Boiler staying on, frost stat continually kicks in

[djmorgan78]

Hi
I've got a Greenstar RI boiler, hot water cylinder in the airing cupboard, separate frost stat and pipe stat. The issue I'm having is that, i believe, the frost protection is very very frequently running the boiler, ( and central heating pump) throughout the day and night.
The frost stat is set below 5 deg, the pipe sat is set at the very minimum and yet the system kicks in frequently. Is this set correctly? The frost stat had a definitive click when turning it which makes me assume it works.
The pipe stat is set to the minimum but right now, despite the pipe being warm, as soon as i move it, even 1mm around, it starts the boiler. I've read that this should be set to about 20 deg, could this be faulty? I understand the Greenstar boiler also has built in frost protection?
The other issue, which I think is probably the root of everything, is that as you can see, the boiler is in a tiny garage room with wood doors and is very cold. I can probably do a little to insulate the room but with the wood doors I'm not sure how much good it will do.

Would anyone have any suggestions how to stop the boiler coming on frequently, the house rarely feels cold and the timer is only set for an hour in the morning, an hour early evening and 2 hours later in the evening. The water only comes on for 2 hrs in the evening. It's costing me about £2.50 a day in gas! Any help or suggestions regarding possibly faulty items, incorrectly wired in, incorrect set anything, or anything else would be much appreciated!

 

[picasso]

The frost stat is not connected to anything ? whats the story behind that ?

 

[ianmcd]

as @picasso says the frost stat is not connected to anything

 

[djmorgan78]

Lol, I was working on the assumption the wiring was in the wall. Might have a quick check and come back...

 

[flameport]

That taped up mess of a flex to the right of the unconnected thermostat also requires attention.

 

[djmorgan78]

Well just wow. I've lived here for about 6 years and within 2 mins of posting, 2 people have noticed that the thermostat i've been playing with for all that time, is connected to nothing....
Ok, so that's a problem, but i can get that sorted. So basically at the moment the pipe stat is simply turning the boiler on whenever the return pipe gets cold regardless if it's 30 deg outside? Again, wow.

One more thing, it does look as if it was connected at one point as the terminal screws are wound right out. The mess of flex that flameport noticed is joined just about at the right height to the wall stat. Any thoughts on why someone might have disconnect it?

 

[Mottie]

I've lived here for about 6 years and within 2 mins of posting, 2 people have noticed that the thermostat i've been playing with for all that time, is connected to nothing....

Lol. At least it’s kept you busy.

 

[djmorgan78]

Just thinking, if the boiler doesn't have a frost stat connected, i presume it's the boilers integrated protection turning the system on. So why does the pipe stat also fire the boiler when i turn it up from 0 deg to anything above 1 deg? Anyone, any ideas?

 

[flameport]

So why does the pipe stat also fire the boiler when i turn it up from 0 deg to anything above 1 deg

Wired incorrectly at the boiler
Wired incorrectly at the thermostat
Loose wires / connections
Defective thermostat
All of the above.

Given the state of it, and the easy access to all components, scrapping the existing wiring and replacing with new done properly would be the obvious solution.

Both thermostats wired in series, so both must be 'on' for the boiler to operate.
Wall frost thermostat set to about 5C so only operates with air temperatures below that.
Pipe thermostat on the boiler return and set to about 30C so it switches off once the pipe is above that temperature.

 

[djmorgan78]

Thank you for the response, and apologies for my inexcusable stupidity spanning 6 years.....

 

[jeff the gasman]

The frost stat is not connected to anything ? whats the story behind that ?

Is it one of those new fangled RF ones?

 

[djmorgan78]

Nope, just your standard, not connected to anything, run of the mill thermostat

 

[endaxi]

Hi djmorgan78,

I'm not a heating engineer, just a DIYer who has developed an unintentional interest in HW/CH.

I don't know about your system but I too have a Greenstar (24Ri) and I noted you mentioned your pump keeps running. My pump is in the airing cupboard and I had the same problem (amongst others). I now know from experience that many factors can influence what you may think is one fault and sometimes just some simple adjustments can either fix things or at least make any real faults easier to diagnose.

I see from your first picture that your boiler thermostat is set to the 12 o'clock position. When it is set fully clockwise it is set to 82c (if like mine). My water tank thermostat was set to 60c and I too had set my boiler stat for the summer to roughly where yours is, which is probably less than 60c.

This means that when there is a hot water demand, ie the water in the tank is less than 60c, then as long as the hot water is set to ON at the timer the pump will start. It will keep running until the hot water reaches 60c. If the boiler stat is set to under 60c (say 55c) then the demand will never be met as the boiler will switch off at 55c but the pump will keep running and pumping water through the tank coil until the hot water is switched off at the timer.

Try turning your boiler stat clockwise to at least the 3 o'clock position and see if that at least sorts the pump running problem. It may also have a bearing on your central heating demand, ie. can't satisfy it.

My instruction manuals require the tank stat to be at 60 and the boiler to be at 82.

Hope this helps in some way.

 

[breadnbutter]

looks like the cable that's been taped up was connected to that frost stat at some point, maybe a fault whith the frost stat, some ones disconnected it and wired it direct and taped it up.

 

[djmorgan78]

Hi djmorgan78,

I'm not a heating engineer, just a DIYer who has developed an unintentional interest in HW/CH.

I don't know about your system but I too have a Greenstar (24Ri) and I noted you mentioned your pump keeps running. My pump is in the airing cupboard and I had the same problem (amongst others). I now know from experience that many factors can influence what you may think is one fault and sometimes just some simple adjustments can either fix things or at least make any real faults easier to diagnose.

I see from your first picture that your boiler thermostat is set to the 12 o'clock position. When it is set fully clockwise it is set to 82c (if like mine). My water tank thermostat was set to 60c and I too had set my boiler stat for the summer to roughly where yours is, which is probably less than 60c.

This means that when there is a hot water demand, ie the water in the tank is less than 60c, then as long as the hot water is set to ON at the timer the pump will start. It will keep running until the hot water reaches 60c. If the boiler stat is set to under 60c (say 55c) then the demand will never be met as the boiler will switch off at 55c but the pump will keep running and pumping water through the tank coil until the hot water is switched off at the timer.

Try turning your boiler stat clockwise to at least the 9 o'clock position and see if that at least sorts the pump running problem. It may also have a bearing on your central heating demand, ie. can't satisfy it.

My instruction manuals require the tank stat to be at 60 and the boiler to be at 82.

Hope this helps in some way.

Endaxi, that makes a lot of sense. I did read about a guy who turned his water cylinder down but as I have such a tiny cylinder and such a huge bath that wasn't an option. I'm away for a bit this but will report back later, thank you