Coil or Water Source Heat Pump (WSHP) Piping Connections
Cooling and heating coil connections (water and steam)
are available in external or internal piping connections.
See submittals for type. External piping connections are
located on the supply side of the unit. Internal connections
are extended through the middle partition into the return
air compartment.
Split system cooling coil suction line connection is ex-
ternal, and liquid line is internal and located on the sup-
ply side of the unit. The liquid line does not include the
thermal expansion valve. With the coil access panel re-
moved, a field supplied and installed liquid line TXV can
be mounted inside the unit with an external equalizer line
connected to and a thermostatic sensing bulb strapped
to, the suction line. The TXV sensing bulb must be
strapped to the suction line at the 4 o’clock position. The
liquid line must be insulated and field extended outside of
the casing through the access panel and sealed.
WSHP water piping connections are external and factory
piped and extended to the end of the return air side of the
unit. See
for location.
Connections to the unit coil or WSHP system is by oth-
ers. External supply and return piping design and all other
safety, freeze protection or control piping requirements for
system operation are the sole responsibility of the Install-
ing Contractor and/or Design Engineer. Refer to ASHRAE
handbooks and local building codes for correct piping
procedures and proper installations. Refer to the submit-
tals for coil performance design information.
for WSHP water line piping requirements
and field mounted options and accessories.
A water flow switch is recommended to be installed in line
to prevent possible freeze-up due to loss of water flow.
An air vent must be installed on the high side of the water
line to discharge the non-condensable air in order to avoid
unexpected high head pressure and poor cooling/heating
performance. Manual shut-off valves are recommended to
be installed for the convenience of future service.
A circuit balancing valve with pressure and temperature
gauge connections is recommended to be installed in the
water line for balancing and service.
Before connecting piping to the unit, the water supply line
and return line must be flushed to eliminate the foreign
material.
CAUTION
On open loop systems, a field supplied and installed
water strainer (16–20 mesh minimum, 20–40 mesh best)
must be used in the water inlet or supply line to eliminate
contaminants for 14, 16 and 21 ton dual circuit WSHP
units which utilize a brazed plate heat exchanger con-
denser. Warranty will be voided without the presence of
the proper strainer.
CAUTION
For WSHP units, a water and glycol mixture is used for
factory installed water piping system tests and to prevent
any possibility of freezing during transit and/or storage.
Some glycol may remain in the system. Flush the system
in the field, prior to connection to the main supply and
return lines, if no glycol traces are desired.
In low temperature applications, the water supply line
and return line must be insulated to prevent condensate
and an antifreeze solution must be used to protect wa-
ter-to-refrigerant heat exchanger from freezing damage.
The concentration of water/glycol solution depends on
the field application.
CAUTION
Internal coil connections (water or steam) may only be
field extended through the cabinet within designated
areas. Refer to the interior coil connections label on the
floor of the coil access compartment. A pipe chase or
access openings to extend piping must be field cut by
the Installing Contractor then sealed air- and water-tight
as the access compartment is under a negative pres-
sure. If insulation was removed to create floor access
openings, insulation must be put back in place to avoid
condensation.
Do not
cut or drill holes through floor of
unit in non-designated areas without consulting the fac-
tory first. The structural integrity of the floor may be com-
promised and possible leaks may develop.
IMPORTANT
If the unit includes heating coil external connections and
split system direct expansion (DX) cooling coil connec-
tions on the supply side of the unit, the thermal expan-
sion valve (TXV) installation and refrigerant liquid line pipe
extensions must be completed with the coil access panel
removed before completing the heating coil and refriger-
ant piping connections.
VCES-VHC-IOM-1F – VHC-36, -42 & -50
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