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mA
OUTPUT
19
LIGHT ON
18
17
LIGHT OFF
16
15
LIGHT OFF
14
B SETPOINT
13
12
A SETPOINT
11
10
9
DEG. F 40
45
50
55
60
DEG. C 4
7
10
13
16
OUTDOOR AIR TEMPERATURE
NOTES:
1. Light ON: Outside-air damper will open to allow free cooling
below this temperature.
2. Light OFF: Outside-air damper will close to its minimum posi-
tion and compressor will be energized above this temperature.
Fig. 41 — EconoMi$er2 Outdoor-Air
Damper Operation
HEATING, UNITS WITH ECONOMI$ER2 — When the
thermostat calls for heating, terminal W1 is energized. To pre-
vent thermostat short-cycling, the unit is locked into the Heat-
ing mode for at least 1 minute when W1 is energized. The
induced-draft motor is energized and the burner ignition
sequence begins. The indoor (evaporator) fan motor (IFM) is
energized 45 seconds after a flame is ignited and the damper
moves to the minimum position. On units equipped for two
stages of heat, when additional heat is needed, W2 energized
and the high-fire solenoid on the main gas valve (MGV) is en-
ergized. When the thermostat is satisfied and W1 is deener-
gized, the IFM stops after a 45-second time-off delay. The
economizer damper then moves to the fully closed position.
When using continuous fan, the damper will remain in the min-
imum position.
SERVICE
When servicing unit, shut off all electrical power to unit
and install lockout tag to avoid shock hazard or injury from
rotating parts.
Cleaning —
Inspect unit interior at the beginning of heat-
ing and cooling season and as operating conditions require.
EVAPORATOR COIL
1. Turn unit power off and install lockout tag. Remove
evaporator coil access panel.
2. If economizer or two-position damper is installed, re-
move economizer by disconnecting Molex plug and re-
moving mounting screws. Refer to accessory economizer
installation instructions or Optional EconoMi$er2 section
on page 16 for more details.
3. Slide filters out of unit.
4. Clean coil using a commercial coil cleaner or dishwasher
detergent in a pressurized spray canister. Wash both sides
of coil and flush with clean water. For best results,
D SETPOINT
LIGHT ON
C SETPOINT
LIGHT ON
LIGHT OFF
LIGHT ON
LIGHT OFF
65
70
75
80
85
90
95
100
18
21
24
27
29
32
35
38
backflush toward return-air section to remove foreign
material. Flush condensate pan after completion.
5. Reinstall economizer and filters.
6. Reconnect wiring.
7. Replace access panels.
CONDENSER COIL — Inspect coil monthly. Clean con-
denser coil annually, and as required by location and outdoor
air conditions.
One-Row Coils (Size 004) — Wash coil with commercial
coil cleaner. It is not necessary to remove top panel.
2-Row Coils (Sizes 005-007)
Clean coil as follows:
1. Turn off unit power and install lockout tag.
2. Remove top panel screws on condenser end of unit.
3. Remove condenser coil corner post. See Fig. 42. To hold
top panel open, place coil corner post between top panel
and center post. See Fig. 43.
4. Remove screws securing coil to compressor plate and
compressor access panel.
5. Remove fastener holding coil sections together at return
end of condenser coil. Carefully separate the outer coil
section 3 to 4 in. from the inner coil section. See Fig. 44.
6. Use a water hose or other suitable equipment to flush
down between the 2 coil sections to remove dirt and
debris. Clean the outer surfaces with a stiff brush in the
normal manner.
Fig. 42 — Cleaning Condenser Coil
Fig. 43 — Propping Up Top Panel
45
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