Lochinvar 402 - 2072 Line voltage connections, EMS or remote thermostat connection

5 Electrical connections

Line voltage connections

1.Connect 120 VAC power wiring to the line voltage terminal strip in the junction box, as shown in FIG. 5-1.

2.Provide and install a fused disconnect or service switch (15 AMP recommended) as required by the code (see FIG. 5-1).

3.To activate a system pump, wire as shown in FIG. 5-1. If the motor is larger than 1 HP, you must install a contactor.

4.When connecting power to units which are to be cascaded, each unit must be connected to the same ground connection.

					BOILER ONLY
UNIT	UNIT PUMP			SYSTEM		DHW PUMP
SUPPLY		SUPPLY	PUMP SUPPLY				SUPPLY
L N G		L N G		L N G			L N G

Installation & Operation Manual

EMS or remote thermostat connection

An EMS, remote thermostat or other remote temperature control may be connected to the boiler (see FIG. 5-3). Follow the manufacturer’s instructions supplied with the remote temperature control for proper installation and adjustment. Connection of a set of dry switching contacts or a remote on/off thermostat to the low voltage connection board will allow the unit to be switched on and off by making or breaking a 24 VAC control circuit. Remove the factory jumper between the Staging S1 terminals on the low voltage connection board and connect the remote temperature control in its place, see FIG. 5-4 on page 46.

Ensure that all wiring used to connect the switching contacts of the remote temperature controller to the connection board are a minimum of 18 gauge and have

D

I

S

C O N N E C T

D

I

S

C

O

N

N

E

C

T

BOILER

PUMP

GROUND

SPLICE

D

I

S

C

O

N

N

E

C

T

SYSTEM

PUMP

120V RELAY

D

I

S

C

O

N

N

E

C

T

DHW

PUMP

120V RELAY

a maximum installed length of 300 feet (91.4m). Set the SMART SYSTEM control to a set point temperature slightly higher than the setting of the remote temperature control. This will ensure that the remote temperature controller functions as the operating control for the heater.

REMOTE

CHASSIS

GROUND

					REV A
L	N		R	R	LBL20175
	120V	UNIT	SYSTEM	DHW
		PUMP	PUMP	PUMP
SUPPLY
		1 HP MAX	RELAY COIL	RELAY COIL

Figure 5-1_Line Voltage Field Wiring Connections

Low voltage connections

1.Route all low voltage wires through the knockouts on the left side of the heater, as shown in FIG. 5-2.

2.Connect low voltage wiring to the low voltage connection board as shown in FIG. 5-4 on page 46 of this manual and the heater wiring diagram.

LOW

VOLTAGE

KNOCKOUTS

LINE

VOLTAGE

KNOCKOUTS

Figure 5-2_Routing Field Wiring

ON/OFF

CONNECTION

Figure 5-3_Remote ON/OFF Wire Connection

DHW (Domestic Hot Water) thermostat

Connect the DHW tank thermostat (FIG. 5-4) to the tank thermostat terminals on the connection board.

DHW tank sensor

If a tank sensor is used, it must be connected to the tank sensor terminals on the low voltage connection board. The correct Lochinvar sensor (TST20015) MUST BE USED.

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