19
S
TART
-U
P
P
ROCEDURE
AND
C
HECKLIST
Begin with power turned off at all disconnects.
1. Turn thermostat system switch to “Cool,” and fan switch
to “Auto” and turn temperature setting as high as it will
go.
2. Inspect all registers and set them to the normal open
position.
3. Turn on the electrical supply at the disconnect.
4. Turn the fan switch to the “ON” position. The blower
should operate after a 7 second delay.
5. Turn the fan switch to “Auto” position. The blower should
stop after a 65 second delay.
6. Slowly lower the cooling temperature until the unit starts.
The compressor, blower and fan should now be operating.
Allow the unit to run 10 minutes, make sure cool air is
being supplied by the unit.
On 2 stage models (models with a “V” in the 11th position)
the unit is now operating on low speed. After the 10
minute run, continue lowering cooling temperature until
blower speed increases indicating 2nd stage cooling. Make
sure cool air is still being supplied by unit and proceed to
step 7.
7. Turn the temperature setting to the highest position,
stopping the unit. The indoor blower will continue to run
for 65 seconds.
8. Turn the thermostat system switch to “OFF” and
disconnect all power when servicing the unit.
R
EFRIGERATION
S
EQUENCE
C
HECK
With the disconnect switch open, remove the field connected ther-
mostat wire from terminal R on TB1 terminal block. Place a jumper
across terminals R and G, and across R and Y on TB1 terminal block.
Close the disconnect switch. The following operational sequence
should be observed.
1. Current through primary winding of transformer TRANS1
energizes the 24-volt control circuit.
2. To simulate a mechanical call for cooling from the wall
thermostat, place a jumper across terminals R and Y of
terminal block TB1. The cooling is energized when the
room temperature is above the thermostat set-point for
cooling. The thermostat makes R to Y.
3.
UNIT WITH ECONOMIZER OPTION:
The compressor circuit
is interlocked through terminals 1 and 4 of the economizer
module. If the outdoor air enthalpy (temperature and
humidity) is not suitable for cooling, the economizer
terminals will be closed permitting compressor to be
energized.
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.
PSC Motor
Adjust the CFM for the unit by changing the speed tap of
the indoor blower motor at the EBTDR “com” connection
with one of the speed taps on “M1” or “M2”. (Black-High
Speed, Blue-Medium Speed, Red-Low Speed.)
EEM Motor
Adjust the CFM for the unit by changing the position of
the low voltage leads on the motor terminal block. White
is for fan only and gas heat, Yellow is for cooling. Refer to
Appendix A for blower performance at each speed tap.
NOTE:
If more than one lead is energized simultaneously,
the motor will run at the higher speed.
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. 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 the 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 the 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 Y and
between R and G on TB1 terminal block will simulate a
satisfied thermostat. The compressor 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.
