water supply.
Closed System/Thermal Expansion
Periodic discharge of the temperature and pressure relief
valve may be due to thermal expansion in a closed water
supply system. The water utility supply meter may contain a
check valve, backflow preventer or water pressure reducing
valve. This will create a closed water system. During the
heating cycle of the water heater, the water expands caus-
ing pressure inside the water heater to increase. This may
cause the temperature and pressure relief valve to dis-
charge small quantities of hot water. To prevent this, it is
recommended that a diaphragm-type expansion tank (suit-
able for potable water) be installed on the cold water supply
line. The expansion tank must be properly sized for the
application. Contact the local water supplier or plumbing
inspector for information on other methods to control this sit-
uation.
Important: Do not plug or remove the temperature and
pressure relief valve.
Temperature and Pressure (T&P) Relief Valve
For protection against excessive pressures and tempera-
tures, a temperature and pressure relief valve must be
installed in the opening marked “T&P RELIEF VALVE” (see
Figure 9). This valve must be design certified by a national-
ly recognized testing laboratory that maintains periodic
inspection of the production of listed equipment or materials
as meeting the requirements of the “Standard For Relief
Valves For Hot Water Supply Systems”, ANSI
Z21.22/CSA 4.4”. The function of the temperature and pres-
sure relief valve is to discharge water in large quantities in
the event of excessive temperature or pressure developing
in the water heater. The valve’s relief pressure must not
exceed the working pressure of the water heater as stated
on the data plate.
Follow the tempering
valve manufacturer’s
instructions.
Cold
Water
Inlet
Hot
Water
Outlet
Tempered water
to fixtures
Tempering valve
(Set to 120°F)
Figure 8 Tempering Valve
WARNING
Explosion Hazard
• If the temperature and pressure relief
valve is dripping or leaking, have a
licensed plumber repair it.
• Do not plug valve.
• Do not remove valve.
• Failure to follow these instructions can
result in death or an explosion.
– 13 –