Glow Worm Ultracom 30cxi thermostat

[Superjohn]

I have a Glow Worm Ultracom 30cxi boiler and Sunvic TLM room thermostat. I am trying to make the central heating operate according to the boiler's internal timer but it only seems able to be controlled by the thermostat. I set the CH to come on at a certain time but it doesn't, the only way to get heating is to turn up the room thermostat which starts the boiler regardless of the scheduled state on the timer.

Is there an easy way to make the boiler ignore the thermostat via the settings or is it a matter of disconnecting the thermostat wiring altogether (and, from what I've read, installing a link wire across the BUS instead)?

I can live without the thermostat but would prefer not to have to unwire it completely if that is avoidable. I just want my heating to come on at set times instead of having to get out of bed to crank up the thermostat every morning!

Thanks in advance for any advice.

SJ

 

[Echo the husky]

You need to provide some wiring information showing what you have but my guess is the room stat has been wired into the frost stat terminal instead of the room stat terminal.

 

[Superjohn]

Would that be the connection at the installer interface box?

 

[Echo the husky]

Yes

 

[Superjohn]

Here is a picture of the connections in the installer interface. Live, neutral and earth are correct. There is a bridge between the R and F terminals and there is a black wire also connected to the R terminal. There is also a grey wire that isn't connected to anything. None of the terminals to the left of earth are connected to anything.

Can you make anything of that?

Thanks
SJ

 

[Echo the husky]

Yes someone has installed a link between room and frost terminals, disconnect the link leaving the black in the R terminal. I assume this boiler isn't somewhere cold like a garage or external boiler house and the installer hasn't tried to fake a frost stat?

 

[Superjohn]

Perfect! That got it working properly.

The boiler is in the kitchen area of a fifth floor, East London flat so frost isn't a major consideration. I can't think why it would have been wired that way in the first place. Maybe it was to suit a previous resident who was used to an older style system that was controlled by a thermostat, we will never know...

Thank you very much for your help, Echo. My mornings will now be toastie thanks to you!

SJ