Trane ReliaTel Diagnostic Manual page 140

High Pressure and Low Pressure Lockout Circuits
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• If Active on a Dual Circuit Unit, only Circuit 2 will de-energize during Active Cooling. Both
Circuits will de-energize after the appropriate delays during Active Reheat (Circuit 1 after its
minimum on timer expires).
• If Active on a Single Circuit Dual Compressor unit, only Compressor 2 will de-energize
during Active Cooling and Active Reheat. Reheat will not be disabled in the case of the
Compressor 2 Disable Input going OPEN on these units. This is to ensure that a customer
who chooses to utilize the demand limit (load shedding) capabilities of the Compressor 2
Disable Input will still have some Reheat functionality. The LPC Lockout Incremental counter
will not increment if this input goes active since it is not actually in the refrigeration system.
RTDM Low Pressure Cutout Input:
The RTDM Low Pressure Cutout Input will be ignored for the first 10 minutes of compressor run
time on the reheat circuit (or compressor 1 if on a Single Circuit, dual Compressor unit). Once
active (OPEN), the associated circuit/output will de-energize and not be allowed to re-energize
until the 3 minute off timer is expired and the input has cleared. If the Reheat LPC trips 4 times
in any mode after the circuit has been energized for 10 minutes, dehumidification will be
disabled (all compressors off) and the reheat circuit will be locked out.
Note: For dual circuit units, a lockout on the reheat circuit will not disable cooling for the
opposite circuit.
The reheat LPC input will function in addition to the normal LPC input(s) located on the RTRM.
For units with modulating reheat, the RTRM LPC for the reheat circuit will cause the unit to de-
energize the appropriate circuit(s) and the total LPC count will be incremented. For these units,
a total of 4 LPC events on the reheat circuit (any combination from the RTRM or the RTDM reheat
circuit LPC inputs) will cause the unit to lock out the appropriate circuit(s). For dual circuit units,
the RTRM LPC input for circuit 2 will function as on normal, non-reheat units. See below for unit
configuration specific details:
• For Voyager 3 Dual Circuit Units if the RTDM Low Pressure Cutout input goes active (OPEN)
after the Reheat Circuit has been active for 10 minutes, the Reheat Circuit (Compressor 2
Output) will de-energize along with Circuit 1 (after its minimum on time) during Active
Reheat. For dual circuit units, if the unit is in Active Cool mode, the non-reheat circuit will
remain energized if the Reheat LPC goes active. Once this input clears, the unit will allow
dehumidification and cooling as necessary to meet demands and the inactive circuit(s) will
be allowed to re-energize after the 3 minute minimum off timer expires if necessary.
• For Voyager 3 Single Circuit (Dual Compressor) Units if the RTDM Low Pressure Cutout input
goes active after 10 minutes of run time on Compressor 1, both compressors will de-energize
during Active Reheat or Active Cooling. Once this input clears, the unit will allow
dehumidification and cooling as necessary to meet demands and the inactive circuit(s) will
be allowed to re-energize after the 3 minute minimum off timer expires if necessary.
There is no requirement to differentiate between the RTRM LPC inputs and the RTDM LPC input
for BAS/Network systems. If the unit has either the RTRM LPC input go active for the Reheat
Circuit or the RTDM LPC input go active, the control should just report an LPC event for that
circuit, regardless of which input is reflecting the condition. Also, the counter for RTDM LPC
events will not be reset unless power is cycled to the unit controller independent of how much
time has passed since the last RTDM LPC event.
Note: This function will also be active during Service Test.
RT-SVD03G-EN