I need to install one on my central heating system at the point where am connecting it to my new underfloor heating.
It will obviously be either open or closed, but my query is the cabl that they come wired to. Are they 2 or 3 core and how are they wire i.e do they use a common to switch them
-- Cordless Crazy
Cordless Crazy wrote:
I think you will need 4 core cable for this.
Neutral Live (Via the thermostat) Earth Open Signal (Connected to the boiler)
The open signal is connected to a small switch in the valve, so it only asks the pump and boiler to come on when the valve is known to be open.
The open signal wires need to all be connected together from all your valves, so when one or more is asking for the boiler, it fires up!
Sparks...
They usually have a cable attached - with up to 6 cores. Three of the cores are the live, neutral and earth to drive the motor and the other three are connected to a change-over switch (COM, NO, NC) which switches when the valve is open - and can be used to switch boilers, pumps etc, as appropriate.
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You're not fakefred, are you?
The Horstmann units are plastic encased and are Class II electrically so no earth required.
In addition to line and neutral to open the valve there will be a grey and orange which are connected to a switch to indicate the valve is open.
Sometimes there is a white wire which is the other contact is on the switch to show the valve is not open.
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