Daikin DCG Series Installation And Maintenance Manual Download

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4. The belt drive blower contactor closes its contacts L1, L2

and L3 to T1, T2 and T3 to provide power to the supply fan
motor.

5. Check supply fan rotation. If the supply fan is rotating in

the wrong direction, disconnect and lock off Single Point
Power Block. Do not attempt to change load side wiring.
Internal wiring is set at the factory to assure that the supply
fan and compressors all rotate in the proper direction.
Verification of correct supply fan rotation at initial startup
will also indicate correct compressor rotation. Reconnect
power and check for proper operation.

6. Compressor contactor closes its contacts L1, L2 and L3 to

T1, T2 and T3 to provide power to the compressor motor
COMP 1; COMP 2, if conditions are correct. In addition,
contactor C1 closes its contact L3 to T3 , energizing the
condenser fan motor.

BURN HAZARD!

DO NOT TOUCH! DISCHARGE LINE MAY BE HOT!

WARNING

7. Check that each compressor is operating correctly. The

scroll compressors in these units MUST operate in the
proper rotation. To ensure the compressors are operating
in the correct direction, check the compressor discharge
line pressure or temperature after each compressor is
started.
The discharge pressure and discharge line temperature
should increase. If this does not occur and the compressor
is producing an exceptional amount of noise, perform the
following checks.
• Ensure all compressors and the supply fan motor are

operating in the proper direction. If a single motor is
operating backwards, check the power wiring for that
motor and correct any leads that have been
interchanged at the contactor or at the motor.

• If all of the motors are operating backward, disconnect

the unit power supply and lock it in the “OFF” position.
Switch two leads of the power supply at the unit Single
Point Power Block. Reconnect power and check for
compressor and supply fan motor operation.

8. With all safety devices closed, the system will continue

cooling operation until the thermostat is satisfied.

9. Disconnecting the jumper wire between R and Y1 and Y2

and between R and G on TB1 terminal block will simulate
a satisfied thermostat. The compressors will cycle off and
IIC (pin 12) will initiate its time delay cycle. The compressor
and the supply fan will cycle off.

10. After a time delay of approximately 3 minutes, the

compressor control circuits will be ready to respond to a
subsequent call for cooling from the wall thermostat.

11. Open disconnect switch. Reconnect the field thermostat

wire at terminal R on terminal block TB1.

EFRIGERATION

ERFORMANCE

HECK

Under normal summertime (full load) operating conditions, super-
heat should be between 10 +/- 3° F and sub-cooling measured at
the condenser outlet should be 9 +/- 3°F (nominal). A 25°F to 35°F
temperature difference should exist between the entering con-
denser air and the temperature corresponding to the compressor
saturated discharge pressure. Check that compressor RLA corre-
sponds to values shown in Appendix B. RLA draw can be much
lower than values listed at low load conditions and low ambient
condensing temperatures. Values in Appendix B can slightly exceed
at high load conditions and high ambient condensing temperatures.

INAL

YSTEM

HECKS

1. Check to see if all supply and return air grilles are adjusted

and the air distribution system is balanced for the best
compromise between heating and cooling.

2. Check for air leaks in the ductwork. See Sections on Air

Flow Adjustments.

3. Make sure the unit is free of “rattles”, and the tubing in

the unit is free from excessive vibration. Also make sure
tubes or lines are not rubbing against each other or sheet
metal surfaces or edges. If so, correct the trouble.

4. Set the thermostat at the appropriate setting for cooling

and heating or automatic change over for normal use.

5. Be sure the Owner is instructed on the unit operation, filter,

servicing, correct thermostat operation, etc.

MAINTENANCE

HIGH VOLTAGE !

ISCONNECT

ALL

POWER

BEFORE

SERVICING

INSTALLING