Ingersol Rand Precedent TSC120F Series, Сервисные данные

Страница: 13 / 24

Sequence of Operation
RT-SVF28F-EN 13
ReliaTel Control Evaporator Fan Operation
(for Cooling Only Units)
When the fan selection switch is set to the “Auto” position,
the RTRM energizes the (K6) relay coil approximately 1
second after energizing the compressor contactor coil
(CC1) in the cooling mode. In the heating mode, the RTRM
energizes the (K6) relay coil approximately 1 second
before energizing the electric heat contactors. Closing the
(K6) contacts on the RTRM energizes the indoor fan relay
(F) coil to start the indoor fan motor (IDM). The RTRM de-
energizes the fan relay (F) approximately 60 seconds after
the cooling requirement has be satisfied to enhance unit
efficiency.
When the heating cycle is terminated, the indoor fan relay
(F) coil is de-energized at the same time as the heater
contactors.
When the fan selection switch is set to the “On” position,
the RTRM keeps the indoor fan relay coil (F) energized for
continuous fan motor operation.
When the unit is equipped with the optional clogged filter
switch, wired between terminals J7-3and J7-4 on the
ReliaTel Options Module (RTOM), the RTRM produces an
analog output if the clogged filter switch (CFS) closes for
two minutes after a request for fan operation.
When the system is connected to a remote panel, the
“SERVICE” LED will be turned on when this failure occurs.
Low Ambient Operation
During low ambient operation, outside air temperature
below 55°F, the RTRM will cycle the compressor and
outdoor fan motor “Off” for approximately 3 minutes after
every 10 minutes of accumulated compressor run time.
The indoor fan motor (IDM) will continue to operate during
this evaporator defrost cycle (EDC) and the compressor
and outdoor fan will return to normal operation once the
defrost cycle has terminated and the compressor “Off”
time delay has been satisfied.
Note: (For units with the dehumidification option) When
in dehumidification mode, the unit will not cycle as
described above.The unit will run continuously in
dehumidification mode at all ambient conditions
above 40
º F. Dehumidification is disabled at
ambient conditions below 40 º F.
ReliaTel Control Dehumidification
Single Compressor Units
On a call for dehumidification, the reheat valve is
energized and the compressor is turned on. When the
humidity control setpoint is satisfied, the valve is de-
energized and the compressor is turned off. If there is a call
for cooling or heating from the space temperature
controller, i.e. zone sensor or thermostat, while in reheat,
the reheat valve is de-energized and the compressor
continues to run, or the heat is turned on. The 3 minute
compressor on and off times are still active during
compressor operation.
Dual Compressor Units
The dehumidification cycle is only permitted above 40ºF as
indicated above and is not permitted during a heating
cycle or during a demand for 2
nd
stage cooling. Otherwise,
when an installed zone humidity sensor indicates a
relative humidity equal to or greater than the RH set point
as adjusted on the ReliaTel Options Module (RTOM), a
dehumidification cycle is initiated. The Sequence of
Operation for the dehumidification cycle is identical to that
of the second stage ReliaTel cooling cycle, except that the
hot gas reheat valve (RHV) is energized, allowing air from
the evaporator to be reheated. Also, any installed fresh air
damper is driven to minimum position.The
dehumidification cycle is terminated by initiation of a
heating cycle or a 2
nd
stage cooling cycle or when zone
humidity is reduced to 5% below the R.H. set point. In the
absence of a zone humidity sensor input, an on/off input
from a zone humidistat is used to initiate/terminate the
dehumidification cycle.
Dehumidification takes priority over a call for one-stage
cooling.
Heating or two-stage cooling takes priority over
dehumidification, and a relative humidity sensor takes
priority over a humidistat.
Dehumidification Coil Purge Cycle
On multiple circuit units with dehumidification/reheat
configured, a purge cycle will be active for compressor
reliability. The purpose of this function is to properly
distribute refrigerant and lubricant throughout the system
by temporarily switching to the unused section of the coil
for 3 minutes (purge cycle). The function operates as
follows:
1. A purge cycle will be initiated after 90 minutes of
accumulated compressor run time in only one mode:
cooling or dehumidification, without transitioning to
the other mode.
2. A purge cycle will consist of transitioning to the mode
that hasn’t run in 90 minutes of total compressor
operation.The cycle will last for a period of 3 minutes.
3. The 90-minute cycle count will be reset anytime there
is a normal transition between cooling and
dehumidification. Transitioning from one of these
modes to any other mode (off or heat) will not reset the
counter.
4. If the purge cycle is a cooling cycle, only the first circuit
will be activated. If it is a dehumidification cycle then
the normal 2-compressor dehumidification mode
cycle will be used.
5. The purge cycle will ignore the low ambient
dehumidification lockout feature.