Energy Tech Laboratories DSH Start-Upand Operation, Refrigerant Charges, Pressure Switch Settings

FORM 145.32-IOM1 (908)

START-UP AND OPERATION

Prior to starting unit for the first time, turn the thermostat system switch to OFF - or raise the cooling setpoint to the highest temperature, to prevent the unit from starting. Close the electrical disconnect switch. This will energize the compressor crankcase heater(s). WAIT A MINIMUM OF FOUR HOURS BEFORE STARTING THE SYSTEM. This period will allow the crankcase heater to vaporize any liquid refrigerant in the compressor crankcase.

Start unit and check rotation of fans and compressors.

Scroll compressors will only compress in one rotational direction. Three phase compressors will rotate in either direction depending upon phasing of the power. Since there is a 50-50 chance of connecting power in such a way as to cause rotation in the reverse direction, it is important to ensure proper rotation direction is achieved when the system is installed and operated.

Verification of proper direction is made by observing that suction pressure drops and discharge pressure rises when the compressor is energized. Reverse rota- tion also results in an elevated sound level as well as substantially reduced current draw.

If opposite rotation is needed, disconnect and reverse any two leads of the three phase supply. Reconnect power and observe for correct rotation.

Observe unit operation and check for unusual noise or vibration.

REFRIGERANT CHARGES

Ref. Charge	2 TON	3 TON	4 TON	5 TON
No. of Circuits	1	1	1	1
Per Circuit (lb)	7.625	8.125	11.188	10.938

The Air Conditioning section of this equipment is charged with R-410A; a hi- pressure refrigerant. Only qualified techni- cians, using appropriately pressure-rated test instruments, should perform trouble- shooting or service on this equipment.

PRESSURE SWITCH SETTINGS
	ALL MODELS
	High	Low
Cut Out (PSIG)	600	55
Cut In (PSIG)	450	75

There is no negative impacts on durability caused by operating three phase Scroll compressors in the re- versed direction for a short period of time (less than one hour). However, after several minutes of operation the compressors internal protector will trip.

RECCOMENEDED REFRIGERANT LINE SIZES

UNIT SIZE	LESS THAN 60 LINEAR FEET		60 - 150 LINEAR FEET
	LIQUID LINE	SUCTION LINE	LIQUID LINE	SUCTION LINE
2 TON	5/16	5/8	3/8	3/4
3 TON	3/8	3/4	3/8	7/8
4 TON	3/8	7/8	1/2	1-1/8
5 TON	3/8	1-1/8	1/2	1-1/8
8 TON	2 X 3/8	2 X 7/8	2 X 3/8	2 X 1-1/8
10 TON	2 X 3/8	2 X 1-1/8	2 X 1/2	2 X 1-1/8
12 TON	2 X 1/2	2 X 1-1/8	2 X 1/2	2 X 1-3/8
15 TON	2 X 1/2	2 X 1-1/8	2 X 5/8	2 X 1-3/8

NOTES: - Maximum Suction Lift 60 FT

-Maximum Liquid Line Rise 40 FT (measured from condensing unit level).

-Liquid Line Solenoid Valve required on systems over 100 linear feet.

-Suction Accumulator(s) required on systems over 125 linear feet.

Johnson Controls 15