Lochinvar 502, 2072 operation manual Alarm contacts, Wiring of the cascade

5 Electrical connections

Alarm contacts

The SMART SYSTEM control closes another set of contacts whenever the heater is locked out or the power is turned off. This can be used to turn on an alarm, or signal a Building Management System that the pool heater is down.

Wiring of the cascade

When wiring the heaters for Cascade operation, select one heater as the Leader. The remaining heaters will be designated as Members. See page 48, Configuration of the Cascade for a detailed explanation of this procedure.

The return sensor of the Leader heater should be placed in the main system piping loop, upstream of the water being supplied to all the heaters (see FIG.’s 4-5, 4-6, and 4-7). The return sensors on the remaining Member heaters may also be placed in the same location as the Leader or they can be placed in each Member’s PVC piping loop in the Alternate sensor location, using the tapped sensor hole (FIG. 4-3). Should the Leader heater ever need to be replaced with one of the Member heaters in the Cascade, that Member’s sensor should be relocated to the previous lead heater’s supply sensor location for optimum operation of the cascaded units.

The supply/limit sensors of all cascaded heaters MUST be placed downstream, in the main system piping loop in the blended water, going out to the pool (FIG.’s 4-5, 4-6, and 4-7). The supply/limit sensor also serves as a high temperature limit for pool supply water and failure to locate all sensors in the blended water going out to the pool could result in higher temperature water than desired being discharged to the pool.

If an external thermostat or BMS is being used to enable or disable the cascaded heaters, the external thermostat or BMS should be connected to the Leader heater’s S1 input, located on the low voltage terminal board (see FIG. 5-5). Jumpers on all Member heaters should be left in place.

Communication between the Leader and the Member heaters is accomplished by using shielded, 2-wire twisted pair communication cable. Connect one of the twisted pair wires to terminal A on each of the low voltage connection boards, and the other wire of the twisted pair to terminal B on each of the low voltage connection boards. Connect the shield wire to the shield ground terminal on all of the heaters. If more than two heaters are on the Cascade, daisy chain the wiring from the Cascade terminals on the second heater to the Cascade terminals on the third heater, then from the third to the forth, and so on. The connections can be made in any order, regardless of the addresses of the heaters. Try to keep each cable as short as possible.

Installation & Operation Manual

Figure 5-5_Low Voltage Field Wiring Connections

TO MONITORING DEVICE			1	ALARM
			2	CONTACTS
TO MONITORING DEVICE			3	RUN-TIME
			4	CONTACTS
			5	OPEN	WAY-3	VALVE
THREE WAY			6	CLOSE
VALVE			7	COM
		REMOTE
			8	S1
	THERMOSTAT		9	S1
		/EMS
			10	S2
		N/A			STAGING
			11	S2
		N/A	12	S3
LOUVER			13	S3
PROVING		N/A	14	S4
SWITCH			15	S4
			16	LOUVER
			17	PROVING SW
LINE			18	LOUVER
TO LOUVER			19	RELAY COIL
	LOUVER RELAY		20	TANK
			21	AQUASTAT
	24VAC COIL			CN3
	FIELD PROVIDED
			22	TANK
FROM			23	SENSOR
	A		24	SHIELD	CASCADE
TO NEXT
PREVIOUS			25	A
HEATER	B
	A		26	B
HEATER	B		27	SHIELD
			28	+ 0-10V
			29	- BMS IN
			30	+ 0-10V
		OPTIONAL MODBUS	31	- RATE OUT
EXTERNAL			32	SHIELD
	A				MODBUS
AUTOMATIC
SEQUENCER/			33	A
BUILDING	SHIELD	OPTIONAL MODBUS	34	B
CONTROL	B		35	SHIELD
		SHIELD		CN2
	TO NEXT BOILER	A
		B
		BK	1			A
POOL SAFETY		G	2	20K	POOL	REV
						LBL20186
SUPPLY		R	3		SENSOR
					SUPPLY
10K/20K		W	4	10K
					POOL
	10K		5
POOL/BOILER				10K	RETURN
			6
					SENSOR
			7		NOT
			8		USED
				CN2

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