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3 – START-UP INSTRUCTIONS
Use the following instructions and start-up checklist provided on the last page to check out the unit PRIOR to unit
start-up.
3.1– Unit Preparation
Check that unit has been installed in accordance with these installation instructions and all applicable codes.
3.2 – Internal Wiring
Check all electrical connections in unit control boxes; tighten as required.
3.3 – Compressor Mounting
Compressors are internally spring mounted. Do not loosen or remove compressor hold down bolts.
3.4 – Refrigerant Service Ports
Each refrigerant system has a total of 3 Schrader type Service gage ports. One port is located on the suction line,
one on the compressor discharge line, and one on the liquid line. In addition Schrader-type valves are located
underneath the pressure switches. Be sure that caps on the ports are tight.
3.5 – Compressor Rotation
It is important to be certain the compressors are rotating in the proper direction. To determine whether or not
compressors are rotating in the proper direction:
1. Connect service gages to suction and discharge pressure fittings.
2. Energize the compressor.
3. The suction pressure should drop and the discharge pressure should rise, as is normal on any start-up.
If the suction pressure does not drop and the discharge pressure does not rise to normal levels:
1. Note that the evaporator fan is probably also rotating in the wrong direction.
2. Turn off power to the unit.
3. Reverse any two of the compressor lead wires.
4. Turn on power to the compressor.
5. Check also phase monitor all ok green led before proceeding.
The suction and discharge pressure levels should now move to their normal start-up levels.
When compressors are rotating in the wrong direction, the unit will have increased noise levels and will not provide heating and
cooling. After a few minutes of reverse operation, the scroll compressor internal overload protection will open, which will activate
the unit's lockout and requires a manual reset. Reset accomplished by turning the thermostat on and off.
3.6 - Evaporator Fan
Fan belt and variable pulleys are factory installed. Remove tape from the fan pulley. See Table 5 for Air Quantity
Limits. See Table 7 for Fan Performance data. Be sure that fans rotate in the proper direction. See Table 6 for Fan
RPM at various fan motor pulley settings. To alter fan performance, see Evaporator Fan Performance Adjustment
section.
Unit
50TJM-18
50TJM-24
50TJM-28
50TJM-34
NOTE
IMPORTANT
Cooling
Minimum
Maximum
4,000
7,000
5,000
7,500
5,000
8,500
7,000
10,000
Table 5 – Air Quantity Limits.
Page 15
Electric Heaters
Minimum
Maximum
4,800
7,000
6,000
7,500
7,000
8,500
7,000
10,000
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