volt free contact inside electric heating boiler

[Kev2632]

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

Go down to page 8 of this document, you will see it asks for the contacts to fire the boiler up to be volt free, now i do finally understand i think what this means, it means that those two contacts R+P are independently volt free from the power being supplied to boiler, now what i cant understand with the way the booklet is telling you to wire the boiler up is, when wiring a normal 2x 2port valve set up, we supply either the orange or grey with 240 and the micro switch closes sending 240v down the other core, how can this boiler work when there will be no voltage at all applied to either orange or grey cores?? and is it possilbe to feed 240 volts onto one side of the R+P volt free contact at all ? and have 240 come out the side of either R+P ??

thanks again guys

 

[chilliwilly]

In this case R&P are in parrallel with the microswitches on on the actuators and just simply cause a short on the o/p and i/p of R&P and signal the boiler to switch on.

There will be more than likely be a 0v 4-20 ma signal source supplied from either R or P which will simply feed back into the boiler when switched. If you short the R & P out to test it with the boiler switched on, it should fire up. If not then check the voltage rating of R&P and check with manufacturers if voltage needs to be fed to them. Sometimes the term "volt free" is mis used by some manufacturers in different industries.

 

[Kev2632]

In this case R&P are in parrallel with the microswitches on on the actuators and just simply cause a short on the o/p and i/p of R&P and signal the boiler to switch on.

There will be more than likely be a 0v 4-20 ma signal source supplied from either R or P which will simply feed back into the boiler when switched. If you short the R & P out to test it with the boiler switched on, it should fire up.

okay yea i understand here, so is there anyway at all you can put 240v into one side of either R or P connection, like a light switch for example? or does this type of volt free connection not allow you to put 240v near it at all??

 

[Kev2632]

so i take it some case " volt free" can be used in such a way that you can feed 240v into one side of the connection and it then leaves the connection on the other side, or sometimes " volt free" can be just a case of using that connection as signal wire purpose is that right ???

 

[chilliwilly]

Without more spec from manufacturers, I wouldn't risk it. Test each o/p for voltage between and to earth and see what you get, then use a peice of wire for now and see if it works.

 

[Kev2632]

Without more spec from manufacturers, I wouldn't risk it. Test each o/p for voltage between and to earth and see what you get, then use a peice of wire for now and see if it works.

what do you mean by O/P ??

 

[paul_h]

Do not put 240v into r or p or your pcb is gonay have a bad time and it'll cost you a fair bit of money. I've wired boilers up by simply putting a two core flex into these connections and into a light switch. The light switch just breaks the loop stopping the boiler, once it's been switched on the loop is reinstated and boiler fires up.......


hope that makes sense.

 

[Kev2632]

Do not put 240v into r or p or your pcb is gonay have a bad time and it'll cost you a fair bit of money. I've wired boilers up by simply putting a two core flex into these connections and into a light switch. The light switch just breaks the loop stopping the boiler, once it's been switched on the loop is reinstated and boiler fires up.......


hope that makes sense.

Yea that makes sense thanks, so i take it there is different types of "volt free" connections is that correct?? just depends of manufactures instructions is that right??

 

[Kev2632]

Do not put 240v into r or p or your pcb is gonay have a bad time and it'll cost you a fair bit of money. I've wired boilers up by simply putting a two core flex into these connections and into a light switch. The light switch just breaks the loop stopping the boiler, once it's been switched on the loop is reinstated and boiler fires up.......


hope that makes sense.

http://www.myson.co.uk/static_files...V_Wiring_Centre_Installation_Instructions.pdf

like with this underfloor heating set up, it has volt free contacts on it, but i assume its possible to supply one side of this volt free contact with 240 volts is that right????

 

[Kev2632]

but i assume on this setup here,your not allowed too connect a neutral to those volt free connections is at correct??
http://www.myson.co.uk/static_files...V_Wiring_Centre_Installation_Instructions.pdf

 

[chilliwilly]

so i take it some case " volt free" can be used in such a way that you can feed 240v into one side of the connection and it then leaves the connection on the other side, or sometimes " volt free" can be just a case of using that connection as signal wire purpose is that right ???

Yes but in the event of uncertainty refer to manufacturer instructions, or just test the o/p and i/p between and to earth or short out the output o/p with the input i/p, and see if there's a function or change. That way you will know if whether or not a 4 - 20 ma signal is being used that needs feeding back in by switching or shorting, or whether a common feed is required to cause a function.

 

[Kev2632]

Yes but in the event of uncertainty refer to manufacturer instructions, or just test the o/p and i/p between and to earth or short out the output o/p with the input i/p, and see if there's a function or change. That way you will know if whether or not a 4 - 20 ma signal is being used that needs feeding back in by switching or shorting, or whether a common feed is required to cause a function.

thanks for your help, could you just have one last look at that other post i put on for the under floor heating, that also has "volt free" does that mean this set up will allow me to put 240v into one of the " volt free" contacts on the boiler and pump " volt free" connections ??? is that correct??

 

[snowhead]

now i do finally understand i think what this means, it means that those two contacts R+P are independently volt free from the power being supplied to boiler,

No, that's not what the manufacturer means when they say volt free.

VOLT FREE is free of any EXTERNAL voltage being applied to those appliance connections that also includes no external Neutral and No external earth connections.

The boiler control puts a voltage, nowadays usually low voltage onto the terminals and is looking for an external (volt free) closed contact to energise a circuit.

Re the other post DON'T put any voltage onto connections labelled Volt FREE.

 

[Kev2632]

No, that's not what the manufacturer means when they say volt free.

VOLT FREE is free of any EXTERNAL voltage being applied to those appliance connections that also includes no external Neutral and No external earth connections.

The boiler control puts a voltage, nowadays usually low voltage onto the terminals and is looking for an external (volt free) closed contact to energise a circuit.

Re the other post DON'T put any voltage onto connections labelled Volt FREE.

for the underfloor heating manifold, i was told that those volt free contacts you can supply 240 volts into one side of and take another out of it ( like a light switch) is that right???

 

[stuartcourt]

as above and you will find on the boiler that there is a 230 volt switch live

 

[Kev2632]

as above and you will find on the boiler that there is a 230 volt switch live

for the underfloor heating manifold, i was told that those volt free contacts you can supply 240 volts into one side of and take another out of it ( like a light switch) is that right???

 

[stuartcourt]

as said DO NOT put any voltage on to volt free contacts, you will need a volt free stat or the like to work it

 

[Kev2632]

as said DO NOT put any voltage on to volt free contacts, you will need a volt free stat or the like to work it

so why does the diagram physically show a "L" going into that "volt free connection then on that underfloor heating manifold??

 

[chilliwilly]

Yes that's right, the RHS top section shows the L & N being fed into the board, then the boiler and pump relays which are volt free, can be looped off to feed the Live side and switched internally.

In the case of the boiler, the manufacturer is calling R & P volt free, as some do? But there will more than likely be a neglegible voltage to drive a 4 - 20 ma current to switch or signal a component on the pcb.

As previously commented, check the voltage with a bench meter, or short out the i/p and o/p and see if you get a function?

 

[Kev2632]

Yes that's right, the RHS top section shows the L & N being fed into the board, then the boiler and pump relays which are volt free, can be looped off to feed the Live side and switched internally.

In the case of the boiler, the manufacturer is calling R & P volt free, as some do? But there will more than likely be a neglegible voltage to drive a 4 - 20 ma current to switch or signal a component on the pcb.

As previously commented, check the voltage with a bench meter, or short out the i/p and o/p and see if you get a function?

yea i thought i was right about the underfloor heating manifold, so if i was too loop of the live side to one side of the "volt free" connections, i assume then i will take a switch wire from the side of that switch to the boiler and pump is that correct???