McQuay M4MC Specifications download pdf (Page 16)

Pipings

Do not use contaminated or damaged copper tubings. If pipings, evaporator or condenser is exposed or had

been opened for 15 seconds or more, vacuum and purge with eld supplied refrigerant. Generally, do not

remove plastic, rubber plugs or caps from ttings, tubings and coils until ready to connect suction or liquid

line into ttings.

For MCC 075/100D/DR, the piping connections are brazing type. If any brazing work is required, ensure

that nitrogen gas is passed through coil and joints while brazing work is being done. This will eliminate soot

formation on the inside walls of copper tubings.

Electrical Connection

As wiring regulations differ from each country, please drefer to your LOCAL ELECTRICAL CODES for eld

wiring regulations and ensure that they are complied with. Besides, take note of the following general pre-

cautions:

1. Ensure that the rated voltage of the unit correspond to the name plate before commencing wiring work.

2. Provide a power outlet to be used exclusively for each unit and a power supply disconnect and a circuit

breaker for over-current protection should be provided in the exclusive line.

3. The unit must be EARTHED to prevent possible hazards due to insulation failure.

4. All wiring must be rmly connected.

5. Electrical wiring must not touch the refrigerant piping, compressor and any moving parts of the fan motor.

Operational Check

After all wiring is completed and system is charged with refrigerant, make sure unit is operating properly.

Check that:

1. Condenser fans are running with warm air blowing off the condenser coil.

2. Evaporator fans are running and discharging cool air.

3. Suction line pressures and condensing pressures are in the range of 60 – 75 psig. and 260 – 300 psig.

respectively in cooling cycle or 45 – 60 psig. and 245 – 285 psig. respectively in heating cycle.

4. Microprocessor electronic thermostats as used in the remote controls incorporate a 3 minutes delay in

their circuit. Thus it requires about 3 minutes upon start-up before the outdoor unit is activated.

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McQuay M4MC Specifications Page 16