Old combi losing pressure - advice sought

[lxndr]

I have an old Vaillant combi bolier, I think it's a VCW 242 EH which in general has given me little trouble. Over the last few years though it has started losing pressure and has got to the point where it's a real nuisance and needs topping up every time it's used.

I got a CH engineer to come take a look at it and he replaced a part (maybe the heat exchanger?) and charged me £250. What worried me at the time though was that he didn't appear to test anything or attempt any diagnosis or even look closely at the rad valves, just kept saying that this part needed replacing and was likely to blame for the pressure loss.

Anyway, following the repair the pressure loss is exactly the same as it was. The pressure usually drops by about 0.4 bar each time the heating is switched on. There doesn't appear to be any pressure loss if the heating is not switched on or, as far as I can tell, when hot water is being produced.

So, basically, I'm unsure what to do next. I could resign myself to having to get a new boiler fitted although I would really struggle to find the money for that right now. I could get the same engineer back in but I'm less than confident that he knows what he's doing or can "problem solve" in order to determine what the problem is. And I suppose the last option would be to start over with a different engineer to try and repair it again.

Would really appreciate any advice from those with a far better knowledge and experience of these things.

__

 

[Boilerman2]

Has your Engineer checked the Expansion Vessel? (it's behind the boiler)
if this has no air in it the water in the system can't expand when heated and so will leak out via any poor joints or the saftey valve discharge pipe.
it is possible to cut in an additional vessel somewhere near the boiler on the return if this is easier and would probably be cheaper as well

 

[lxndr]

Has your Engineer checked the Expansion Vessel? (it's behind the boiler)
if this has no air in it the water in the system can't expand when heated and so will leak out via any poor joints or the saftey valve discharge pipe.
it is possible to cut in an additional vessel somewhere near the boiler on the return if this is easier and would probably be cheaper as well

I did some very basic research on the internet at the time and suggested it to him and he simply dismissed it. Given that I personally have absolutely no knowledge of boilers I wasn't really in a position to debate with him. Do you think I should get him back in again and insist that he check it ? Any idea how much he is likely to charge for such a test?

 

[Boilerman2]

From the sounds of it I would advise that you get someone else to have a look maybe a heating MAINTENANCE engineer? I can't believe that the Expansion vessel was not the first thingh he would look at

 

[compheat]

The domestic heat exchangers do corrode on this model, but if it is your expansion vessel its not a difficult job to do, that's if it only wants recharging
but if the diaphragm is spit it will need replacing.

where about in cheshire are you

 

[compheat]

Although this boiler is reliable it is also expensive to repair

 

[lxndr]

The domestic heat exchangers do corrode on this model, but if it is your expansion vessel its not a difficult job to do, that's if it only wants recharging
but if the diaphragm is spit it will need replacing.

where about in cheshire are you

I'm in Sale.

What I'm trying to avoid is sort of throwing good money after bad .. I'd prefer to try and have the boiler repaired but don't want to keep throwing money at it and still end up with a faulty boiler.

 

[compheat]

The expansion vessel is located at the back of the boiler.
It as a connection on the top the same as a car tyre, if you take off the dust cap and press the inner section of the valve it should release air, if it releases water its behold repair and if nothing comes out then its lost its charge and wants re pressurising.

hope this makes sense

 

[lxndr]

The expansion vessel is located at the back of the boiler.
It as a connection on the top the same as a car tyre, if you take off the dust cap and press the inner section of the valve it should release air, if it releases water its behold repair and if nothing comes out then its lost its charge and wants re pressurising.

hope this makes sense

Many thanks for the advice, appreciated. I have the boiler under the stairs and haven't as yet been able to try what you suggested but hopefully once I've emptied the area I should be able to get at it .. I did manage to get my hand round the back of it tho and think I could feel what you were referring to.

Do you know what sort of cost I would be looking at if the expansion vessel needed replacing?

Best wishes,

Ian

 

[Boilerman2]

If the boiler is under the stairs it would be easier to fit a standard 12 ltr vesse to the heating return pipe near to the boiler, this would negate the need to remove an old boiler from the wall which would risk further damage or problems afterwards expect to pay an engineer about £120+vat to supply & fit a Vessel

 

[lxndr]

If the boiler is under the stairs it would be easier to fit a standard 12 ltr vesse to the heating return pipe near to the boiler, this would negate the need to remove an old boiler from the wall which would risk further damage or problems afterwards expect to pay an engineer about £120+vat to supply & fit a Vessel

Given that I'm pretty much clueless in regards to boilers in general I just want to make sure I've understood correctly. If when we test the expansion vessel it just needs repressurising could that be done without removing the boiler?

And if it needs replacing I could instead have a vessel fitted outside of the main boiler?

How much is the repressurising likely to cost, the reason I ask is I'm trying to decide whether to abandon repair and buy a new one. In general though, the boiler has worked well so I'd prefer to get it fixed if possible.

 

[kevplumb]

if you look in the FAQ at the top of the forum you can test/ repressurise yourself

yes you can have an external ev

repair it (good old beast)

 

[lxndr]

if you look in the FAQ at the top of the forum you can test/ repressurise yourself

yes you can have an external ev

repair it (good old beast)

Thanks for directing me to the FAQ which I've taken a look at now. Unfortunately, I'm pretty hopeless at these things and I don't think I'd be able to do it myself. I'll make another post and see if there's anyone in the area (Manchester / Cheshire) who might be interested in doing the job.

 

[lxndr]

Just to follow up to say that I did eventually manage to get at the dust cap of the expansion vessel. Pressed the pin and unfortunately water came out. So now I'm looking to get an external vessel fitted. Have called 3 engineers from the Thomas Local .. none were interested. Is this a particularly difficult job ... any recommendations for an engineer in the Manchester area who might be interested in carrying out such a job?

 

[BlueMoonMole]

The 3 you called won't be interested because there's not much money in it.

I'll ask a friend at work if he's interested.

I'd do it myself but I go I'm off on Holiday for a week

TBH, it's a fairly easy job to do.

You'd probably be able to do it yourself, using compression fittings and a bit of advice.