Carrier 30XW150-400 specifications Pre-Start-Up, System Check, 30XW Compressor Nominal Capacity

Table 34 — 30XW Compressor Nominal Capacity

30XW UNIT SIZE	150	175	200	325	350	400
Compressor Nominal Capacity (tons)
Circuit A	182	182	204	182	182	204
Circuit B	—	—	—	182	182	204

Override #59: Circuit A Low Oil Level

Override #60: Circuit B Low Oil Level — This override is only effective when the circuit is not running. The override will prevent the circuit from starting up with a low oil level. If this override occurs three times, the low oil level alarm will be tripped.

Override #62: Circuit A High Motor Temperature Override

Override #63: Circuit B High Motor Temperature Override

—This override prevents the compressor motor temperature from rising above the high temperature limit, but still allows the chiller to run close to the high temperature limit by unload- ing the compressor. If the motor temperature is greater than 214 F (101.1 C), the compressor will not load. This override will remain active until the temperature drops below 214 F (101.1 C). If the motor temperature is greater than 225 F (107.2 C) for 60 seconds, the circuit capacity will decrease by one stage. If the motor temperature is greater than 228 F (108.9), the circuit capacity will decrease by one stage immediately.

Override #66: Circuit A High Discharge Gas Override

Override #67: Circuit B High Discharge Gas Override —

When the temperature is above the limit minus 2° F (1.1° C) in- crease in capacity will not be allowed. This override will re- main active until the discharge gas temperature drops below the limit by –3° F (–1.7° C).

Head Pressure Control — The Main Base Board (MBB) uses the saturated condensing temperature input from the discharge pressure transducer to control the head pressure control signal. Head pressure control is maintained through a calculated set point which is automatically adjusted based on actual saturated condensing and saturated suction temperatures so that the compressor(s) is (are) always operating within the manufacturer’s specified envelope. The control will automati- cally reduce the unit capacity as the saturated condensing tem- perature approaches an upper limit. See capacity overrides #16-18. The control will indicate through an operating mode that high ambient unloading is in effect. If the saturated con- densing temperature in a circuit exceeds the calculated maxi- mum, the circuit will be stopped. For these reasons, there are no head pressure control methods or set points to enter. The control will modulate the 0 to 10v head pressure control output signal when condensing temperature is below the minimum head pressure requirement for the compressor. See Table 34 for compressor nominal capacity.

LOW CONDENSER FLUID TEMPERATURE HEAD PRESSURE CONTROL OPTION — Units will start and op- erate down to 65 F (18.3 C) entering condenser water tempera- ture as standard. Operation with entering condenser water tem- peratures below 65 F (18.3 C) requires a field supplied and in- stalled condenser fluid control valve.

Sequence of Operation — Valve position is controlled through a 0 to 10 vdc signal provided by the MLV/COND board, channel 9, to maintain the head pressure set point. Unit sizes 325-400 use a common condenser so the MBB uses the highest saturated condensing temperature of either circuit. As a safety feature, if the circuit is on and if the saturated condens- ing temperature reaches the condensing set point +10° F, the valve is opened to its maximum position to avoid a high pres- sure alarm. The water valve is fully closed when the circuit is OFF on unit sizes 150-200 and if both circuits are off on unit sizes 325-400.

If the unit is configured as a heat machine, the valve will be maintained fully open when the unit operates in heating mode

and when the condenser leaving water temperature becomes greater than the head pressure set point.

Maximum and minimum condenser valve position is con- figurable. The minimum condenser valve position is very im- portant to avoid condenser freeze risks as condenser freeze pro- tection is ensured by the condenser pump.

To configure this option with the Touch Pilot™ display:

DISPLAY NAME			PATH		LINE NO.		VALUE
Condenser Water		Service→ FACTORY			13		YES
Val Sel
Water Val							Range: 80 to120 F
		Setpoint			38		(26.7 to 48.9 C)
Condensing Stp
							Default: 86 F (30 C)
Recl Valve Min		Service→ SERVICE1			19		Range: 0 to 50%
Position							Default: 20%
Recl Valve Max		Service→ SERVICE1			20		Range: 20 to 100%
Position							Default: 100%
Prop PID Gain		Service→ SERVICE1			6		Range: -20 to 20
Varifan							Default: 2.0
Int PID Gain		Service→ SERVICE1			7		Range: -5.0 to 5.0
Varifan							Default: 0.2
Deri PID Gain		Service→ SERVICE1			8		Range: -20 to 20
Varifan							Default: 0.4
To configure this option with the Navigator™ display:
ITEM	ITEM EXPANSION			PATH			VALUE
CON.V	Condenser Valve			Configuration→ UNIT		YES
	Select
W.SCT				Setpoint→ MISC		Range: 80 to140 F
	Water Val Cond Stp					(26.7 to 60 C)
						Default: 86 F (30 C)
HR.MI	Reclaim Water Valve			Configuration→ SERV		Range: 0 to 50%
	Min					Default: 20%
HR.MA	Reclaim Water Valve			Configuration→ SERV		Range: 20 to 100%
	Max					Default: 100%
HD.PG	Varifan Proportion			Configuration→ SERV		Range: –10 to 10
	Gain					Default: 2.0
HD.DG	Varifan Derivative			Configuration→ SERV		Range: –10 to 10
	Gain					Default: 0.4
HD.IG	Varifan Integral Gain			Configuration→ SERV		Range: –10 to 10
						Default: 0.2

NOTE: Operation of the head pressure control valve can be verified by entering Quick Test. From the Navigator display, go to Service Test\QUIC\FAN.A. From the Touch Pilot dis- play, go to MAIN MENU\Status\QCK_TST1\Q_VFANA.

PRE-START-UP

IMPORTANT: Complete the Start-Up Checklist for 30XW Liquid Chillers at the end of this publication.

The checklist assures proper start-up of a unit, and provides a record of unit condition, application requirements, system information, and operation at initial start-up.

Do not attempt to start the chiller until the following checks have been completed.

System Check

1.Check to ensure the unit is level per the installation instructions.

2.Electrical power source must agree with unit nameplate.

3.Check that auxiliary components, such as the chilled fluid and condenser fluid circulating pumps, air-handling equipment, or any other equipment to which the chiller supplies liquid are operational. Consult manufacturer's in- structions. If the unit has field-installed accessories, be sure all are properly installed and wired correctly. Refer to unit wiring diagrams.

4.Open compressor suction service valves (if equipped).

5.Open discharge, liquid line, oil line, and economizer (if equipped) service valves.

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