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EL180XC, EL240XC
Thermostat Demand
(Key Number1)
STANDBY
COOLING 1
COOLING 2
COOLING 3
Footnotes:
1. Refer to Component Label or Wiring Diagram for key numbers.
2. 24V input signals measured between one TB14 connection listed and TB14-C connection.
HIGH PRESSURE SWITCHES (S4 AND S7)
These units are equipped with a manual reset high pres-
sure switch (single-pole, single-throw) which is located on
the discharge line. The switch shuts off the compressor
when discharge pressure rises above the factory setting.
High Pressure (auto reset) – trip at 640 psig; reset at 512
psig.
LOSS OF CHARGE SWITCHES (S24 AND S25)
NOTE – Used on units with two two-stage compressors.
These units are equipped with a loss-of-charge switch that
is located in the liquid line. The switch is a SPST, auto-re-
set switch that is normally closed. The switch opens at 40
psi and closes at 90 psi.
LOW PRESSURE SWITCH (S87)
NOTE – Used on units with one two-stage compressor.
These units are equipped with a loss-of-charge switch that
is located in the liquid line. The switch is a SPST, auto-re-
set switch that is normally closed. The switch opens at 40
psi and closes at 90 psi.
Maintenance
At the beginning of each cooling season, the system
should be checked as follows:
OUTDOOR UNIT
1 - Clean and inspect the condenser coil. You can flush
the coil with a water hose.
2 - The outdoor fan motor is prelubricated and sealed.
No further lubrication is necessary.
3 - Visually inspect connecting lines and coils for
evidence of oil leaks.
4 - Check wiring for loose connections.
Input Signals at
Compressor Output
Terminal Strip²
(TB14)
(B1)
R
OFF
C1
LOW
C1+C2
LOW
C1+C2+C3
HIGH
(B2)
(B4)
OFF
OFF
OFF
ON
LOW
ON
HIGH
ON
5 - Check for correct voltage at the unit while the unit is
operating and while it is off.
6 - Check amp-draw of the outdoor fan motor(s).
Unit nameplate _________ Actual ____________
7 - Check
amp-draw
Unit nameplate _________________________
Compressor #1 _________________________
Compressor #2 _________________________
NOTE – If the owner complains of insufficient cooling,
gauge the unit and check the refrigerant charge. Refer to
section on refrigerant charging in this instruction.
INDOOR UNIT
1 - If necessary, clean the coil.
2 - Check connecting lines and coils for evidence of oil
leaks.
3 - If necessary, check the condensate line and clean it.
4 - Clean or change filters.
5 - Adjust the blower speed for cooling. Measure the
pressure drop over the coil to determine the correct
blower CFM. Refer to the unit information service
manual for pressure drop tables and procedure.
6 - On belt drive blowers, check the belt for wear and
proper tension.
7 - Check all wiring for loose connections.
8 - Check for correct voltage at the unit (blower
operating).
9 - Check
Unit nameplate _________ Actual ____________
Page 22
Fans
(B5)
(B21)
OFF
OFF
ON
OFF
ON
ON
ON
ON
of
the
amp-draw
on
blower
(B22)
OFF
OFF
ON
ON
compressor(s).
motor.
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