adding wired thermostat to Ferroli Modena 32HE problem

[floppy26]

Hi All.

AM trying to fit a new wired thermostat to the modena boiler (existing is a simple 24 hour manual timer). the instructions for fitting the stat (Salus RT500) mention just connecting a Neutral and Live (which serve as Live and SL). When wiring this, the fuse on the PCB is blowing.

The exisiting clock (manual 24hr one) has 4 wires connected (Live, Neutral and two others from the Terminal Blocks)

The Boiler book mentions removing the jumper from the terminal block but which this relates to. If connecting just the live and SL im left with the 2 other wires from the old clock doing nothing

Any help appreicated.

Leigh

 

[stem]

I don't have the wiring diagram for your Modena, but usually when there are 4 wires to a timeswitch there will be a Live and Neutral to power the timer and the remaining 2 wires will be the switch wires. The RT500 wired thermostat is powered by batteries, so does not need the Live and Neutral connections. In this case, only the 2 switch wires would be used at the new thermostat L (Live) and SL (Switched Live) The Live and Neutral would be disconnected or insulated and put safely out of the way.

If you are wiring the Live and a Neutral to the thermostat terminals, when it switches 'on' you are connecting them together which will blow the fuse, and it's possible to also damage the thermostat and / or boiler's circuit board.

If you could provide details of the original set up showing what wires go where at the boiler end and the original timer, someone will be able to confirm.

 

[muggles]

Fitting a Salus to a Ferroli? You do like quality gear, don't you

 

[floppy26]

Thanks for the reply Stem. Your comment about not needing the Live and Neutral (becasue of the batteries) made sense that i would then use the other two wires as the relays for the boiler... and job done - It also made sense that the jumper which it mentions needs removing would have been so i could use the thermostat to complete the ring instead of the jumper being there.

How confusing was that after a long day at work!

Thanks again for the reply it was MOST appreciated