Carrier 30MPA installation instructions Make Electrical Connections - All, a30-5047, a30-5048

SYSTEM

DILUTED

POT FEEDER AND TRANSFER PUMP

Step 7 — Make Electrical Connections — All

field wiring must comply with local code requirements. Electrical data for the complete unit and for the compressors is shown in Table 3. See Fig. 16 for field wiring connections. A

CLEANING

AGENT

			x
	TEMPORARY			30MPUNIT
	PUMP
			x
a30-5047
			TEMPORARY
		TO DRAIN	BYPASS

Fig. 14 — Typical Set Up for Cleaning Process

SYSTEM

field-supplied branch circuit disconnect switch that can be locked in either OPEN or OFF position must be installed.

Control circuit power is 24 v on all units. Factory-installed control transformer (TRAN 1) uses line voltage for all units. All control transformers are factory-installed and wired. For 208/230-3-60 units operating at 208-3-60 line voltage, TRAN1 primary connections must be moved to terminals H3 and H4.

Inside the control box are terminals for field power and ground (earth) wiring. A ground wire must be installed with each field power supply. Compressors are wired for across-the-line start. Refer to Table 3 for electrical data.

FLOW SWITCH — A condenser flow switch is available as an accessory for all 30MPW units, and can be field-installed. The Carrier flow switch accessory (part no. 30MP-900---004) is available for this purpose. Flow switch wiring terminals are

DILUTED

POT FEEDER AND TRANSFER PUMP

located in the field wiring compartment of the control box. The flow switch should be wired between terminals LVT-16 and

SIDE

STREAM FILTER

CLEANING

AGENT

	x
TEMPORARY	30MPUNIT
PUMP

x

LVT-17 for all units.

CONTROL BOX, POWER SECTION — The electrical power supply is brought in through the top left-hand side of the control box. Pressure-lug connections on the terminal blocks are suitable for only for copper conductors.

The control box power section contains the following

a30-5048		TEMPORARY
		BYPASS
	TO DRAIN

Fig. 15 — Cleaning Using a Side Stream Filter

Ensure the following when filling the system:

1.Remove temporary bypass piping and cleaning/flushing equipment.

2.Check to make sure all drain plugs are installed.

3.Open the blow-down valve to flush the strainer.

Normally, a closed system needs to be filled only once. The actual filling process is generally a fairly simple procedure. All air should be purged or vented from the system. Thorough venting at the high points and circulation at room temperature for several hours is recommended.

NOTE: Local codes concerning backflow devices and other protection of the city water system should be consulted and followed to prevent contamination of the public water supply. This is especially important when antifreeze is used in the system.

Set Water Flow Rate — Once the system is cleaned, pressur- ized, and filled, the flow rate through the chiller needs to be established.

NOTE: Carrier recommends a differential pressure gage when measuring pressures across the pumps or balancing valves. This provides for greater accuracy and reduces error build-up that often occurs when subtracting pressures made by different gages.

On primary/secondary systems, it is advisable to set the 30MP balancing valve to maintain design flow plus 10% through the chiller.

A rough estimate of water flow can also be obtained from measuring the pressure drop across the 30MP heat exchanger. Figures 11 and 12 show the relationship between gpm and heat exchanger pressure drop. It should be noted that these curves are for “clean” heat exchangers; they do not apply to heat ex- changers with fouling. Adjust the external balancing valve until the correct pressure drop is obtained for the required gpm.

components:

•power terminal block

•optional disconnect switch

•compressor circuit breaker(s)

•compressor contactor(s)

•current sensor boards

•control transformer

•ground lug

•neutral terminal (380-3-60 units only)

•crankcase heater relay (30MPA units only)

•fuses

CONTROL BOX, CONTROLS SECTION — The control box controls section contains the following components:

•main base board (MBB)

•scrolling marquee display

•optional energy management module

•control-circuit breakers for 24-v circuits

•control-circuit ON-OFF switch

•unit Enable/Off/Remote contact switch

•unit Alarm/Alert indicator light

CONTROL BOX, FIELD CONTROL WIRING SEC- TION — Inside this section is the low-voltage, field-wiring terminal strip (LVT). All low-voltage field-wiring connections are made to this terminal block. There are three 7/8-in. (22 mm) knockouts provided for field wiring in this section. Connec- tions for condenser flow switch, chilled fluid pump interlock, condenser pump interlock, remote alarm output, condenser output, and dual chiller thermistor accessory are made at these locations. See Fig. 16 for specific location of connections.

The unit has the capability to control field-supplied devices. They are: alarm signal, condenser pump or condenser fan out- put, and chilled water pump output. The unit provide 24-v power with a minimum 5 va rating per output allowed.

UNBALANCED 3-PHASE SUPPLY VOLTAGE — Never operate a compressor where a phase imbalance in the supply voltage is greater than 2%. Use the following formula to deter- mine the percent voltage imbalance:

% Voltage Imbalance =

100 x	max voltage deviation from average voltage
	average voltage

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