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The control then proceeds to “steady state” mode where all
inputs are monitored to ensure the limit switch, rollout
switch and prove switch are closed as well as flame is
present. When the heat call is satisfied and the gas valve is
de-energized, a combustion air inducer post purge period
of 5 seconds begins along with a 120 second blower off de
lay.
FIGURE 4
FLAME
CAI Line
Line voltage
LED
IGNITION CONTROL A3
B-Cooling Components
All units use independent cooling circuits consisting of sepa
rate compressor, condenser coil and evaporator coil. See
figure 5. One draw-through type condenser fan is used in
KGB024/090 units. Units are equipped with belt‐drive or di
rect drive blowers which draw air across the evaporator dur
ing unit operation.
Cooling may be supplemented by a factory‐ or field‐in
stalled economizer. The evaporator coil is slab type and
uses a thermostatic expansion valve or fixed orifice assem
bly as the primary refrigerant metering device. Each evapo
rator is also equipped with enhanced fins and rifled tubing. In all
units each compressor is protected by a freezestat (S49) on
the evaporator coil and a high pressure switch (S4) on the
discharge line. See figure 5. A Low ambient switch (S11) is
available as a field accessory for additional compressor pro
tection.
1-Compressor B1
IMPORTANT
The Clean Air Act of 1990 bans the intentional vent
ing of refrigerant (CFC's and HCFC's) as of July 1,
1992. Approved methods of recovery, recycling or re
claiming must be followed. Fines and/or incarcera
tion may be levied for non-compliance.
All KGB024/090 units use one scroll compressor. See
“SPECIFICATIONS” and “ELECTRICAL DATA” (table of
contents) or compressor nameplate for compressor specifi
cations. The KGB074 is equipped with a two-stage com
pressor.
WARNING
Electrical shock hazard. Compressor must be
grounded. Do not operate without protective cover
over terminals. Disconnect power before removing
protective cover. Discharge capacitors before servic
ing unit. Failure to follow these precautions could
cause electrical shock resulting in injury or death.
Each compressor is energized by a corresponding com
pressor contactor.
NOTE-Refer to the wiring diagram section for specific unit
operation.
If Interlink compressor replacement is necessary, call
1-800-453-6669.
IMPORTANT
Some scroll compressors have an internal vacuum
protector that will unload scrolls when suction
pressure goes below 20 psig. A hissing sound will
be heard when the compressor is running un
loaded. Protector will reset when low pressure in
system rises above 40 psig. DO NOT REPLACE
COMPRESSOR.
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