Removed mechanical thermostat, now CH wont turn off.

[Jimbom2k]

Hi,

We have been decorating our hallway and had an ugly old mechanical thermostat mounted on the wall. I removed it because we never use it to adjust the CH temperature and the white plastic had aged and was going yellow.

After doing this the CH wouldn't come on (durr!), so I removed the two wires going into Ls and Lr in the boiler (a Worcester Greenstar Junior 24i) and put a link across them. Now the CH wont turn off. Have I linked the wrong terminals?

Thanks.

 

[Burnerman]

You seem to have effectively bypassed the thermostat, so now your system will run until closed down by the TRV's - if you have any.
Best to reinstate your stat!
John

 

[Jimbom2k]

Ive turned the boiler off for the moment so that I dont die in a pool of sweat.

I don't have the thermostat as it went in the bin, plus Ive removed the old wiring from the wall and filled in the hole. I really cant believe that the boiler wont operate without an external thermostat.

The installation manual does mention that there is a link inserted which you have to remove to fit an external thermostat. I was trying to reinstate this but it doesn't make clear which terminals you have to link.

 

[Burnerman]

I can't comment about linking the correct terminals, but it looks like you have found the correct pair.....!
With no stat, the boiler will merrily run all of the time, as there is now no external device to tell it that things are warm enough!
To avoid redecoration, consider a wireless stat.....a battery powered transmitter sits on the wall or furniture, and a receiver is directly wired into the boiler.
John

 

[Jimbom2k]

With no stat, the boiler will merrily run all of the time, as there is now no external device to tell it that things are warm enough!

There is a timer and temp setting knob on the fascia, would it not use these instead?

Thanks for the tip about the wireless stat, I'll look into this.

 

[Burnerman]

It will just make the boiler water run at a cooler temperature....not what you want!
A quality Honeywell stat is what you need.
John