Worcester Combi - 2 issues

[Mattenstein]

Hi people

We have a Worcester Combi installed by British Gas, which they have called a British Gas 532/i. It has always been under their own central heating care scheme (you'd think we were made of money!), however I am after some advice from independent sources.

There are 2 problems with the system:

Problem 1 has only arisen in the last couple of months; I have noticed that when I remove the base panel of the boiler to top up the pressure after bleeding it, there is a rust-coloured stain and some sludge on the underside that must have dripped from the boiler. Any ideas what this could be?

Problem 2, which has always been present and is the reason I frequently have to bleed air off and top pressure up, is to do with the bathroom towel warmer. It is the towel warmer I have to bleed as the top of it is the highest point on the system and a ridiculous amount of air accumulates there, so it is only half warm when I get around to sorting it out. BG have told me it is 'bound to happen' but with the inconvenience I hope it's something fixable.

I have now noticed that when I am in the bathroom upstairs and can hear someone running a (presumably hot) tap in the kitchen below, there is a noise of air bubbles rising through the towel warmer. Is this how it gets so much air inside and would that be caused by a problem with the boiler's heat exchanger?

Thanks for reading, hope someone can help!

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[Gasguru]

There's a leak in the boiler which is dripping onto the lower cover panel.
If it's rusty coloured it would indicate the systems not in great condition...ie. there's corrosion going on.

Continual bleeding of a radiator on a sealed system would often indicate a leak somewhere on the system.

You policy will probably not cover damage from corrosion or fixing leaks from inaccessible pipework.

Continual topping up of the system is gradually killing it off.

 

[Mattenstein]

Thanks for your reply.

That's both interesting and worrying.

BG powerflushed the system and would have, I would assume, been aware of any corrosion when the boiler was replaced. Also I have made a number of engineers aware of the regular need to bleed air off and top it up; none of them seemed too fussed and often they just said "Yeah it doesn't surprise me..." or such like. One even helped me to do this when I had called him out because I thought I shouldn't have to! So if I've inadvertently knackered a system they initially signed off as 'fine', by doing something they were aware of, surely I can't be held accountable?

The boiler is serviced annually and has up til now been 'in top shape', so should I have just plodded on with a half-useless towel rail??

Hey ho, I will get another of their 'experts' out and see what they say...

 

[gasright]

There's a leak in the boiler which is dripping onto the lower cover panel.
If it's rusty coloured it would indicate the systems not in great condition...ie. there's corrosion going on. WRONG!!!!!!

Continual bleeding of a radiator on a sealed system would often indicate a leak somewhere on the system. WRONG!!!!!!!!!

Two incorrect answers there.

 

[Mattenstein]

What's your theory then?

Personally I don't think the system was leaking prior to this boiler leak. Normally as the air accumulates in the towel warmer, the pressure gauge goes up, so the air is compressing the water rather than replacing it, right? It's only on this occasion the gauge was normal (around 1 bar) when I had to bleed a half-cold towel warmer.

Also nobody has mentioned the fact that the air seems to get in there while the DHW is running...

 

[Sully2014]

There's a leak in the boiler which is dripping onto the lower cover panel.
If it's rusty coloured it would indicate the systems not in great condition...ie. there's corrosion going on. WRONG!!!!!!

Continual bleeding of a radiator on a sealed system would often indicate a leak somewhere on the system. WRONG!!!!!!!!!

Two incorrect answers there.

Very odd response??

What would be the reason for the above?

 

[Gasguru]

There's a leak in the boiler which is dripping onto the lower cover panel.
If it's rusty coloured it would indicate the systems not in great condition...ie. there's corrosion going on. WRONG!!!!!!

Continual bleeding of a radiator on a sealed system would often indicate a leak somewhere on the system. WRONG!!!!!!!!!

Two incorrect answers there.

Well since gasright works for BG he's bound to defend BGs action and slag off anyone that offers contrary advice. There are clearly issues with this system that the BG "engineers" that have attended are dismissing. Sealed systems should not need regular bleeding. I've installed plenty of quality systems that never require bleeding. Of course the apparent trapped "air" could be other gasses due to chemical processes but that's unusual.

 

[doitall]

There's a leak in the boiler which is dripping onto the lower cover panel.
If it's rusty coloured it would indicate the systems not in great condition...ie. there's corrosion going on. WRONG!!!!!!

Continual bleeding of a radiator on a sealed system would often indicate a leak somewhere on the system. WRONG!!!!!!!!!

Two incorrect answers there.

A sealed system should never need bleeding after the intitial oxygen is out from the fresh water, so any air or loss of pressure indicates a leak.

If the system water is red/orange colour then it is corrosion, staining a piece of metal or pipe a rusty colour means nothing.

From what the OP is saying about the bubbles etc in the towel rail etc, it sounds like the plate hx is pinholed.

 

[Sully2014]

Well regardless of you being right or wrong you offered an opponion!

The benefit of this site is that non trades people can get advise and if it is wrong then ok, most issues require problem solving but for a fellow gas engineer to just say wrong doesnt really help anyone! id have thought gasright would have said what he thought the problem was??

 

[gasmarc]

sounds like you need a Fernox system health check where they check your inhibitor in the system if there is any

 

[Blooflame]

Well technically Gasright may have a point, however it's not what you say it's how you say it. That said I'd wager Mattensteins diagnosis is right. I left BG last year (phew!). There has been a constant issue from engineers about installs. One bloke can't powerflush a system and fit a boiler in one working day correctly. That's what's happening with BG. There have been some awful results that are compromising to say the least. Gasright should show a bit of respect as all we try to do here is help folk. The "air" you are bleeding is most probably Hydrogen - a by product of corrosion. I suggest you pay a third party to have a sample taken and tested by one of the major companies. make sure the filling loop is off, I had that recently where EON hid an underfloor leak by leaving the filling loop on on a pressurised System boiler.

 

[bengasman]

There's a leak in the boiler which is dripping onto the lower cover panel.
If it's rusty coloured it would indicate the systems not in great condition...ie. there's corrosion going on. WRONG!!!!!!...

The boiler was installed by BG and maintained by BG, so one would expect it was done to spec including cleaning/flushing of the system to spec.

I'd be most obliged if gasright could explain to me:
1. Where is the water coming from if there is no leak?
2. Why is the leaking water brown if the system was cleaned and there is no corrosion?

 

[Jamespl]

The rusty coloured water sounds like a leak on the boiler.

 

[ScottishGasMan]

"Air" building up as fast as you describe on the towel rail is not ok on a sealed system, the only two normal explanations for this is a micro leak on the system and the pump draws air in through this micro leak and the towel rail is simply the most convenient place for it to gather. Or you have a certain amount of corrosion in the system resulting in a hydrogen build up in the towel rail, which could also explain the "dirty " leak from the boiler, if hydrogen build up is a possibility then there are methods for proving if its air or hydrogen.

Either way, apart from a clean dribble of water after removing the filling loo key, there should be no wAter appearing below the boiler or on the bottom Tray.

 

[Mattenstein]

What Jamespl said (before edit) is exactly what the BG engineer said regarding the leak, residue from the boiler's internal air escape.

Now I wonder why he edited??

Any road I will accept that the likelihood is I have a leak somewhere on the system, the only thing is it is nowhere noticeable :/ The reason the air collects in the towel rail I'd assume is because it's the highest point of the system.
Interestingly the BG engineer didn't say anything about the colour of the aforementioned residue from the leak.[/quote]