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whl-648 Rev. 000 Rel. 003 Date 3.6.18
20
B. Backow Preventer
It may be recommended to use a backow preventer - check local
codes. If a backow preventer or a no return valve is used, a thermal
expansion tank must be installed on the cold water supply between
the appliance and the valve.
C. Expansion Tank
Expansion Tank
1. Ensure that the expansion tank is designed and sized to correctly
handle system water volume and temperature. Check technical
specications for the water content of this appliance.
Undersized expansion tanks cause system water to be lost from the
relief valve, causing make-up water to be added. Eventual appliance
failure can result due to excessive make-up water addition. SUCH
FAILURE IS NOT COVERED BY WARRANTY.
2. The expansion tank must be located as shown in Applications, this
manual, or following recognized design methods. See expansion tank
manufacturer’s instructions for details.
3. Connect the expansion tank to the air separator only if the air
separator is on the suction side of the circulator. Always install the
system ll connection at the same point as the expansion tank
connection to the system.
To control thermal expansion, a thermal expansion tank should be
installed in systems with an installed backow preventer. DO NOT use
a closed type expansion tank. Follow expansion tank manufacturer’s
specications to properly size an expansion tank to the installation.
Failure to properly accommodate thermal expansion could result in
property damage, severe personal injury, or death.
Expansion tanks must be sized according to total system volume.
This includes all length of pipe, all xtures, appliances, etc. Failure to
properly accommodate thermal expansion could result in property
damage, severe personal injury, or death.
DO NOT install automatic air vents on closed type expansion tank
systems. Air must remain in the system and return to the tank to
provide an air cushion. An automatic air vent would cause air to leave
the system, resulting in improper operation of the expansion tank.
Diaphragm (or Bladder) Expansion Tank
Always install an automatic air vent on top of the air separator to
remove residual air from the system.
D. Piping the Appliance
Use both thread tape and pipe dope to connect the 3/4” DHW inlet
and outlet pipes. A shut o valve between the city water supply and
DHW inlet is recommended for ease of service. Westinghouse oers
threaded 3/4” DHW tankless isolation valves with a DHW pressure
relief valve for ease of installation and future service.
Use both thread tape and pipe dope to connect the 1” CH return and
supply pipes. Isolation valves between are recommended for ease
of service.
Use at least the MINIMUM pipe size for all appliance loop piping
This is to avoid the possibility of inadequate ow through the
appliance. Using less than the required minimum pipe size and
piping could result in system problems, property damage, and
premature appliance failure. Such problems ARE NOT covered by
product warranty.
tPipe material must be suitable to meet local codes and industry
standards.
tThe pipe must be cleaned and without blemish before any
connections are made.
tThe size of the DHW pipes should be 3/4” diameter, and the CH
pipes should be 1” diameter.
tIsolation (shuto valves) should be used on both the CH and
DHW loops to ease future servicing.
tAll piping should be insulated.
It is recommended to install a sweat shut-o valve and a union in the
return and supply piping to ease future servicing. If there is a backow
preventer or any type of a no return valve in the system, install an
additional tee here, suitable for an expansion tank.