Operation, Piping, Installation, Wiring

OPERATION

The schematic drawing Fig. 2 is for a normally closed valve.

As shown, the valve is closed and the thermostat is satisfied. When the thermostat closes its contacts, the valve begins to open as a circuit is made from the transformer to the motor and thermostat, back to the transformer.

Shortly after the valve begins to open, the auxiliary switch closes (providing a low voltage auxiliary circuit for starting burner and/or circulator). After an elapsed time of about 10 seconds, the valve reaches the full open position. The valve motor now remains energized to keep the valve in the open position.

TYPE 'Z' ZONE VALVE

	BLACK
	N.O. CONTACT
	BLACK
AUX. SWITCH
	BROWN
	BLUE
MOTOR	GREEN

INTERNAL WIRING

EXTERNAL WIRING

2-WIRE HEATING

THERMOSTAT

HOT

LINE

TRANSFORMER

Fig. 2

When the thermostat is satisfied, the circuit through the valve motor is broken and a return spring begins to close the valve. Just before the valve reaches the closed position, the auxiliary switch opens to stop burner and/or circulator.

PIPING

A	B	A	B
VALVE CLOSED			VALVE OPEN

Fig. 3 Operation for normally close (N.C.) valve

The two most commonly used piping systems are shown below. Plan 1 is popular for new installations, while plan 2 is frequently used when converting two- pipe systems.

	PLAN 1	PLAN 2
Fig. 4	Water valves installed at the boiler	A common main supplies all
Fig. 4	header to provide a separate	zones, with a water valve installed
	supply to each zone.	on the riser to each zone.

Fig. 5

729

INSTALLATION

ALL GUARANTEES ARE VOID IF THE VALVE IS NOT ASSEMBLED ACCORDING TO THESE INSTRUCTIONS.

1.Disconnect electric power before connecting wiring to prevent electrical shock or equipment damage.

2.Select suitable valve location. Valve may be installed in any position, except upside down. The arrow on the side of the body indicates direction of flow throught the valve. (“A” is inlet, “B” is outlet)

3.Mount valve directly in the tube or pipe, as follows:

NOTE

For normally closed (N.C.) models, with sweat fittings, set the manual lever to the "MAN" position before applying heat to the fittings. This will protect the plug ball inside the valve by removing it from the seat. After installation, place manual lever in the "AUTO" position.

Flare fitting models

Use new, properly reamed pipe, free from chips. The valve body is threaded for standard 5/8 in. OD copper, 45° SAE flare-fitting nuts. These nuts are not furnished with the valve and must be obtained separately.

Sweat copper models

Use new, properly reamed pipe, free from dents or corrosion.

Sweat the joints, keeping the outer surface free from solder. DO NOT use silver solder because of the high melting temperatures required.

NPT pipe models

Use new pipe that is properly chamfered, reamed and free of burrs and chips. If using old pipe, be sure it is clean and free of rust, scale, burrs, chips and old pipe joint compound.

Apply pipe joint compound or teflon tape, only to the male threads of the pipe joint. DO NOT apply compound or teflon tape to the first two threads. If using a vise or open-end wrench to hold the valve while installing piping, do not tighten excessively, as this may damage the valve.

4. Support piping with a pipe hanger on each side of valve.

WIRING

All wiring should be done according to local and national electrical codes

Follow any specific wiring instructions provided by the boiler manufacturer. If none are supplied, the following diagrams offer typical wiring installations using 2-wire heating thermostats (.35A Heat-Anticipation) and other related controls.

A 40VA Transformer will handle up to 4 zone valves. A 20VA will handle up to 2 zone valves.