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Discuss Volt Free Relay in the Central Heating Forum area at PlumbersForums.net

Messages
10
Hi,
I need to connect 2 X 2 port valves to my boiler via a 10 way junction box.
My boiler needs a zero volt switch line so I think I need to install a relay, in series, between terminal 9, coming from the valves, to the boiler.
Any ideas what I need or when to get 1?
Cheers,

Keith.
 
Messages
964
1. I'm assuming you mean that in order to fire the boiler, you need a switch with no voltage on it to connect the two relevant boiler terminals.
2. Two way valves (normally) have five wires:
2a. Blue, which is neutral.
2b. Green / yellow which is earth.
2c. Brown, which is live to the motor valve.
2d. Grey, which is one side of a microswitch.
2e. Orange, which is the other side of the switch.
3. In a traditional voltage switching system:
3a. The programmer outputs 230V during an "on" cycle. This output is connected to the thermostat.
3b. If the thermostat sees heat is needed, It switches 230 v onto its output, which is connected to the motor brown wire.
3c. The motor's grey wire is connected to mains 230V, usually in the wiring centre. Because the microswitch in the valve is normally open, that 230V doesn't go anywhere.
3d. When the motor opens the valve, as it reaches the open position, it closes a microswitch and sends 230 V to the boiler from the grey wire via the orange wire.
3e. The boiler fires.
4. Because the grey and orange wires are either side of a switch, unless connected to anything else, they are a zero voltage item.
5. If you connect the grey and orange wires across your boiler terminals, they will constitute the required switch without the need for a relay.
6. I'd suggest testing it first. Providing you have the expertise and equipment:
6a. Make sure the earth is connected at all times.
6b. Power the motor brown and blue from the mains.
6c. Use a multi-meter to check for the absence of voltage across grey and orange.
6d. Do a continuity test across the grey and orange provided there is no voltage present on them.
 
Messages
10
1. I'm assuming you mean that in order to fire the boiler, you need a switch with no voltage on it to connect the two relevant boiler terminals.
2. Two way valves (normally) have five wires:
2a. Blue, which is neutral.
2b. Green / yellow which is earth.
2c. Brown, which is live to the motor valve.
2d. Grey, which is one side of a microswitch.
2e. Orange, which is the other side of the switch.
3. In a traditional voltage switching system:
3a. The programmer outputs 230V during an "on" cycle. This output is connected to the thermostat.
3b. If the thermostat sees heat is needed, It switches 230 v onto its output, which is connected to the motor brown wire.
3c. The motor's grey wire is connected to mains 230V, usually in the wiring centre. Because the microswitch in the valve is normally open, that 230V doesn't go anywhere.
3d. When the motor opens the valve, as it reaches the open position, it closes a microswitch and sends 230 V to the boiler from the grey wire via the orange wire.
3e. The boiler fires.
4. Because the grey and orange wires are either side of a switch, unless connected to anything else, they are a zero voltage item.
5. If you connect the grey and orange wires across your boiler terminals, they will constitute the required switch without the need for a relay.
6. I'd suggest testing it first. Providing you have the expertise and equipment:
6a. Make sure the earth is connected at all times.
6b. Power the motor brown and blue from the mains.
6c. Use a multi-meter to check for the absence of voltage across grey and orange.
6d. Do a continuity test across the grey and orange provided there is no voltage present on them.
Thanks,

I was looking at this type of set up.....
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But maybe this'd be better.

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