Initial start-up of equipments. |
Central air handling unit | ||
Turn all circuit breakers to the "ON" position. Turn the selector switch to either the heat or cool | ||
position. The fan motor are started by depressing the appropriate start pushbutton. | ||
Cooling - | Refrigerant solenoid valve is controlled by remote thermostat | |
Upon a rise in temperature, the thermostat opens the solenoid valve. | ||
Upon a drop in temperature, the thermostat closes the solenoid valve, shutting off the | ||
refrigerant flow to the evaporator coil. | ||
Heating - | Upon a drop in temperature, the thermostat drives the SCR to supply the current to elec. heater. | |
Upon a rise above specified temperature, the thermostat drives the SCR to be closed | ||
and shuts off the current to elec. heater. | ||
Depressing the stop pushbutton shuts the units off. |
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 compressors sight glass. | |
3. | Open water supply valve to condenser and allow water to reach condenser. | |
4. | Open compressor suction and discharge shut-off valves. 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 | |
before determining cause of shutdown. | ||
6. | Check the high pressure safety switch by throttling condenser water allowing head pressure to | |
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 |
|
Comp start (cut in) |
Comp stop (cut out) |
||
High Press. switch |
Manual reset |
12.5 |
. |
Low Press. switch |
1.8 |
2.3 |
. |
Oil Press. switch |
Manual reset |
2.5 |
Time delay 60 sec. |
7 | Check low pressure safety switch by slowly closing suction shut-off valve. | |
A decrease of suction pressure will follow. Check compressor suction pressure gauge | ||
throughout this procedure throughout this procedure | ||
(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. | |
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. |