Install Instructions
IOM - HZH/HZV Series
45
White Thermistor Wire
White Thermistor Wire Red Three-Way Valve Wire
When flushing/purging units equipped with ClimaDry
II the unit should be fully flushed/purged before
attempting to flush/purge the ClimaDry
II coil. Once
the unit is flushed, energize the modulating three-
way dehumidification valve to allow flow through the
ClimaDry II hydronic circuit.
The unit must be powered (but not operating) during
flushing/purging. Unit power is required to operate the
three-way modulating valve during flushing.
Disable the ClimaDry
II
sensor located in the supply air
stream by removing the white wire from the low voltage
terminal block (LVTB) as shown in the figure that follows.
Energize the modulating three-way dehumidification
valve by removing the red wire from the ACC1 ‘N.O.’
terminal on the DXM2 board. Connect this wire to the
ACC1 ‘NC’ terminal of the DXM2 controller, as shown
in figure 1, to energize the modulating three-way
dehumidification valve. Once energized, the valve will
take 45 – 75 seconds to fully shift. Continue flushing
during this time. After the valve has completed its shift,
use the air bleed from the top of the reheat coil to purge
air from the coil.
De-energize the valve by removing the red wire from the
ACC1 ‘NC’ terminal on the DXM2 board. The valve will
spring return to its normal position in just a few seconds.
After the valve has fully returned, repeat the process of
running the valve through its cycle and purging air from
the reheat coil.
Under extreme circumstances this procedure may be
required multiple times to purge all air from the circuit.
After completing the flushing/purging procedure,
reconnect the red wire to the ACC1 ‘N.O.’ terminal on
the DXM2 for normal operation. Reconnect the white
sensor wire to the LVTB, as shown below. If air is allowed
to collect in the ClimaDry
II piping, nuisance trips may
occur. Additional flush/purge cycles may be used when
required.
Normal Unit Wiring
Red Three-Way Valve Wire
Flushing/Purging Units with ClimaDry II