Carrier 50PSW036-360 Operating Limits See Table, Unit Start-Up, 50PSW Unit Operating Limits C

Table 5 — DIP Switch Block S2 —

Accessory 2 Relay Options

ACCESSORY 2	DIP SWITCH POSITION
RELAY OPTIONS	4	5	6
Digital NSB	Off	On	On
Water Valve — Slow Opening	On	Off	On
LEGEND

NSB — Night Setback

NOTE: All other DIP switch combinations are invalid.

START-UP

Use the procedure outlined below to initiate proper unit start-up.

NOTE: This equipment is designed for indoor installation only.

Operating Limits (See Table 6)

ENVIRONMENT — This equipment is designed for indoor installation ONLY. Extreme variations in temperature, humidi- ty and corrosive water or air will adversely affect the unit per- formance, reliability and service life.

POWER SUPPLY — A voltage variation of ± 10% of name- plate utilization voltage is acceptable.

NOTE: These operating conditions are not normal or continu- ous operating conditions. It is assumed that start-up is for the purpose of bringing the building space up to occupancy temperature.

WARNING

When the disconnect switch is closed, high voltage is pres- ent in some areas of the electrical panel. Exercise caution when working with the energized equipment.

Table 6 — 50PSW Unit Operating Limits (C)

BUILDING COMMISSIONING

50PSW		COOLING			HEATING
UNIT SIZE	Source	Load	Ambient	Source	Load	Ambient
	Min/Max	Min/Max	Min/Max	Min/Max	Min/Max	Min/Max
036	10/43	16/27	7/43	–1/27	16/49	4/29
060,120	10/49	16/32	7/43	–1/27	16/49	4/29
180,360	10/32	16/32	7/43	10/21	27/49	4/29

BUILDING OPERATING

50PSW		COOLING			HEATING
UNIT SIZE	Source	Load	Ambient	Source	Load	Ambient
	Min/Max	Min/Max	Min/Max	Min/Max	Min/Max	Min/Max
036	10/49	10/32	7/43	–7/27	16/54	4/29
060,120	10/49	10/32	7/43	–7/27	16/54	4/29
180,360	10/43	10/32	7/43	–7/21	16/49	4/29

Unit Start-Up

1.Turn off all power to unit.

2.Adjust all valves to full open position.

3.Restore power to unit.

4.Operate each unit in the cooling cycle. See Table 6 for unit entering water temperatures.

5.Operate each heat pump in the heating cycle immediately after checking cooling cycle operation.

NOTE: A time delay will prevent the compressor from re-starting for approximately 5 minutes. The time delay function can be overridden on the Complete C control board.

6.If unit fails to operate, perform the following system checks:

a.Check the voltage and current. Be sure they com- ply with electrical data on unit nameplate.

b.Check for loose terminal screws where wire con- nections have been made on both the line and low- voltage terminal boards.

c.Check the supply and return piping. Be sure they are properly connected to the inlet and outlet con- nections on the unit.

d.If the checks described above fail to reveal the problem and the unit still will not operate, contact a trained service technician to ensure proper diagnosis.

Scroll Compressor Rotation — It is important to be certain compressor is rotating in the proper direction. To determine whether or not compressor is 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.Turn off power to the unit. Install disconnect tag.

2.Reverse any two of the unit power leads.

3.Reapply power to the unit and verify pressures are cor- rect. The suction and discharge pressure levels should now move to their normal start-up levels.

CAUTION

When the compressor is rotating in the wrong direction, the unit makes an elevated level of noise and does not provide cooling. Damage to compressor will occur if allowed to operate in this manner.

After a few minutes of reverse operation, the scroll com- pressor internal overload protection will open, thus activating the unit lockout. This requires a manual reset. To reset, turn the thermostat on and then off.

NOTE: There is a 5-minute time delay before the compressor will start.

Flow Regulation — Flow regulation can be accom- plished by two methods. Most water control valves have a flow adjustment built into the valve. By measuring the pressure drop through the unit heat exchanger, the flow rate can be deter- mined. Adjust the water control valve until the flow of 0.09 to

0.13L/s is achieved. Since the pressure constantly varies, two pressure gages may be needed in some applications. See Table 7 for heat exchanger pressure drops.

An alternative method is to install a flow control device. These devices are typically an orifice of plastic material de- signed to allow a specified flow rate that are mounted on the outlet of the water control valve. Occasionally these valves produce a velocity noise that can be reduced by applying some back pressure. To accomplish this, slightly close the leaving isolation valve of the water regulating device.

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