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Flushing/Purging Units w/ Condenser Hot Water Reheat
When flushing/purging units equipped with Condenser
Hot Water Reheat the unit should be fully flushed/purged
before attempting to flush/purge the reheat coil. Once
the unit is flushed, energize the modulating three-way
dehumidification valve to allow flow through the reheat
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.
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 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.
Note: If the reheat sensor, located in the supply air
stream is above 70°F it must be disabled to allow
the modulating valve to shift. Disable this sensor
by removing the white wire from the Low Voltage
Terminal Block (LVTB) shown in figure 11.
Figure 11: Flushing/Purging Wiring
White Thermistor Wire
T H E S M A R T S O L U T I O N F O R E N E R G Y E F F I C I E N C Y
Red Three-Way Valve Wire
I n s t a l l a t i o n , O p e r a t i o n , M a i n t e n a n c e
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, if it was removed, as shown in figure 12.
If air is allowed to collect in the reheat piping, nuisance
trips may occur. Additional flush/purge cycles may be
used when required.
Figure 12: Normal Unit Wiring
White Thermistor Wire
JRE - Series
R e v . : A u g u s t 1 9 , 2 0 2 0
Red Three-Way Valve Wire
33
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