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13 Cards in this Set

  • Front
  • Back

Rule of thumb for superheat

A/C (high temp) 15


Cooler (med temp) 10


Freezer (low temp) 5

Reasons for to much oil in a system

Comp has been chanced and old oil was never removed


Oil added to system

Cure for too much oil

Drain oil and replace with correct amount check pipe sizing and p traps


Add oil separator if possible (check with manufacturer)

Low oil level causes

Low on charge


Improper instillation ( pipe size p-traps)


Short cycling

What will you see in a compressor with low oil

Worn rods and bearings


Crankcase shaft uniformly scores


Worn piston rings cylinder


Low oil in crankcase

What is flooding or flood back

As continuous stream of liquid refrigerant to compressor NOT full coulomb

What to look for in suction cooled compressor

Progressively scored shaft


Centre and rear bearings worn


Dragging rotor


Worn broken piston rods

What’s should you check if you suspect a compressor has slugging

Suction Pipe sagging near compressor where oil/ liquid can build up


TXV stuck open


Extreme overcharge

What can fix flooded starts

Crankcase heaters in above freezing temps


Pump down solenoid


What does pump down protect against


+pumpout

Pumpdown- flooded starts


Pumpout - short cycle

How can you roughly find out what temp of discharge port on a compressor


What is the hottest it should be

Measure discharge line 6” from comp and add 50-75


Below 300f discharge port


Below 225 6” from comp

Why might a comp over heat

High compression ratio


High suction gas temp


Lack of external cooling

What will affect the compression ratio more

Suction pressure