Initial start-up of condensing unit. |
Before compressor can start, all safety control contacts must be closed, cooling water flow to the | |
condenser closes the cooling water pressure switch contact. High pressure, oil failure and high | |
pressure switch must be in close position. | |
1. |
Crank case heater should be energized a minimum of 24 hours before starting compressor. |
2. |
Check to see that proper oil level appears in compressor sight glass. |
3. |
Open water supply valve to condenser and allow water to reach condenser. |
4. |
Open compressor suction and discharge shut-off valves. |
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Be sure all valves in refrigerant line are opened. |
5. |
If compressor is shut-off by safety control, do not permit control to reset more than once |
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before determining cause of shutdown. |
6. |
Check the high pressure safety switch by throttling condenser water allowing head pressure to |
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gradually rise. Check compressor discharge pressure constantly through this procedure. |
Compressor should shut-off within 1kg/cm2 of values shown on table below. |
Instruments |
Control Press (kg/cm2) |
Remarks |
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Comp start (cut in) |
Comp stop (cut out) |
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High Press. Switch |
Manual reset |
19.0 |
` |
Low Press. Swich |
0.6 |
1.6 |
` |
Oil Press. switch |
Manual reset |
0.4 |
Time delay 60 sec. |
7. |
Check low pressure safety switch by slowly closing suction shut-off valve. |
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A decrease of suction pressure will follow. Check compressor suction pressure gauge |
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throughout this procedure |
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(compressor should shut-off within 0.3kg/cm2 of the value shown on the table above 6). |
8. |
The oil failure switch may be checked by removing contact arm forward. |
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Compressor should stop in approximately 45-60 seconds. |
After completing test, press start button on front of safety switch and restart compressor. | |
Allow 3 minutes before attempting to reset switch. |