Instructions / Assembly

lp-547 Rev. 1.29.16
7
B. Thermal Expansion
2. Connect the hot water line to the connection marked “HOT”
on the top of the water heater.
3. Install the T&P Valve in the opening provided near the top
of the heater.
4. Install drain valve in the opening provided near the bottom
of the heater.
A check valve may be installed in the cold water inlet line as
a separate backow preventer, or may be part of a pressure
reducing valve, water meter, or water softener. An “open
water system” refers to a system without a check valve. A
“closed water system” refers to a system with a check valve
installed in the cold water inlet line.
As water is heated, it expands in volume and increases
pressure within the water system. This action is referred to
as “thermal expansion”. In an open water system, expanding
water which exceeds the capacity of the system ows back
into the city main where pressure is easily dissipated.
A closed water system prevents expanding water from
owing back to the city main. The resulting thermal expansion
can rapidly increase pressure in the water heater and system
piping. This rapid pressure increase can exceed the setting
of the pressure relief valve, causing it to operate during each
heating cycle, resulting in discharge from the T&P. This rapid
and repeated expansion and contraction of components in the
system can cause premature failure of system components,
including the relief valve and possibly the water heater.
Replacing the relief valve will not correct thermal expansion.
A potable hot water expansion tank is required to oset
thermal expansion. Expansion tanks are designed with an air
cushion built in that compresses as system pressure increases,
thereby relieving the overpressure condition and eliminating
repeated operation of the relief valve. This expansion tank
should be installed in the cold water line between the water
heater and check valve, and must be sized for the entire water
volume of the hot water system. See piping Applications.
Other methods of controlling thermal expansion are
available. Check with the local water utility to determine if
a check valve exists in the cold water inlet line. Contact your
installing contractor, water supplier, or plumbing inspector for
additional information regarding thermal expansion.
C. Condensation
Condensation can form on the water heater when it is rst
lled with water, and may also occur with a heavy water draw
and very cold inlet water temperature. This condition is not
unusual and will disappear as the water becomes heated.
However, if the condensation should continue, examine the
piping and ttings for possible leaks.
D. Insulation Blankets
If local codes require external application of insulation blanket
kits, the manufacturer’s instructions included with the kit must
be carefully followed.
In addition, pay careful attention to the following so as not to
restrict the proper function and operation of the water heater:
• Do not cover the operating or warning labels attached
to the water heater or attempt to locate them on the
exterior of the insulation blanket.
• Do not apply insulation to the top of the water heater.
This could interfere with the safe operation of the
electrical junction box.
• Do not cover the jacket access panel(s) to the
thermostat(s) and heating element(s) or T&P valve.
• Inspect the insulation blanket frequently.
Failure to follow these instructions could result in property
damage, severe personal injury, or death.
E. Temperature and Pressure Relief Valve
For protection against excessive pressures and temperatures in
this water heater, install temperature and pressure protective
equipment as required by local codes, but not less than a
combination T&P valve meeting the requirements for Relief
Valves and Automatic Gas Shuto Devices for Hot Water Supply
Systems, ANSI Z21.22B / CSA 4.4-M99 by a nationally recognized
testing laboratory that maintains periodic inspection of
production listed equipment and materials. This valve must be
marked with a maximum set pressure not to exceed the marked
maximum working pressure of the water heater. Install the T&P
valve into the opening provided and marked for this purpose
on the water heater. The T&P valve must be plumbed down
so discharge can exit at least 6” above the structural oor. The
relief line cannot be in contact with any live electrical parts.