Install Instructions

IOM - HZH/HZV Series
41
COAX
Note:
All components shown
are internal to the heat
pump unit.
(TO WATER LOOP)
(FROM WATER LOOP)
MODULATING
MIXING
VALVE
ENTERING
AIR
INTERNAL
PUMP
EVAPORATOR
COIL
LEAVING
AIR
REHEAT
COIL
REFRIGERANT OUT
(COOLING)
REFRIGERANT IN
(COOLING)
WATER IN
WATER OUT
The Loop Pump circulates condenser water through
the hydronic reheat coil during the reheat mode of
operation. In this application, the loop pump is only
energized during the reheat mode of operation. The
Hydronic Coil is utilized during the reheat mode of
operation to reheat the air to the setpoint of the
proportional controller. Condenser water is diverted by
the motorized valve and pumped through the hydronic
coil by the loop pump in proportion to the control
setpoint. The amount of reheating is dependent on
the setpoint and how far from setpoint the supply air
temperature is. The factory setpoint is 70–75°F [21-24°C],
generally considered “neutral” air.
ClimaDry II Application Considerations
Unlike most hot gas reheat options, the ClimaDry II
option will operate over a wide range of EWTs. Special
flow regulation (water regulating valve) is not required for
low EWT conditions. However, below 55°F [13°C], supply
air temperatures may not be maintained at 72°F [22°C]
because the cooling capacity exceeds the reheat coil
capacity at low water temperatures. Below 55°F [13°C],
essentially all water is diverted to the reheat coil (no heat
of rejection to the building loop). Although the ClimaDry
II option will work fine with low EWTs, overcooling of
the space may result with well water systems or on rare
occasions with ground loop (geothermal) systems (Note:
Extended range units are required for well water
and ground loop systems). Since dehumidification is
generally only required in cooling, most ground loop
systems will not experience overcooling of the supply
air temperature. If overcooling of the space is a concern
(e.g. computer room well water application), auxiliary
heating may be required to maintain space temperature
when the unit is operating in the dehumidification mode.
Unit minimum entering air temperature while in
the dehumidification or cooling, mode is 65ºF DB.
Operation below this minimum may result in nuisance
faults.
Water-Source Heat Pumps with ClimaDry II should not be
used as make-up air units. These applications should use
equipment specifically designed for makeup air.
ClimaDry II Schematic
ClimaDry II Modulating Reheat Option