Oil Combi Boiler in Distress... and woman who owns it!

[Tibbot]

Question - what would be the symptoms if the expansion vessel was too small?

High expansion pressure, stress on joints, valves, air vents etc. The Worcester can accommodate about 100 additional litres of rad/pipes water (probably still not enough for you) if vessel pre-charge and system water pressure is at 0.5 bar. As most people used to being advised 1 bar for each, it's far safer to add another as it reduces this to about 40 extra ltr. In any case get yours checked first before anything else.

Jacket & store are parts of a Heatslave.

 

[oilman]

Interesting about the CORGI point. I've had a fair few heating engineers say they can't look at it becaise they aren't registered for oil fired boilers!

That is a euphemism for "I don't know anything about them".


No one has to be registered to work on oil fired boilers, or install them for that matter.

Expansion vessels are much less than £70 from www.bes.co.uk. There is only a minimum size needed, you can fit one as big as the house if you want.

 

[starkelwood]

Thanks so much for all of your comments. My last post on this:-

I gather from what you are all saying that in reality i probably need a new and larger boiler.

So, am I better off with a replacement combi boiler or back to a traditional cylinder job? ..or can I get away with an additional expansion vessel (sounds like not to me).

They are not particulalry small rads in the extension (3 downstairs and 3 upstairs - 2 rooms in extension but largish ones). It has quite a lot of glass so I sat and worked out (with help frrom Bisch rads calculator) how many BTUs I needed (bloomin' loads!!).

 

[Tibbot]

Thanks so much for all of your comments. My last post on this:-

I gather from what you are all saying that in reality i probably need a new and larger boiler.

So, am I better off with a replacement combi boiler or back to a traditional cylinder job? ..or can I get away with an additional expansion vessel (sounds like not to me).

They are not particulalry small rads in the extension (3 downstairs and 3 upstairs - 2 rooms in extension but largish ones). It has quite a lot of glass so I sat and worked out (with help frrom Bisch rads calculator) how many BTUs I needed (bloomin' loads!!).

I'd keep the boiler, but if you're prepared to contemplate such expensive decisions then you might consider sparing a more modest sum employing a competent person (heating engineer, not builder or bloke who plumbs for builder) to advise you properly.

 

[starkelwood]

I can't agree with you more. But you have probably gathered that i don't know who to trust really. Its the 1st oil fired boiler I've had; engineers I've been recommended and called don't seem interested; the guy who serviced it before I bought the house has retired; the 2nd engineer I used missed a major problem that the 3rd picked up and now the 3rd has also retired!

If you can recommend any experienced oil boiler/heating engineers in South Cheshire then I'd be delighted to know.
In truth I've had problems with this boiler since I bought he house 3 years ago but I've muddled through and it's got going again. This time it seems major surgery is required which is why I decided to consult the Forum before I called anyone in. Just trying to arm myself with some sensible questions and answers before I spend what I haven't got!
I do feel better equipped thanks to you all.

 

[Tipper]

Try the OFTEC web site to search for an 'oil fired' engineer/company.

OFTEC are the equivalent of CORGI/Gas Safe but for oil fired boilers, etc.

 

[RichardBothwell]

Most of the so called OFTEC oil engineers I know are clueless course cowboys.

 

[Burnerman]

The Heatslave 12/14 is good to work on though....easy to replace the PRV and AAV, EV too plus the 3 port valve top (had to do all of these this year!)
A canny little B9 burner too.
John

 

[oilhead]

You seem to have 2 problems
!2/14 probably too small for new system, particularly if you want to heat further away, hence cold rads. Also if builder has extended existing pipework, is it capable of carrying sufficient load. What size are the primaries, especially to the extension. If he has extende off 15mm Rads, then no chance.
The 10 litre exp vessel may be too small for the system, but if it's not going through the PRV, then it must be going somewhere else, you need to establish where the leak is, could well be from the auto air vent if the boiler has been drained down.