Standard Operating Conditions; Auto Random Re-Start Function - McQuay SB250B Installation Manual

Air cooled, ducted split type air-conditioners

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2. Charging procedures – Three phase compressors

The fundamental procedure is the same as for single phase models but the compressor can run in the wrong direction on

starting. If this happens reverse any two phases and start again. Short term reverse rotation will not damage the compressor.

All Specter compressors have internal discharge temperature protectors which are very effective in preventing dangerously

high discharge temperatures during charging. The protection module will trip and lock the compressors out for 30 minutes.

It is not normally necessary to wait 30 minutes for the module to reset. When the compressor has cooled down the module

can be reset by breaking the power supply to the control circuit. Very often the serviceman does not understand why the

module tripped and uses a jumper wire to bypass it. He continues to charge the system and removes the jumper when

charging is complete. The compressor may or may not run with the protector back in the circuit but it is certain that the

compressor has been damaged and premature failure is inevitable.

•

R407C must be charged as liquid. Usually R407C cylinder is equipped with a dip-pipe for liquid withdrawal.

If there is no dip-pipe, the cylinder should be inverted so as to withdraw liquid R407C from the valve.

•

Do not top-up when servicing leak, as this will reduce the unit performance. Vacuum the unit thoroughly and

then charge the unit with fresh R407C according to the amount recommended in the specification.

Cooling

Temperature

Minimum indoor

temperature

Maximum indoor

temperature

Minimum outdoor

temperature

Maximum outdoor

temperature

Ts: Dry bulb temperature.

Th: Wet bulb temperature.

•

Disconnect from the main power supply before servicing the air conditioner unit.

•

DO NOT pull out the power cord when the power is ON. This may cause serious electrical shocks which may

result in fire hazards.

If there is a power cut when the unit is operating, it will automatically resume the same operating mode when the power is

restored. (Applicable only to units with this feature)

Before turning off the power supply, set the remote controller's ON/OFF switch to the "OFF" position to prevent the

nuisance tripping of the unit.

If this is not done, the unit's fans will start turning automatically when power resumes, posing a hazard to service

personnel or the user.