under floor heating VOLT FREE???

[Kev2632]

Hello, im struggling to get my head round this one, what is exactly mean by "volt free contacts", ive seen people saying that light switches are volt free? how can that be ?? when there is 240volts going through the switch if i was to measure between live and earth/neutral??

Could somebody explain it clearer please?

thanks

 

[telectrix]

a volt free relay has no voltage applied to the contacts untill you feed a voltage into it. so you can use it for 12V, 24V, 110V, 230V, etc. switching.

 

[Kev2632]

a volt free relay has no voltage applied to the contacts untill you feed a voltage into it. so you can use it for 12V, 24V, 110V, 230V, etc. switching.

Ok yea so you still feed the connection in the manifold with the 240volts yea? Why does it say that it's "volt free" then? :s

 

[oldtimer]

ok you get a light switch and by your physical action ie your finger you make and break the switch in the case of the relay your finger is replaced by a magnetic coil so that when you apply a voltage to it say via a timeclock it will make or break a switch that is not electrically connected to the timer circuit

 

[Kev2632]

ok you get a light switch and by your physical action ie your finger you make and break the switch in the case of the relay your finger is replaced by a magnetic coil so that when you apply a voltage to it say via a timeclock it will make or break a switch that is not electrically connected to the timer circuit

So basically you supply the the connection on the board where it says boiler relay and pump relay and that then in turn supply's the "volt free" relay is at right?

 

[Kev2632]

http://www.electric-heatingcompany....0/03/electric-boilers-tech-install-manual.pdf

Could somebody expalin why this " volt free contacts inside this electric boiler says volt free" but when the two cores leave from the zone valves will that not be 240 volts on those connections in the boiler??

 

[FrankUK]

Kev

Try to think of it this way.

Volt free means that the end doing the switching isn't adding any voltage to the circuit.

In the case of a boiler and a thermostat, the thermostat is a mechanical switch, operated by temperature. The thermostat is just a switch.
The boiler sends out 240v on one of the cable cores, and the thermostat relay sends this voltage back to the boiler, when the temperature says so (called a "call" in the trade).

As the thermostat is just switching the voltage from the boiler, it's relay contacts are called 'volt free'.

Hope this makes sense.

 

[Kev2632]

Kev

Try to think of it this way.

Volt free means that the end doing the switching isn't adding any voltage to the circuit.

In the case of a boiler and a thermostat, the thermostat is a mechanical switch, operated by temperature. The thermostat is just a switch.
The boiler sends out 240v on one of the cable cores, and the thermostat relay sends this voltage back to the boiler, when the temperature says so (called a "call" in the trade).

As the thermostat is just switching the voltage from the boiler, it's relay contacts are called 'volt free'.

Hope this makes sense.

Hello FrankUk, yea i sort of understand i was at a Electric heating company boiler today where there was a normal 2 zone valve heating with programmer and room stat etc etc, so for example yea, we switch on the heating at the programmer this sends a signal to the room stat then that in turn tells the valve to open yea? and that then causes one of the cores which are volt free too close and this will then fire the boiler up yea?? just think of it as a switch yea?

 

[telectrix]

basically a volt free relay is incorporated into , say, a boiler, alarm panel, or other electronic equipment. that equipment will energise the relay but the contacts have no voltage applied by the equipment. you apply the supply to the common contact/s to switch whatever you want the relay to switch.

 

[Kev2632]

basically a volt free relay is incorporated into , say, a boiler, alarm panel, or other electronic equipment. that equipment will energise the relay but the contacts have no voltage applied by the equipment. you apply the supply to the common contact/s to switch whatever you want the relay to switch.

Telectrix so basically those two "volt free " contacts ares the common contacts for a relay yea? and we supply it like you would wire a light switch yea??

 

[Kev2632]

is that right im thinking how it works Telectrix??

 

[Darkwood]

A volts free relay.....

When the voltage to opperate the coil that pulls in the contacts is totally isolated from the contacts

Example.... 24vdc coil has 24vdc applied to it and it pulls in its contacts now the contacts in a volts free relay are just a mechanical switch opening and closing as the coil energises and de-energises the relay contacts have no voltage present at them until you wire your external circuit through them to be controlled.

A relay that isnt volts free may have a connection from the coil A1 to the common on the relay thus will give out a voltage on the n/o or n/c terminals as the relay is operated.... a volts free relay allows you to bring in a voltage yourself through the contact i.e. ..... in a control circuit a 24v dc supply energises a relay that has 230v at one of the contacts common terminals which will either make or break the circuit you run through it.

 

[Marvo]

Kev, you've got 'volt-free' threads all over the board. I've just closed two of them, I'll leave this one open. If you have any further 'volt-free' type questions please keep them in this thread and don't open any new ones, it just causes confusion.

Cheers M.

 

[Stuuk1]

Talking about coils etc is just causing confusion if the OP doesn't understand what a volt free contact is..

Think of it this way and this is what I currently use them for.

A piece of equipment generates an alarm and operates a switch.

You as the user has to monitor that alarm.

You wire a pair to the switch to the common and either the normally open or normally closed terminals depending on the circuit design.

When the switch operates it makes or breaks your circuit (which you have supplied the voltage for).

No voltage is supplied from the equipment. This is essentially what a volt free contact is.