Sequence Of Operation - Lennox 10GCS Series Installation Instructions Manual

Use wiring with a temperature limitation of 75_C min.; run
the 208 or 230 volt, 60 hertz electric power supply through a
fused disconnect switch to control box of unit and connect
as shown in the wiring diagram located on the inside of the
control access panel.
Unit must be electrically grounded in accordance with local
codes or in the absence of local codes with the National
Electric Code, ANSI/NFPA No. 70 (latest edition) or CSA
C22.2 Part 1 (latest edition).
Power supply to the unit must be N.E.C. Class 1, and must
comply with all applicable codes. A fused disconnect
switch should be field provided for the unit. The switch must
be separate from all other circuits. If any of the wire
supplied with the unit must be replaced, replacement wire
must be of the type shown on the wiring diagram.
Electrical wiring must be sized to carry minimum circuit
ampacity marked
CONDUCTORS ONLY. Each unit must be wired with a
separate branch circuit and be properly fused.
When connecting electrical power and control wir
ing to the unit, waterproof type connectors MUST be
used so that water or moisture cannot be drawn into
the unit during normal operation.
See figure 9 for field connection of line voltage wiring. See
figure 7 for typical wiring diagram.
208/230 Line Voltage Wiring
contactor
ground
lug
NOTE − If 208 voltage is supplied, transformer
connections must be made.
Thermostat
The room thermostat should be located on an inside wall
where it will not be subject to drafts, sun exposure or heat
from electrical
manufacturer's instructions enclosed with thermostat for
general installation procedure. Color coded insulated wires
(# 18 AWG) should be used to connect thermostat to unit.
Four wires are required for cooling.
Heat Anticipator Setting
It is important that the anticipator setpoint be correct. Too
high of a setting will result in longer heat cycles and a
greater temperature swing in the conditioned space.
Reducing the value below the correct setpoint will give
shorter ON" cycles and may result in the lowering of the
temperature within
Anticipator Settings: 0.75 AMP
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on the unit. USE
CAUTION
fused disconnect switch
(furnished by installer)
Figure 9
fixtures or appliances.
the conditioned space.
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Sequence of Operation

Cooling System
The cooling section is a complete factory package utilizing
an air−cooled condenser. The system is factory−charged
with HCFC−22. The compressor is hermetically sealed,
internally sprung and base mounted with rubber−insolated
hold−down bolts.
Unit compressors have internal protection. In the event
there is an abnormal rise in temperature of the compressor,
the protector will open and cause the compressor to stop.
After the initial installation, the compressor should be
given three false starts (energized just long enough to
make a few revolutions), with 5−7 minutes between
each start, before being put into full time service.
Cooling Sequence of Operation
COPPER
When the thermostat calls for cooling, R" is closed to G"
and Y" (wiring schematic) which completes the low voltage
control circuit, energizing the compressor, condenser fan
motor and blower motor.
NOTE − At the start of the each cooling demand, the
combustion air blower (draft motor) will operate for 10
seconds.
Blower Delays − Cooling
Blower is controlled by a timing relay delaying blower on 5
seconds and blower off 90 seconds. This feature is
intended to deter insect nesting.
System Performance
For maximum performance of this cooling system, the
operating temperatures and pressure should be checked
and superheat determined at Standard ARI test conditions
of 82_ F outdoor temperature minus ( − ) 80_ F indoor dry
bulb / 67_ F indoor wet bulb. If superheat measured
deviates from values in table 4 below, refrigerant charge
L1
should be adjusted accordingly for maximum performance.
L2
Unit Model No.
10GCS−024
10GCS−030, −036
10GCS−042
Follow 10GCS−048, −060
12GCS−024, −030
12GCS−036, −042
12GCS−048, −060
NOTE − With the proper thermostat and subbase, continu
ous blower operation is possible by closing the R to G cir
cuit. Cooling blower delay is also functional in this mode.
Verify system performance using table 5 as a general guide.
Table should not be used for charging unit. Minor variations
in these pressures may be expected due to differences in
installations. Significant differences could mean that the
Heat system is not properly charged or that a problem exists with
some component in the system.
Page 11
Table 4
Suction Superheat Values
Suction Superheat
82_F OD minus 80_F IDDB
/ 67_F IDWB
18 − 20_
17 − 19_
18 − 20_
16 − 18_
18 − 20_
13 − 15_
14 − 16_