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Manual 2100-234I
Page 14 of 17
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. 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 WA121 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
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.