Manual 2100-425B
Page
17 of 21
SERVICE HINTS
1. Caution homeowner 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 operating costs.
2. Check all power fuses or circuit breakers to be sure
they are the correct rating.
3. Periodic cleaning of the outdoor coil to permit full
and unrestricted airflow circulation is essential.
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 all 208/230 volt
models, when G circuit is de-energized the indoor
blower motor will continue to run for one minute. On a
call for heating, circuit R-W1 make at the thermostat
pulling in heat contact for the strip heat and blower
operation. On a call for second stage heat, R-W2 makes
bringing on second heat contactor, if so equipped.
COMPRESSOR CONTROL MODULE
The compressor control module is standard 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 or break timer 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
than 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.
