Boiler thermostat - replacing

Mutton_Geoff

fenwick458 said:

and would you care to explain why?

Programmable stats trigger the "call for heat" switched live, not the timed circuit.

fenwick458

they are the same thing!

southcoastrgi

fenwick458 said:

and would you care to explain why?

Ok the reason why is because the time clock fitted to the boiler is 240v switching, the op's cheap stat from Toolstation is volt free so if you try to fit it in place of the time clock or the room stat it will go bang, you need a programmable stat capable of 240v switching 

southcoastrgi

That's the problem with trying to fit modern controls to a old boiler 

fenwick458

southcoastrgi said:

fenwick458 said:

and would you care to explain why?

Ok the reason why is because the time clock fitted to the boiler is 240v switching, the op's cheap stat from Toolstation is volt free so if you try to fit it in place of the time clock or the room stat it will go bang, you need a programmable stat capable of 240v switching 

incorrect. volt free means you can add whatever you want to one side, and all it does is switch it to the other side at the times you set.

grumbler

southcoastrgi said:

fenwick458 said:

and would you care to explain why?

Ok the reason why is because the time clock fitted to the boiler is 240v switching, the op's cheap stat from Toolstation is volt free so if you try to fit it in place of the time clock or the room stat it will go bang, you need a programmable stat capable of 240v switching 

AFAIK, volt-free means just a switch (operated by a solenoid)  with both contacts not pre-wired  to anything. This switch is perfectly capable of switching 240V (up to 2A resistive load per the specifications) if wired accordingly.

southcoastrgi

fenwick458 said:

southcoastrgi said:

fenwick458 said:

and would you care to explain why?

Ok the reason why is because the time clock fitted to the boiler is 240v switching, the op's cheap stat from Toolstation is volt free so if you try to fit it in place of the time clock or the room stat it will go bang, you need a programmable stat capable of 240v switching 

incorrect. volt free means you can add whatever you want to one side, and all it does is switch it to the other side at the times you set.

grumbler said:

southcoastrgi said:

fenwick458 said:

and would you care to explain why?

Ok the reason why is because the time clock fitted to the boiler is 240v switching, the op's cheap stat from Toolstation is volt free so if you try to fit it in place of the time clock or the room stat it will go bang, you need a programmable stat capable of 240v switching 

AFAIK, volt-free means just a switch (operated by a solenoid)  with both contacts not pre-wired  to anything. This switch is perfectly capable of switching 240V (up to 2A resistive load per the specifications) if wired accordingly.

I have just checked the wiring for this stat & you are both correct, this stat can be set with 240v so my apologies for getting it wrong in this instance, however I would still wire it as I said 

thorganby

Mutton_Geoff said:

fenwick458 said:

and would you care to explain why?

Programmable stats trigger the "call for heat" switched live, not the timed circuit.

Anyone capable of reading and understanding the boiler documentation can see that your comment is irrelevant and incorrect.

The timeswitch is redundant, should be disconnected and the relevant link fitted when connecting the programmable stat.

Mutton_Geoff

thorganby said:

Mutton_Geoff said:

fenwick458 said:

and would you care to explain why?

Programmable stats trigger the "call for heat" switched live, not the timed circuit.

Anyone capable of reading and understanding the boiler documentation can see that your comment is irrelevant and incorrect.

The timeswitch is redundant, should be disconnected and the relevant link fitted when connecting the programmable stat.

I can read the manual and as an engineer, I prefer to do things properly. I'd still leave the time clock as is and set it to permanently on then wire a programmable stat into the room stat call for heat. The effect is the same but I prefer to do things logically so that if there was ever a fault, future engineers would start looking in the right place.

grumbler

AFAIK, not all mechanical room thermostats have 240V supply.