BULLETIN FROM....

Spring 1993

"HEAT THEM BEFORE THEY COOL YOU"

A 20 h.p. air conditioning compressor could have 10 lbs. of freon in it after an extended shutdown ­ the small crankcase heater will need up to 48 hours to boil it out.

COOLING SYSTEMS

Make sure crankcase heaters are working and are turned on at least 24 hours and preferably 48 hours prior to start-up to boil out any accumulated refrigerant in the crankcase, thereby ensuring adequate lubrication on start-up and precluding damage from liquid slugging.

Prestart-up checks should include:

­ examining contactor points
­ checking cable connections tight
­ cleaning or replacing filters
­ cleaning evaporator and condenser finned coils
­ checking motors are protected by right size overload heaters
­ carrying out oil and freon analysis on larger units

Checks at start-up should include:

­ checking amperage draw
­ checking belts and greasing fan bearings
­ listening for any abnormal noises
­ checking compressor oil level ­ 1/3 to 2/3 of the glass
­ checking oil for flects of metal
­ checking moisture indicator/sight glass in the liquid line

We would also suggest these checks should be carried out midway through the air conditioning season.

We have had a number of losses on air conditioning equipment in schools. The costs and inconveniences can be reduced with regular maintenance.

HEATING SYSTEMS

As summer nears, thoughts should also include the servicing of boilers and heating system equipment.

With boilers being opened for cleaning and internal inspection, special attention should be given to the following items:

­ cleaning all connections to safety controls
­ cleaning chambers and bellows of float controls
­ checking float controls for worn or defective parts

Watertube boiler tubes should be individually flushed with a water lance to ensure they are clean and clear.

The bottom passages of cast iron boilers require special attention. Each section should be thoroughly flushed and checked for scale or sludge build-up.

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