Catalogue

6 WSHP-PRC020D-EN
Features and Benefits
is no cross leakage between the water tube and the refrigerant gas (steel tube) coil.The ½” (009/
012/015/018) and ¾”(024/036) threaded water connections to the water-coil are available on the
exterior chassis top. A flexible hose connection with shut-off is typically used between the riser and
water-coil in/out connections on the chassis to reduce water vibration.
The refrigerant flow metering is made through a thermal expansion valve (TXV).TheTXV allows
the unit to operate with an entering fluid temperature from 25°F to 120°F, and an entering air
temperature from 40°F to 90°F.The valve precisely meters refrigerant flow through the circuitry to
achieve desired heating or cooling.
Unlike cap-tube assemblies, theTXV allows the exact amount of refrigerant required to meet the
coil load demands.This precise metering increases the over-all efficiency of the unit.
The unit’s reversing valve is piped to be energized in the cooling mode. All vertical high-rise units
ship in a heat pump configuration with a system reversing valve.
Supply/Return/Condensate Risers
Supply, return and condensate risers are available as a factory mounted and shipped option.The
risers are constructed from type L or M copper.The top of each riser is swaged to accept the same
size diameter riser from above.This helps facilitate installation of the water supply, return and
condensate to and from the unit. Insulation may be factory installed or field installed per order
selection.The insulation helps keep moisture from forming on the pipes and damaging building
construction.
The riser length may be ordered as standard in 96” to 120” lengths. See “Equipment Risers,” p. 9
for riser application information.
Unit Safety
All unit safety devices are provided to help prevent compressor damage. Low pressure switch and
high pressure switch are added to help protect the compressor operation under a low charge (40
psig) or during high discharge (650 psig) pressures. In cases where a low charge, or excessive loss
of charge occurs, each compressor comes equipped with an overload device to halt the compressor
operation.
A safety lockout provides the mechanical communication of the low and high pressure switches to
prevent compressor operation if the unit is under low or high refrigerant pressures, or during a
condensate overflow condition.The lockout relay may be reset at the thermostat, by cycling power
to the unit or through a LonTalk™ front end device (ZN510 control option).