British Gas C1 / Worcester 28si - Strange fault...

[AKN]

Hi all,

I have an interesting fault with this boiler.

DHW running fine until the boiler "thinks" it's too hot and somehow dumps the contents of DHW into the CH loop,nswitches off the burners and restarts the ignition sequence as per normal.
DHW runs cold for a short while until returning to temperature.
This happens whether CH is on or off.

All thermistors are will within tolerance
Water flow rate is around 9-10 Litres/min at the HW tap-end
Fan up to speed and Air pressure switch working fine.

This continues ad infinitum... Unless the DHW temp control is set to minimum. Anything above min, say 25% plus, the fault manifests itself again.

Needless to say, the pressure in the CH system constantly reaches to a point where the PRV releases water via the runaway. There seem to be no other leaks into the CH.

Increasing the incoming water flow reduces this problem somewhat, so that the time it takes to dump water into the CH loop is extended. Of course the water temp will be a little lower due to the increased rate of flow.

Is there some invisible diverter/dump valve that I seem to have missed or some unique function of the HX? Or a faulty HX, even?

Kindest regards and TIA.

 

[fixter1]

are you gas safe????

 

[AKN]

Hi Fixter1,

No, this is my own boiler...

 

[fixter1]

dose the pressure go up when heating is not on.. let pressure out of the boiler and leave it empty see if it fills up on its own

 

[SimonJohns]

You'll need a GSR

It's a very simple fault. Won't cost you much

 

[AKN]

Hi Fixter1,

Yes it does as the hot water is somehow dumped into the CH. The PRV kicks-in at around 3bar..

 

[fixter1]

iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii

 

[AKN]

Thanks Fixter1...

Interesting... It only happens in a condition of an "overheat" rather than a constant transfer of hot water. When the water temp is kept at its lowest temp, leaving the tap running does not increase pressure in the CH system.

If this is the case, I feel a call-out coming on, though swapping out an HX safely isn't rocket science. Then again, Worcester's fixed-fee fix is less than some places charge for an HX.

Thanks!

 

[fixter1]

????????????????????????????

 

[SimonJohns]

it could be a blockage like i say i could be wrong get someone to have a look at it keep us informed of the outcome

I think you need to stop giving advice. I was decent to give you the answer. I don't expect you to relay that

I have worked very hard. And studied and researched about boilers and their principles of operation.

This is just encouraging others to play with an appliance that isn't safe for them to do so

 

[AKN]

Many thanks to Fixter1 for being most helpful. It's a shame you've been forced to render this thread useless and I'm sorry your willingness and genuine responses of assistance have to be policed. As you know, I only wanted some guidance in order to make sure whoever comes out is looking in the right area. I know my limitations.

It's easy to describe faults as simple and cheap to repair without qualifying what is simple and what is low-cost...

I'm not sure keeping this thread alive by posting the outcome will be of benefit, in case it contains trade secrets that others won't want shared. Unless of course it's disguised by Gas Safety small-print and Non-disclosure agreements!!! ;-) I'll most likely PM you when it's repaired, Fixter1.

Perhaps all questions need to be prefaced with the originator's technical qualifications and abilities before anyone decides that no one except they are smart and qualified.

Something for SimonJohns to ponder over:

So in the Libyan fable it is told
That once an eagle, stricken with a dart,
Said, when he saw the fashion of the shaft,
"With our own feathers, not by others' hands,
Are we now smitten."
[h=1]Aeschylus[/h]Kindest regards
AKN

 

[Dannypipe]

We don't want to encourage DIY boiler repairs. So save all your Libyan fables for someone who cares.

We have a section for trained individuals to talk about boiler repairs amongst other professionals without joe blogs reading it, breaking out his tool box from the shed, and hurting someone. It makes me laugh how people who consider themselves intelligent but aren’t trained, think its ok to tinker with something that burns a fossil fuel in their kitchen. DUUUH.

 

[SimonJohns]

The reason for my disgust is that I sent the issue to fixter. As he asked what the issue might be

Being the nice guy that I am. I told him. But he has been on the forum for awhile. And previous to me telling him. He had no clue. So I was very annoyed to find him posting my answer

And I know what the answer will be when posted back

Good luck

 

[AKN]

Dannypipe:
Well, I'm grateful to all of you guys, even the ones that don't care for fables. It hurts to think...

As for discouraging DIY repairs, I completely understand, but your conceit of "people" is arrogance manifest.

SimonJohns:
Your disappointment is fair, though it would have been better said in private rather than an open forum.

As for me, I'll bow out before my own blunt arrows return.

Thanks all.
Adios.

 

[fixter1]

think we need to chill out now,,, and i did no the answer i was just checking,,,im still learning every day how am i ment to learn off the site if no ones willing to give the answers in the first 6 months of joining i was learning all the time lookin back at posts now all i see is get a gsr in,,,, i understand we dont want diys and simon johns u could of pm/ed me