Ingersoll-Rand ReliaTel, Manual, Page: 158 / 176

158 RT-SVD03L-EN
• If active on a single circuit dual compressor unit,
compressor 1 and compressor 2 will de-energize
after the appropriate delays during active cooling
and active reheat.
• RTRM compressor 2 disable input will function as
follows:
• 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.
N No otte e:: 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 incremental. 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 ™ Commercial 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 ™ Commercial 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.
N No otte e:: This function will also be active during
service test.
HPC Logic
High pressure cutout (HPC) is similar to the LPC in that
the unit may be given up to four tries to operate. Like
the LPC, the HPC provides reliability protection for
compressors, but it is also used for safety protection
due to the high operating pressures that the unit may
see.
N No otte e:: At no time should the HPC be removed or
disabled in order to maintain unit operation.
HPC Sequence of Operation
On a call for cooling, if the HPC switch is closed, the
compressor will be allowed to start. If at any time the
HPC opens, the unit will shut down immediately. After
a 15 minute period, if there is still a call for cooling, the
control logic will check to see if the switch has closed. If
not, the unit is locked out and requires a manual reset
to restart the unit.
If after 15 minutes the HPC is closed, and there is still a
call for cooling, the unit will be allowed to restart. Once
again, if the HPC opens, the unit will shut down and
wait fifteen minutes to validate a restart. If the switch is
closed, the unit will be allowed to restart.
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