lp-772 Rev. 000 Rel. 000 Date 3.17.21
7
C. Thermal Expansion
Dielectric fittings must be used on water connections.
A check valve may be installed in the cold water inlet line as a separate
backflow 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 flows back into the city main where pressure is easily
dissipated.
A closed water system prevents expanding water from flowing 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 offset 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.
A. Plumbing
It is mandatory that all plumbing be done in accordance with
federal, local, and state plumbing codes and practices. Failure to
properly install the water heater WILL VOID the warranty. It is also
necessary to use both thread tape and pipe sealing compound on
all mechanical plumbing connections.
It is recommended to use unions on the hot and cold water
connections to easily disconnect the water heater for servicing.
Part 3 - Piping
D. Condensation
Condensation can form on the water heater when it is first filled 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 fittings for possible leaks.
E. 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 to the thermostat and
heating element or T&P valve.
•
Inspect the insulation blanket frequently.
Failure to follow these instructions could result in property damage,
severe personal injury, or death.
Do not apply heat to the Hot or Cold water heater connections. If
sweat connections are used, sweat tubing to the adapter before
fitting adapter to the water connections on the heater. Any
heat applied to the water heater connections will permanently
damage the dip tube and/or heat traps. Damages due to improper
installation practices ARE NOT covered by warranty.
Do not disturb the factory seal on the water heater connections!
Use two wrenches when tightening or loosening the piping, valve,
or adapters at the water heater. One to secure the water heater
fitting, the other to tighten or loosen connections to the water
heater. DO NOT over-tighten!
The water connections must be installed in accordance with all local
and national plumbing codes, or any applicable standard which
prevails.
• Pipe material must be suitable to meet local codes and industry
standards.
• The pipe must be cleaned and without blemish before any
connections are made.
• Isolation (shut-off valves) should be used to ease future servicing.
• All piping should be insulated.
1. Install a shut-off or check valve or both on the cold inlet connection
on the top or side of the heater. Connect the cold water supply line
to the shut-off valve or check valve. Refer to piping Applications, this
manual.
2. Connect the hot water line to the top or side hot outlet connection
on the top of the water heater. Then connect the hot water line.
3. Ensure the T&P Valve is installed in the ports provided on the side
or top of the water heater.
Water piping, fittings, and valves must be properly installed for
the correct and safe operation of this water heater. Please note the
following:
• DO NOT install this water heater with iron or PVC piping. The
system should be installed only with piping that is suitable
for potable (drinkable) water.
• DO NOT use any pumps, valves, or fittings that are not
compatible with potable water.
• DO NOT use valves that may cause excessive restrictions to
water flow. Use full flow ball or gate valves only.
• DO NOT use 50/50 tin-lead solder (or any lead based solder)
in potable water lines. ONLY use 95/5 Tin / antimony or other
equivalent materials.
• DO NOT tamper with thermostat heater elements, electrical
connections, or temperature and pressure relief valves.
Tampering with any of these components is DANGEROUS
and can result in property damage, severe injury, or death.
Tampering voids all warranties. Only qualified technicians
should service the above components.
• DO NOT use with piping that has been treated with
chromates, boiler seal, or other chemicals.
• DO NOT add any chemicals to the system piping which will
contaminate the potable water supply.
• DO NOT install check valves on the cold water supply line to
the water heater.
B. Recirculation Lines
In some installations a return circulation line may be installed. The
recirculation line can be connected to the hot water inlet connection
using a tee.
