Ideal Classic LX RS260 Boiler Problems - help needed

[alastairpearce]

Hello,

I have had a problem for a few months now, where my boiler was overheating and pumping over.

Initially I thought it to be a circulation problem, but this has been discounted by undertaking a power flush and removing blockages in the circulating pipework.

I enquired with British Gas about Homecare, and subsequently made arrangements to have a repair done to fix the fault, as I now believed it was with the boiler.

Anyway, the engineer came around, listened to the problem occurring (boiler kettling and pumping over into attic), and then came to the conclusion that the heat exchanger in the boiler was clogged up with scale/sludge. The B.G. engineer stated that he couldn't fix the fault, and that rather than try and repair it it would be more wise to simply replace the whole system. B.G. subsequently quoted me £5.5k to have a combi system installed.

I know I could get a cheaper quote than £5.5k, but what I am wondering is if there is a cheaper solution than replacing the boiler. Other than this problem I think the Ideal Classic boilers are supposed to be pretty reliable? And my system has only just had this problem occurring after a long period of perfect operation.

I have attached an exploded view of the boiler

Untitled

• alastairpearce
• 4 Jul 2011
• 1

Untitled

• alastairpearce
• 4 Jul 2011
• 1

basically the BG engineer came to the conclusion that at the point where the boiler thermostat enters the heat exchanger, this is clogged with scale/sludge and hence the thermostat cannot sense the boiling water in the heat exchanger.

Possible solutions I can think of:
- Put a chemical (e.g. Sentinel X800) in the system and allow to circulate for a few days in the hope of freeing sludge/scale.
- Have someone replace the thermostat and heat exchanger if necessary.

I notice to heat exchanger has a drain plug on it - to what extent can I open the casing of the boiler and drain this myself? (I'm not a CORGI registered, so my gut feeling is that I can't do anything to the boiler).

Anyone experienced this problem, or have any thoughts?

Any thoughts would be really appreciated.

 

[Boilerman2]

Do you have a Fully Pumped system, or are there 4 water pipes connected to the boiler - which would indicate Gravity hot Water??

 

[45yearsagasman]

I'd bet that your "pumping over" is not caused by a blocked heat exchanger. This phenomenon is almost always due to pipework restrictions around the area where the cold feed and open vent connects to the system. To be sure that this section is clear, use a magnet to detect iron based blockages in the copper and if detected then these must be removed by cutting out the affected pipework and either cleaning or replacing the pipes. Powerflushing alone will NOT do the job. I have only ever replaced Classic heat exchangers because of leakage and not because of blockages. You don't say who did the powerflush? One test you can do is to run the system with the boiler stat set to off and see if the pumping over still occurs. If it does then its not the boiler. Pumping over and boiling over are not the same thing.

 

[alastairpearce]

Thanks for your reply.

Of course you are right, however I have been through the process of checking the airing cupboard pipework exhaustively. Any blockages I did identify were thoroughly cleaned out using pipe cleaning brushes, and the pipework was replaced. I have run the system with the boiler themostat set to off for a few hours, until it was running silently, that is until I believe there were no more air bubbles in the system. I honestly do not believe there are any blockages in the airing cupboard pipes now, as there is no magnetic attraction anywhere.

I may be misusing the term pumping over. In normal operation there is no water flow into the feed/expansion tank. When the boiler boils over, there is a sudden gush of boiling water/steam into the expansion tank, and it is this that the British Gas engineer believed was caused by a blocked heat exchanger. He seemed to think that the thermostat capillary tube could have been blocked/scaled up, which was preventing it from detecting the temperature in the heat exchanger, if this makes sense?

 

[shambolic]

Never had this with a classic that was caused by main heat exchanger ever. Take a note offlow and return temperature off the pipework to see the differential. Flow on right(on top of case at pipe you will have an F and R in front of pipes. Should have no ore than 20 differential as it getsup to max. If you have then pipework/pump etc circulation problem!

 

[alastairpearce]

The temperature differential is normal for the most part, but when the boiler starts to boil over obviously the flow temperature increases rapidly due to the boiling in the boiler. This is also true with the open vent pipe in the airing cupboard; as the boiler starts to boil over the open vent pipe becomes boiling hot extremely rapidly.

 

[45yearsagasman]

Alistair, It does after all sound like a temp related problem and I guess the only way to prove it is to drain and remove the heat exchanger and investigate further. It may well be a localised blockage but very hard to pinpoint exactly where. There's a good 3 hours work to remove and replace one of those exchangers. Depending on the findings it may not be economical to repair your boiler. £5.5k is rather high, but of course we don't know what the quote contains. It does sound like the system is clean and if all you need is a boiler replacement then £2k is about what a privateer would charge.

 

[alastairpearce]

So if the heat exchanger has a blockage, I'm guessing that as the problem has only recently started occurring the blockage can't be too severe?

If I were to use something like Sentinel X800 and just leave the pump running for a few days, without the boiler on, to circulate it around the system, do you think this would be effective in removing any blockages from the heat exchanger?

 

[Agile]

So if the heat exchanger has a blockage, I'm guessing that as the problem has only recently started occurring the blockage can't be too severe?

Customers always think their problems are simple!

If it really was simple then British Gas would have fixed it as they are reasonably good with simple faults!

What I cannot understand is that you had someone doing a probably fairly expensive power flush for say £350 but he did not investigate what was actually causing the problem and left you with the problem still there.

Whenever I do a power flush, I ensure that it is what is actually required and that I cure the problem!

Tony Glazier

 

[45yearsagasman]

Quote:- If it really was simple then British Gas would have fixed it as they are reasonably good with simple faults!
How bl**dy patronising is that.

 

[twgas]

It is possible that the thermostat is broken (I don't think anyone else has suggested this) maybe I've missed something that has ruled out the 'stat.

 

[Agile]

Quote:- If it really was simple then British Gas would have fixed it as they are reasonably good with simple faults!

How bl**dy patronising is that.

In this case the BG engineer seems unable to offer any fix for the problem.

His solution is a replacement boiler for £5,500 !

A figure most of us could easily reduce by nearly a half

I always offer a repair solution! But I also mention the cost of a replacement boiler as an alternative if the client seems interested.

 

[johnnojob]

Looks like you have an old but very reliable boiler unfortunatly young repair guys cannot trace a simple fault probaly to lack of experience,time allowed and need to sell new products.
The old boilers are here for a long time just like tony the agile engineer.

 

[Agile]

Older engineers usually rate the Ideal Classics as one of the most reliable boilers ever made.

By chance there is one in the house here. The feed pipe is rather blocked but the boiler still goes on strong.

 

[misterdubya]

It is possible that the thermostat is broken (I don't think anyone else has suggested this) maybe I've missed something that has ruled out the 'stat.

I was thinking that. I have seen it before.