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COMPRESSOR CONTROL MODULE
The compressor control module is standard on all
models covered by this manual. The compressor
control module is an anti-short cycle/lockout timer with
high and low pressure switch monitoring and alarm
relay output.
Adjustable Delay-on-Make And Delay-on-Break Timer
On initial power up or anytime 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 are closed, the
compressor contactor is energized. Upon shutdown,
the delay-on-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 re-energize 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 the 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 unit model. The lockout features,
both soft and manual, are a function of the
compressor control module.
ADJUSTMENTS
Adjustable Delay-on-Make and Delay-on-Break Timer
The potentiometer is used to select delay-on-break time
from 30 seconds to 5 minutes. Delay-on-make (DOM)
timing on power-up and after power interruptions is
equal to 2 minutes plus 10% of delay-on-break (DOB)
setting:
0.5 minute (30 seconds) DOB = 123 second DOM
1.0 minute (60 seconds) DOB = 126 second DOM
2.0 minute (120 seconds) DOB = 132 second DOM
3.0 minute (180 seconds) DOB = 138 second DOM
4.0 minute (240 seconds) DOB = 144 second DOM
5.0 minute (300 seconds) DOB = 150 second DOM
During routine operation of the unit with no power
interruptions, the compressor will operate on demand
with no delay.
Typical Settings for Dual Unit Installation:
Unit 1: DOB set at 2 minutes and DOM is 132
seconds
Unit 2: DOB set at 4 minutes and DOM is 144
seconds
PRESSURE SERVICE PORTS
High and low pressure service ports are installed on
all units so that the system operating pressures can be
observed. A pressure table can be found later in the
manual covering all models. It is imperative to match
the correct pressure table to the unit by model number.
See Table 2.
This unit employs high-flow Coremax valves instead of
the typical Shrader type valves.
WARNING! Do NOT use a Schrader valve core removal
tool with these valves. Use of such a tool could result
in eye injuries or refrigerant burns!
To change a Coremax valve without first removing the
refrigerant, a special tool is required which can be
obtained at www.fastestinc.com/en/SCCA07H. See the
replacement parts manual for replacement core part
numbers.
Manual 2100-581D
Page
17 of 26
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