volt free relays

[ashleyqueen]

Could someone explain to me how volt free relays work and how they would be connected in a underfloor heating panel?

Thanks

 

[sparkytim]

All it means is that the switching contacts are not connected to the supply operating the relay.

So you have one independant circuit switching On or Off another independant circuit.

So for your underfloor heating a timer/thermostat fed from one circuit COULD switch on and off the underfloor heating fed from another circuit.

This is often used for large loads where the switch contacts would not cope.

So a 6Amp circuit could be used to control a 60 Amp Load VIA the relay also often called a Contactor.

 

[ProDave]

Re under floor heating, you really need the manual for your particular system as the DETAILS from one to another vary enormously.

But the principle is normally the same.

There is a "manifold controller" which is a control box next to the UFH manifold.

Normally the boilers timeswitch determines the on and off times. When the timeswitch is on, the manifold controller is activated.

Then if ANY of the zones for that manifold are "calling for heat" (determined by their thermostat) then the manifold pump will start and one or more zone valves will open.

At this point the manifold controller will itself "call for heat" in other words it's asking the boiler for some hot water. That is very probably a volt free contact. Now that may directly start the boiler, or that may activate a zone valve which in turn will start the boiler.

 

[SPECIAL LOCATION]

Basic electrical principals I suspect...

Any contact that does not output a voltage UNLESS you provide a voltage to it, is volt-free...

As such it could be used to switch any voltage or current within the rated capacity of the electrical contacts..

It may be the same voltage as the coil energising voltage or it may not..

e.g. could be 230v switching 12v or vice versa..

Clearly if this is a concept you have never encountered it may be wise to get some expert help in connecting up the heating.

Guinness