Alpha CB50 Boiler exploded today

[lawrenso]

Depending where you live I'll come and unplumb the Alpha and take it away. Then your installer has less work to do.

and how much for my back pocket

 

[lawrenso]

Here is some pics for you. I made a mistake before - the valve replaced comes off the storage tank.

Untitled

• lawrenso
• 29 Dec 2008
• 1

Untitled

• lawrenso
• 29 Dec 2008
• 1

Untitled

• lawrenso
• 29 Dec 2008
• 1

 

[BigBurner]

Cheers for ALL the replies. A bit of further information for you. As mentioned in my earlier post we have had a few problems with this boiler and also a few problems with British Gas. They took payments from me without arranging a take on inspection, then when I called them out after 11 months, they came and at first tried to refuse to take on the boiler saying it was BER, would take too long to fix (had corrosion around the top inlet on the storage tank, running outside). I had to quote Contract Law at them - then they came out and only replaced funny enough the PRV from the said same expansion vessel - all of 10 minutes!!. This was dripping to the outside and was pointed out to him by her indoors and the engineer said that it was OK!!

We then had to have the storage tank replaced a couple of months ago due to it leaking from the top valve where the corrosion was - this would of meant removing the expansion vessel. - which he re-secured with a bit of nylon washing line and he lost the screws for the front cover to be rescured on - telling the misses I said I would do it later!!

The Transco guy pointed out to me that the overflow pipe was frozen as to the cause. I have a nice chunk of ice with pebbles in it (the overflow is about two inches above ground level and it had an icicle down to the ground into the pebbles around the house). The BG engineer then said that wasn't the cause of it!!

They are due tomorrow with the spare parts and a boss as well as an engineer and I will be looking for somebodies scalp over this. I also want a complete and thorough investigation into the complete boiler.

At the end of the day one of us could of been in the garage when it went.

I would be inclined to agree wit the Transco man that the ice caused the explosion. Have the discharge pipe lagged. I would still have another PRV teed into the CH pipework near the boiler.

I would get them to size up the expansion vessel properly. It appears the internal one was not big enough and an addition vessel should have been fitted.

 

[swbjackson]

Lagging the discharge pipe won't make any difference. The problem in this instance was caused by the water dripping onto the stones and freezing, this built up until it reached the bottom of the pipe and started freezing back up the pipe.

Looking at the damage to the pressure vessel I would be concerned what damage has been done elsewhere within the boiler due to excess pressures.

Mike

 

[The Baker]

Should it prove beyond economic repair you may want to consider one of these.

http://www.rinnaiuk.com/Updates-18-09-08/A4 Twin Flow.pdf

Tim

 

[lawrenso]

Right - BG just been - replaced the vesel and another PRV valve - but have left us with an "at risk" boiler because the overflow has been fitted wrong - should be into a tundall (excuse spelling or phrase) and then a 22mm pipe going to outside - does this sound right? However my wife is extremely worried about it now and has just had me switch off the boiler.

Cheers

Steve

 

[Agile]

The PRV vent pipe should have terminated 6" above ground level. That would greatly have reduced the chance of ice blocking.

The PRV should not have been leaking and would either be leaking because:-

EXV too small to accommodate expansion in rads.
EXV wrongly charged with air.
Dirt on PRV seating
Filling valve left open or leaking.

None of those would be the fault of British Gas as they are installation/user problems.

Dont expect top notch engineers from British Gas. They have to get what they can and rely on the senior fellow to deal with any problem they cannot manage.

In your case I take the view that you were unreasonable in expecting BG to cover aspects of your substandard installation which they would not usually cover. Yes, I know they failed to make the initial inspection but you have unreasonably capitalised on that. I presume that you are one of those unpleasant people who go round sueing anyone you can!

Tony

 

[BigBurner]

Right - BG just been - replaced the vesel and another PRV valve - but have left us with an "at risk" boiler because the overflow has been fitted wrong - should be into a tundall (excuse spelling or phrase) and then a 22mm pipe going to outside - does this sound right? However my wife is extremely worried about it now and has just had me switch off the boiler.

That is not a show stopper. It just needs a "tundish" fitted to the cylinder pressure relief pipe. But, if the relief pipe is in a position where any discharge can be clearly seen then it is realistically not needed. The idea of the tunish is to see any water discharging to alert the user. If they say get one fitted as the instructions say so then do it. As the boiler is in a garage there should be no problems. Use it. BG are covering themselves. They took the system on, and should have inspected it, so they should put it right.

Your boiler (CH) discharge pipe. Where does it run - what route? How much outside?

BTW, this problem would have happened to any make of boiler: system or combi, if fitted like the Alpha is. The exploding vessel was proving the last line of defence worked.

Get the Tundish and CH pressure relief pipe sorted (lagged as in a garage) and all should be fine as you have had a lot of expensive parts fitted.

The instructions clearly show how the tundish should be fitted:
http://www.alpha-boilers.co.uk/prod...r_installation_and_servicing_instructions.pdf

 

[BigBurner]

Lagging the discharge pipe won't make any difference. The problem in this instance was caused by the water dripping onto the stones and freezing, this built up until it reached the bottom of the pipe and started freezing back up the pipe.

Looking at the damage to the pressure vessel I would be concerned what damage has been done elsewhere within the boiler due to excess pressures.

Mike

The expansion vessel is designed to blow, and all other components in the system be OK at the blow pressure.

If a relief pipe is running down a wall outside, it is possible that at an elbow through the wall to outside attached to the downwards pipe will freeze at the elbow. That may be 3 to 4 foot up the pipe. A small drip collecting here at sub zero temperatures will freeze and block the pipe. Lagging the pipe and keeping the discharge pipe inside for most of the run will prevent this.

 

[BigBurner]

In your case I take the view that you were unreasonable in expecting BG to cover aspects of your substandard installation which they would not usually cover. Yes, I know they failed to make the initial inspection but you have unreasonably capitalised on that. I presume that you are one of those unpleasant people who go round sueing anyone you can!

Tony

This one is a fool and insulting a man too.

BG should have inspected the system, if substandard installation then they inform the user what to do to bring up to standard. If they do not then they pay up when things go wrong.

The OP has done nothing wrong. He had BG service his boiler and it blew up.

 

[lawrenso]

The PRV vent pipe should have terminated 6" above ground level. That would greatly have reduced the chance of ice blocking.

The PRV should not have been leaking and would either be leaking because:-

EXV too small to accommodate expansion in rads.
EXV wrongly charged with air.
Dirt on PRV seating
Filling valve left open or leaking.

None of those would be the fault of British Gas as they are installation/user problems.

Dont expect top notch engineers from British Gas. They have to get what they can and rely on the senior fellow to deal with any problem they cannot manage.

Thanks for the advice above - however

In your case I take the view that you were unreasonable in expecting BG to cover aspects of your substandard installation which they would not usually cover. Yes, I know they failed to make the initial inspection but you have unreasonably capitalised on that. I presume that you are one of those unpleasant people who go round sueing anyone you can!

Tony

I am not a plumber/fitter what ever. I took out a BG contract because they are. I do not know what should be done or not done. I pay them a monthly fee for that service. I do not however just take things at face value and use forums like this to consult with professionals like yourselves - but not to be insulted. For example - I have also been onto Alpha themselves this morning and they have confirmed that it has not been installed correctly as BG have pointed out. I have also contacted Corgi and been informed that come back would only be for a 3 year period to get the job rectified. I am not going to be suing anybody - but that would be a different story if anybody had been injured. All I want is a safe installation for my family - what is wrong with that please Tony??

I would like to say thank you to everybody who has made constructive comments on this matter. My wife is very worried about the safety of our current boiler and we will definately be looking to replace this in the very near future now - so your recommendations will be mostly appreciated and also rough estimations of costs etc for the boiler plus installation. If anybody is interested we are in the Chester area - Thankfully not near Tony's neck of the woods

Cheers

Steve

 

[BigBurner]

Stay with it. As I said it would have happened to any make of combi or system boiler. Get:

• The water cylinder pressure relief pipe and tundish sorted
• The CH pressure relief pipe sorted and lagged
• The existing expansion vessel sized up to see if an extra vessel should be fitted

Then it should be OK 100%.

 

[Agile]

Your boiler is fine and is now on a maintenance contract.

All it needs are two very minor modifications to correct installation defects.

A tun dish which gives a visible indication of a discharge AND an opportunity to allow the discharge to overflow if the outlet became blocked by ice etc.

The PRV vent pipe to be lagged or re routed or to have a tun dish added close to the boiler.

These would take less that an hour to fit.

Otherwise the boiler is fine and does not need changing.

Tony

 

[namsag]

BG Have recently changed there policy on blow off valves and termination of them (ie at risk) which is why nothing would have been mentioned before.
That must have made a hell of a bang when it went

 

[Agile]

I once was at a system with a failed expansion vessel and the pressure went up to 6 Bar as I watched it heat up.

I rushed for the PRV which had jammed closed and as I did that the owner told me the EXV was leaking.

When the pressure was reduced the EXV stopped leaking and never needed to be changed. It had just distorted within its elastic limits and resealed when the pressure was released.

Tony