Fuse ratings on boiler and room thermostat

[deadkenny]

Hi,

Just purchased an RF room thermostat kit to fit to my combi boiler, and not quite sure on the fusing involved.

The RF receiver connects to the 230V and 24V roomstat terminals on the boiler which I've identified in the boiler instructions, which is fine.

However the receiver specifies a 6A max fuse on the mains supply. Looking through the boiler installation instructions, the boiler apparently is supposed to use a 3A fuse on its mains supply (internally there's a 2A on the PCB also).

Would there be any problem if the receiver was covered by a 3A fuse instead of the 6A "max" it specifies?

I guess an alternative is to power the receiver off a separate fused mains socket / plug. I guess it doesn't have to connect to the boiler's 230V terminals. Although where do I get a 6A fuse anyway? Would a 5A do?

Just to complicate matters, I checked the mains fuse and discovered it's actually a 13A fuse in there! Surely this should be a 3A ?


p.s. if it's any use the boiler is an Industrie Fer Hawk II (yeah I know, you haven't heard of it. Few have! ).

 

[cider]

your electrical knowledge is worse then my spelling! max rating means the most the stat can handle in your case 2 amps. go carefull

 

[D_Hailsham]

The RF receiver connects to the 230V and 24V roomstat terminals on the boiler which I've identified in the boiler instructions,

You should have a Live and Neutral from the boiler to the receiver and a separate pair of wires from terminals 4 and 5 of the boiler to the switch terminals of the receiver? You should not have a link wire between L and either switch terminals on the receiver.

The only power used by the receiver is a few milliamps to run the electronics. There is nothing to worry about - the 3 amp fuse on the boiler will be fine.

I checked the mains fuse and discovered it's actually a 13A fuse in there! Surely this should be a 3A ?

If the boiler and associated controls are supplied from a fused spur or un-switched socket, the fuse should be 3 amp.

the boiler is an Industrie Fer Hawk II

Found the Manual on Ferroli's website!

 

[deadkenny]

your electrical knowledge is worse then my spelling! max rating means the most the stat can handle in your case 2 amps. go carefull

The 2A is the one on the PCB which I would have thought is just for the PCB. The 230V terminals for a roomstat connection appear to be the mains input connection and outside of the 2A protection. But I don't claim to be an expert by any means.

If it's 2A max then that may be fine anyway by the sounds of it...

The RF receiver connects to the 230V and 24V roomstat terminals on the boiler which I've identified in the boiler instructions,

You should have a Live and Neutral from the boiler to the receiver and a separate pair of wires from terminals 4 and 5 of the boiler to the switch terminals of the receiver? You should not have a link wire between L and either switch terminals on the receiver.

Yeah, that's exactly what I'd worked out, which is reassuring.

The only power used by the receiver is a few milliamps to run the electronics. There is nothing to worry about - the 3 amp fuse on the boiler will be fine.

If the boiler and associated controls are supplied from a fused spur or un-switched socket, the fuse should be 3 amp.

Cool. That makes it easy then it seems.

Found the Manual on Ferroli's website!

Yeah, that's where I got mine (so much for the installer leaving a copy). Already been useful in fitting the timer which the boiler didn't have installed either. Great thing is it listed the part and I found them easily (cheaper in fact on ebay!). So much for the likes of some certain service companies who claim "can't get the parts any more".

Thanks guys