PSC Motor

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.

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.

WARNING

BURN HAZARD!

DO NOT TOUCH! DISCHARGE LINE MAY BE HOT!

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.

6.With all safety devices closed, the system will continue cooling operation until the thermostat is satisfied.

7.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.

8.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.

9.Open disconnect switch. Reconnect the field thermostat wire at terminal R on terminal block TB1.

REFRIGERATION PERFORMANCE CHECK

Under normal summertime (full load) operating conditions, superheat should be between 8°F and 12°F and sub-cooling measured at the condenser outlet should be 15°F (nominal). A 25°F to 35°F temperature difference should exist between the entering condenser air and the temperature correspond- ing to the compressor saturated discharge pressure. Check that compressor RLA corresponds to values shown in Ap- pendix C. RLA draw can be much lower than values listed at low load conditions and low ambient condensing tempera- tures. Values in Appendix C can slightly exceed at high load conditions and high ambient condensing temperatures.

GAS SUPPLY PRESSURES & REGULATOR ADJUSTMENTS

WARNING

SHOULD OVERHEATING OCCUR OR THE GAS SUPPLY FAIL TO SHUT OFF, TURN OFF THE MANUAL GAS SHUTOFF VALVE EXTERNAL TO THE UNIT BEFORE TURNING OFF THE ELECTRICAL SUPPLY.

WARNING

TO AVOID PROPERTY DAMAGE, PERSONAL INJURY OR DEATH, DO NOT FIRE GAS UNIT WITH FLUE BOX COVER REMOVED.

NOTE: Except during brief periods when gas pressures are being measured by qualified service personnel, the furnace access panel must always be secured in place when the furnace is in operation. An inspection port in the access panel is provided to monitor the flame.

The first step in checking out the gas-fired furnace is to test the gas supply piping to the unit for tightness and purge the system of air using methods outlined in the latest edition of the National Fuel Gas Code ANSI Z223.1. Verify that the disconnect switch is in the “OFF” position. A soapy water solution should be used to check for gas leaks. Since the unit is subject to considerable jarring during shipment, it is ex- tremely important that all gas connections and joints be tested for tightness. Gas piping downstream from the unit inlet should be checked for leaks during the subsequent sequence check.

The supply gas pressure should be adjusted to 7.0" w.c. on natural gas and 11.0" on LP gas with the gas burners operat- ing. If there is more than one unit on a common gas line, the pressures should be checked with all units under full fire. A