Carrier 30RA/RH The controls, Evaporator pumps, Evaporator heater, Boiler, General description

3.5 - The controls

Evaporator pumps

The controller can regulate one or two evaporator pumps and takes care of automatic change-over between pumps.

Evaporator heater

It protects the evaporator (and the pipe heater for units without pump) against freezing if the unit is off.

Boiler

This relay output authorises start/stop of a boiler.

Condensate defrost heater

This heater is used for heat pump units and is located at the bottom of the air heat exchanger of each circuit. It prevents ice build-up, if defrost cycles are initiated at low outdoor temperatures.

3.6 - Connections at the user's terminal block

3.6.1 - General description

The contacts below are available at the user's terminal block on the NRCP-BASE board (see figure 1). Some of them can only be used if the unit operates in remote operating type (rEM).

The following table summarises the connections at the user’s terminal block.

SINGLE-CIRCUIT UNITS

Description	Connector/channel	Terminal	Board	Remarks	Remarks
Alarm relay output	J3 / CH24	30 - 31	NRCP-BASE	Indicates alarms	Volt-free contact 24 V a.c.
Boiler relay output	J3 / CH25	37 - 38	NRCP-BASE	Boiler start/stop control output.	48 V d.c. max, 20 V a.c. or
					V d.c., 3 A max, 80 mA min,
				See section 5.13.
					external power supply.
					Connector: 4 pin
					WAGO 734-104 pitch 3.5.
					One per board needed.
Contact 1:	J4 / CH8	32 - 33	NRCP-BASE	The contacts are used for unit start/stop and	24 V a.c., 20 mA
start/stop/heat/cool				heat/cool control. They are only taken into
				account if the unit is under remote operation	Connector: 8 pin WAGO
				control (rEM).
Contact 2:	J4 / CH9	63 - 64	NRCP-BASE		734-168, pitch 3.5
start/stop/heat/cool
				See the description of these contacts in
				sections 3.6.2 and 3.6.3.
Contact 3:	J4 / CH10	73 - 74	NRCP-BASE	Depending on the configuration, this dry
demand limit selection or				contact can be used for remote setpoint
setpoint selection				selection or demand limit selection (see
				sections 4.3.11.3 and 3.6.4).
				- The remote setpoint selection contact is
				only taken into account if the unit is in
				remote control operating type.
				- The remote demand limit selection contact
				is active whatever the operating type of the
				unit.
User safety loop input	J4 / CH11a	34 - 35	NRCP-BASE	This contact is mounted in series with the
				water flow control contact. It can be used for
				any customer safety loop that requires that
				the unit is stopped, if it is open.
				If it is unused this contact must be bridged.
Connection to CCN	J12	1 - 2 - 3	NRCP-BASE	An RS-485 bus is used for connection to the	Connector: 3 pin WAGO
				CCN.	231-303, pitch 5.08
				- Pin 1: signal +

- Pin 2: ground

- Pin 3: signal -

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