Carrier 30RAP010-060 Operating Limitations, Operation Sequence, Temperature Limits for

CAUTION

Never charge liquid into low-pressure side of system. Do not overcharge. Overcharging results in higher discharge pressure, possible compressor damage, and higher power consumption. During charging or removal of refrigerant, be sure water is continuously circulating through the cooler to prevent freezing.

Operating Limitations

TEMPERATURES (See Table 29 for 30RAP standard tem- perature limits).

CAUTION

Do not operate with cooler leaving chiller water (fluid) temperature (LCWT) below 40 F (4.4 C) for the standard units, or below 15 F (–9.4 C) for units factory built for medium temperature brine.

High Cooler Leaving Chilled Water (Fluid) Temperatures (LCWT) — During start-up with cooler LCWT above approx- imately 60 F (16 C), the unit expansion valve will limit suction pressure to approximately 90 psig (620 kPa) to avoid overload- ing the compressor.

Low Cooler LCWT — For standard units, the LCWT must be no lower than 40 F (4.4 C). If the unit is the factory-installed optional medium temperature brine unit, the cooler LCWT can go down to 15 F (–9.4 C).

Table 29 — Temperature Limits for

Standard 30RAP Units

UNIT SIZE 30RA	010-030		035-060
Temperature	F	C	F	C
Maximum Ambient	120	49	120	49
Temperature
Minimum Ambient	45	7	32	0
Temperature
Maximum Cooler EWT*	95	35	95	35
Maximum Cooler LWT	70	21	70	21
Minimum Cooler LWT†	40	4.4	40	4.4

LEGEND

EWT — Entering Fluid (Water) Temperature

LWT — Leaving Fluid (Water) Temperature

*For sustained operation, EWT should not exceed 85 F (29.4 C). †Unit requires modification below this temperature.

LOW-AMBIENT OPERATION — If operating temperatures below 45 F (7 C) on size 018-030 units, and 32 F (0° C) on size 035-060 units are expected, accessory Motormaster® V con- trol must be installed. Operating temperatures can go as low as –20 F (–29 C) on size 010 and 015 units, as standard. Installa- tion of wind baffles is also required. Refer to separate installa- tion instructions for operation using this accessory. Contact your Carrier representative for details.

CAUTION

Brine duty application (below 40 F [4.4 C] LCWT) for chiller normally requires factory modification. Contact your Carrier representative for applicable LCWT range for standard water-cooled chiller in a specific application.

VOLTAGE — ALL UNITS

Main Power Supply — Minimum and maximum acceptable supply voltages are listed in the Installation Instructions.

Unbalanced 3-Phase Supply Voltage — Never operate a motor where a phase imbalance between phases is greater than 2%. To determine percent voltage imbalance:

	max voltage deviation
% Voltage Imbalance = 100 x	from avg voltage
	average voltage

The maximum voltage deviation is the largest difference between a voltage measurement across 2 legs and the average across all 3 legs.

Example: Supply voltage is 240-3-60. AB = 243 v

BC = 236 v AC = 238 v

1. Determine average voltage:

Averagevoltage = 243 + 236 + 238 3

=7173

=239

2.Determine maximum deviation from average voltage:

(AB) 243 – 239 = 4 v (BC) 239 – 236 = 3 v (AC) 239 – 238 = 1 v Maximum deviation is 4 v.

3.Determine percent voltage imbalance:

% Voltage Imbalance = 100 x	4
	239
= 1.7%

This voltage imbalance is satisfactory as it is below the maximum allowable of 2%.

IMPORTANT: If the supply voltage phase imbalance is more than 2%, contact your local electric utility company immediately. Do not operate unit until imbalance condition is corrected.

Control Circuit Power — Power for the control circuit is supplied from the main incoming power through a factory- installed control power transformer (TRAN1) for all models. Field wiring connections are made to the LVT.

OPERATION SEQUENCE

During unit off cycle, the control monitors the outdoor air temperature. If the ambient temperature drops below 40 F (4.4 C), cooler and hydronic system heaters (if either are facto- ry installed) are energized. If power is maintained to the chiller and the EMERGENCY ON/OFF switch is left in the OFF po- sition, these heaters are also energized.

The unit is started by putting the ENABLE/OFF/REMOTE CONTACT switch in the ENABLE or REMOTE CONTACT position. When the unit receives a call for cooling (either from the internal control or CCN network command or remote con- tact closure), the unit stages up in capacity to maintain the leav- ing fluid set point. The first compressor starts 11/2 to 3 minutes after the call for cooling.

The lead circuit can be specifically designated on all models or selected based on compressor run hours and starts depend- ing on field configuration. The unit control will override this selection under certain starting conditions to properly maintain oil return to the compressors. In general, on dual compressor

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