Thermostat not working?

[norecoil]

Hello,

I have a Salus RT100 thermostat connected to a Potterton Prima F30. As of yesterday, the thermostat no longer controls the boiler. It still 'clicks', but the boiler doesn't turn on. We still have hot water, and find that when the hot water is on and the boiler 'burns', we also get the heaters warming up normally. But as soon as we turn the hot water off on the controller, the boiler shuts down.

Any idea where the problem might be?

Compared to previously, the boiler will now heat up for some time before turning itself off shortly, and starting up again. Is there a risk of damaging the system? Or are we just wasting gas because the boiler can no longer tell when the required temperature has been reached?

Thanks!

EDIT: Now I'm not sure anymore. The hot water turned off (timer), the central heating program was still on, and the boiler kept going (unlike yesterday when the boiler would shut down if the hot water wasn't on). It just stopped, and started up again just as it would normally... *confused*

 

[picasso]

do you have two of these

honeywell 2 port

• picasso
• 18 Oct 2010
• 31

or one of these ?

honeywell 3 port

• picasso
• 18 Oct 2010
• 26

 

[norecoil]

The top one. Though it there is an inverted Y-shaped pipe on top (and one of the branches feeds into the pump).

 

[Dan Robinson]

huh?

 

[norecoil]

The top looks a bit like this:

[code:1]
| |
// \\
|P| ||
[/code:1]

Where P is the pump shown on top (one entry, one exit). The pipe on the right continues down. This is located in the cupboard where the hot water tank lives (there's a lot more tubing in there than I can handle with a text-based diagram ^_^).

 

[Dan Robinson]

How abotu a photo - 'cos that lot made no sense .

 

[norecoil]

Just got home, to pleasantly find the CH on. I'll try the thermostat later tonight... (too cold to do it now!)

Pictures as requested (which are really worth a 1000 ASCII diagrams):

Untitled

• norecoil
• 16 Jan 2012
• 1

Untitled

• norecoil
• 16 Jan 2012
• 1

Thanks!

 

[Dan Robinson]

OK, the pipe going up is the vent, possibly combined with the feed.

The problem maybe with the three port valve. That particular brand is not very good.