Manual 2100-384B
Page
14 of 19
START UP
IMPORTANT INSTALLER NOTE
For improved start up performance, wash the indoor coil
with a dishwasher detergent.
SERVICE HINTS
1. Caution owner to maintain clean air filters at all
times and also not to needlessly close off supply
and return air registers. This reduces airflow
through the system, which shortens equipment
service life as well as increasing operation costs.
2. The unit is equipped with a high pressure cut out
switch.
3. Check all power fuses or circuit breakers to be sue
they are the correct rating.
4. Periodic cleaning of the outdoor coil to permit full
and unrestricted airflow circulation is essential.
HIGH PRESSURE SWITCH
The WE121 models are supplied with a remote reset
high pressure switch. If tripped, this pressure switch
may be reset by turning the thermostat off then back on
again.
SEQUENCE OF OPERATION
COOLING
– Circuit R-Y makes at thermostat pulling
in compressor contactor, starting the compressor and
outdoor motor. The G (indoor motor) circuit is
automatically completed on any call for cooling
operation or can be energized by manual fan switch on
subbase for constant air circulation. On a call for
heating, circuit R-W1 make at the thermostat pulling in
heat contact for the strip heat and blower operation.
COMPRESSOR CONTROL MODULE
The compressor control module is optional on the
models covered by this manual. The compressor
control is an anti-short cycle/lockout timer with high
and low pressure switch monitoring and alarm relay
output.
Adjustable Delay on Make and Break Timer
On initial power up or any time power is interrupted to
the unit the
delay on make
period begins, which will be
2 minutes plus 10% of the
delay on break
setting.
When the delay on make is complete and the high
pressure switch (and low pressure switch if employed) is
closed, the compressor contactor is energized. Upon
shutdown, the delay on break time starts and prevents
restart until the delay on break and delay on make
periods have expired.
During routine operation of the unit with no power
interruptions the compressor will operate on demand
with no delay.
High Pressure Switch and Lockout Sequence
If the high pressure switch opens, the compressor
contactor will de-energize immediately. The lockout
timer will go into a
soft lockout
and stay in soft lockout
until the high pressure switch closes
and
the delay on
break time has expired. If the high pressure switch
opens again in this same operating cycle the unit will go
into manual lockout condition and the alarm relay
circuit will energize. Recycling the wall thermostat
resets the manual lockout.
Low Pressure Switch, Bypass and Lockout
Sequence (Optional)
If the low pressure switch opens for more than 120
seconds, the compressor contactor will de-energize and
go into a soft lockout. Regardless the state of the low
pressure switch, the contactor will reenergize after the
delay on make time delay has expired. If the low
pressure switch remains open, or opens again for longer
that 120 seconds the unit will go into manual lockout
condition and the alarm relay circuit will energize.
Recycling the wall thermostat resets the manual lockout.
Alarm Relay Output
Alarm terminal is output connection for applications
where alarm relay is employed. This terminal is
powered whenever compressor is locked out due to HPC
or LPC sequences as described.
NOTE: Both high and low pressure switch controls are
inherently automatic reset devices. The high
pressure switch and low pressure switch cut out
and cut in settings are fixed by specific air
conditioner or heat pump unit model. The
lockout features, both soft and manual, are a
function of the Compressor Control Module.
