Use the checklist provided below in conjunction with the “General Unit Requirement" checklist” to ensure that the unit is properly installed and ready for operation. Be sure to complete all of the procedures described in this section be- fore starting the unit for the first time.
[ ] Turn the field supplied disconnect switch, located up- stream of the rooftop unit, to the "Off" position.
WARNING
Hazardous Voltage!
Disconnect all electric power, including remote discon- nects before servicing. Follow proper lockout/tagout procedures to ensure the power can not be inadvert- ently energized. Failure to disconnect power before ser- vicing could result in death or serious injury.
[ ] Turn the 115 volt control circuit switch 1S1 to the "Off" position. It is located in the secondary of the 1T1 trans- former.
[ ] Turn the 24 volt control circuit switch 1S70 to the "Off" position. It is located in the secondary of the 1T2 & 1T3 transformers.
[ ] Turn the "System" selection switch (at the Remote Panel) to the "Off" position and the "Fan" selection switch (if Applicable) to the "Auto" or "Off" position.
[ ] Check all electrical connections for tightness and "point of termination" accuracy.
[ ] Verify that the condenser airflow will be unobstructed.
[ ] Check the compressor crankcase oil level. Oil should be visible in the compressor oil sight glass. The oil level should be 1/2 to 3/4 high in the sight glass with the com- pressor "Off".
[ ] Verify that the compressor discharge service valve and the liquid line service valve is back seated on each cir- cuit.
CAUTION
Compressor Damage!
Do not allow liquid refrigerant to enter the suction line. Excessive liquid accumulation in the liquid lines may result in compressor damage.
Compressor service valves must be fully opened before
Do not start the unit in the cooling mode if the ambient tem- perature is below the following minimum recommended op- erating temperatures:
Standard unit with or without HGBP - +55 F for 20 & 40 Ton
+50 F for 25 & 30 Ton
+45 F for 70 thru 130 Ton
+40 F for 55 Ton
+35 F for 50 Ton
+30 F for 60 Ton
Unit Start-Up (Continued)
Units with Low Ambient option without HGBP - 0 F
Units with Low Ambient option with HGBP - +10 F
Note: To prevent compressor damage due to no refrigerant flow, do not pump the system down with the compressor(s) below 7 PSIG under any circumstance.
[ ] Check the supply fan belts for proper tension and the fan bearings for sufficient lubrication. If the belts require adjustment, or if the bearings need lubricating, refer to the Service/Maintenance section of this manual for in- structions.
[ ] Inspect the interior of the unit for tools and debris. Install all panels in preparation for starting the unit.
Electrical Phasing
Unlike traditional reciprocating compressors, scroll com- pressors are phase sensitive. Proper phasing of the electri- cal supply to the unit is critical for proper operation and reli- ability.
The compressor motor is internally connected for clockwise rotation with the incoming power supply phased as
A, B, C.
Proper electrical supply phasing can be quickly determined and corrected before starting the unit by using an instru- ment such as an Associated Research Model 45 Phase Se- quence Indicator and following the steps below:
[ ] Turn the field supplied disconnect switch that provides power to terminal block 1TB1 or to the unit mounted dis- connect switch 1S14 to the "Off" position.
[ ] Connect the phase sequence indicator leads to the ter- minal block or unit mounted disconnect switch as fol- lows;
Phase Sequence | Unit Power |
Leads | Terminal |
Black (phase A) | L1 |
Red (phase B) | L2 |
Yellow (Phase C) | L3 |
[ ] Close the disconnect switch or circuit protector switch that provides the supply power to the unit's terminal block 1TB1 or the unit mounted disconnect switch 1S14.
WARNING
Hazardous Voltage!
Disconnect all electric power, including remote discon- nects before servicing. Follow proper lockout/tagout procedures to ensure the power can not be inadvert- ently energized. Failure to disconnect power before ser- vicing could result in death or serious injury.
HIGH VOLTAGE IS PRESENT AT TERMINAL BLOCK 1TB1 OR UNIT DISCONNECT SWITCH 1S14.
59