Heating issue

[im4it]

Help, my combi boiler is doing my fruit in! I've read the forum about radiators being warm when the heating is switched off and then replaced valve but ours is similar but not sure what it is.

We have a combi which does the water and heating on the same switch and clock. And a room stat in the hall and above the boiler a frost stat. A guy fitted a valve as it had stuf and evrything was ok for a short time. then this happened:

The boiler rocker switch was switched to water & heating. The timer in the airing cupboard had power to it but was not activated or timed to come on. it was in the off mode. Then the room stat was was on low. At about 2.30am in the morning (when it was supposed to be off and was not timed to come on) the heating sparked up and was heating the whole house. Even switching the room stat down, the heating remained on. the only way to switch it off is via switching the power off to the timer clock and shutting the system down or to go and switch the rocker switch just to water setting. When it is hot, the room stat has absolutelty no control over switching the boiler on and off and bringing the temperature down. i.e the pump can still be heard pumping water and only way to get it to stop is switch the whole thing off.

Any ideas as our boiler man hasn't a clue and we had to pay him for stuff done so far! He has changed the valve in the boiler as it was stuck so that should have eliminated that one. Any help here would be much appreciated!

 

[mickyg]

what boiler is it?

 

[im4it]

it's a worcester combi boiler! i will try and find the model. its about 5-6 years old.

 

[tonybhoy]

it's a worcester combi boiler! i will try and find the model. its about 5-6 years old.

Excellent that narrows things down a tad to about fifteen boilers

Sounds like a thermistor fault, possibly one that also controls the boiler's internal frost stat but your going to have to isolate the external controls to check the boiler.

 

[im4it]

Hi Thanks for all your help. I have checked the make and model which is a worcester heatslave 15/19 and has an Ikon room stat and an ancient honeywell frost stat. I just read all the posts in the forum about frost stats and then went down and checked mine. And tt was set at 26 degrees!!!! me thinks this might have been the problem and why oh why my boiler man never checked this i will never know. Perhaps it was the cash in his hand that did it. This is a fab forum and would trust this for sure now! i'm gonna check the operation out now as it totally makes sense. my boiler is in the garage, so at night when the temp would have possibly gone below 26 degrees the boiler will have fired and kept on firing!!! Making the house like the bahamas and the garage like a sauna! I even think the fault may have been caused by said boiler man twisting the dial round like he was trying to get radio 1! The problem has only come about in recent weeks with the weather changing and being on holiday we hadn't noticed, so i think that will be it. Being a novice at these things i feel like quite an expert with several good people assisting me on here! Well done..keep up the good work! If it's not that then might have to go back to the old back back boiler on a fire! he he he

 

[Agile]

It sounds as if the boiler is experiencing a continual hot water demand.

The DHW demand switch needs checking.

Why are you employing someone who "does not have a clue" ?

With a boiler like that you must be out in the sticks. There is a little Indian restaurant in the old town in Telford where you can take your own wine!

Tony

 

[D_Hailsham]

It sounds as if the boiler is experiencing a continual hot water demand.

The DHW demand switch needs checking.

Why read just the first post? If you had read the OP's last post, sent a few minutes before yours, you would have seen that he had solved the problem - frost stat set to 26°C

Why are you employing someone who "does not have a clue" ?

Maybe the installer did know what he was doing and deliberately set the frost stat high so he got called back a few times.

Luckily the OP was sensible enough to post here and managed to sort it out himself.

 

[Agile]

Have you considered that I started to compose my reply before his was posted?

Whilst I type quickly, during the evening I can be talking, eating, drinking and watching TV as well as answering the odd forum question.

In the absence of a mal-adjusted frost stat, my suggestion was the most likely!

Tony

 

[D_Hailsham]

Have you considered that I started to compose my reply before his was posted?

Been there and done that.

Whilst I type quickly, during the evening I can be talking, eating, drinking and watching TV as well as answering the odd forum question.

All at the same time? That's impressive.

In the absence of a mal-adjusted frost stat, my suggestion was the most likely!

Both just a likely.

I have done the same, so now I tend to have the topic open in another tab so I can see any replies which arrive while I am composing my reply. I have often abandoned a post when I see someone has posted while I am writing. It also means I can review/copy from more than just the last page of a topic.

 

[Agile]

A seriously mal adjusted frost stat is not an expected cause of a fault because that has been done intentionally for some reason either maliciously or by a nupty. Something to be checked if attending the boiler though.

Showing multiple tabs is good but needs setting up and my computer is already far too slow. However, my computer does not show additions to a posting unless I refresh the display! How do you do that?

What I would find more useful is a second computer to show boiler MI as I currently make all my replies without consulting the MI with the sole exception of Vaillant codes.

Tony

 

[kevplumb]

unless I refresh the display! How do you do that?

tab at the top tony depending on your browser mine is next to the back icon

might be reload

 

[D_Hailsham]

Showing multiple tabs is good but needs setting up and my computer is already far too slow. However, my computer does not show additions to a posting unless I refresh the display! How do you do that?

Multiple tabs should not make any difference to performance. To refresh a page (IE)you can either press F5 or the double arrow icon at the very top of the screen. Can't remember Firefox (probably the same) as my other PC is out of action at the moment.