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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 |
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Reasons for to much oil in a system |
Comp has been chanced and old oil was never removed Oil added to system |
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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) |
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Low oil level causes |
Low on charge Improper instillation ( pipe size p-traps) Short cycling |
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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 |
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What is flooding or flood back |
As continuous stream of liquid refrigerant to compressor NOT full coulomb |
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What to look for in suction cooled compressor |
Progressively scored shaft Centre and rear bearings worn Dragging rotor Worn broken piston rods |
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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 |
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What can fix flooded starts |
Crankcase heaters in above freezing temps Pump down solenoid
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What does pump down protect against +pumpout |
Pumpdown- flooded starts Pumpout - short cycle |
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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 |
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Why might a comp over heat |
High compression ratio High suction gas temp Lack of external cooling |
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What will affect the compression ratio more |
Suction pressure |