Dripping combi boiler - any ideas?

[dangemrod]

We've just bought a formerly neglected house "in need of some attention". The other day I noticed some water very slowly dripping through the metal vents in the bottom of our combi boiler.

It used to frequently overheat, which I put down to a drop in pressure after removing and replacing a radiator. I refilled and got the pressure up to a fairly steady ~1.25 bar. No more overheating, but now I've noticed this drip.

I'd be grateful for any advice on how to diagnose/fix this, since the words "boiler" and "plumber" in the same sentence fill me and my empty wallet with dread.

[Lobster]

Could be anything - you need to get the front off (isolate the power) and work out where it's leaking from. Might be as mundane as a nut which needs tightening, or it could be as bad as a new boiler job.

David

[Stuart Noble]

Digital cameras can be quite handy for inspecting things in inaccessible places, especially as the flash tends to highlight the wet bits.

[John Stumbles]

Though you'll be lucky to get it in focus.

I use a small mirror (handbag size i.e. wot a lady would carry in her handbag) and a torch. Candidates are the auto air vent at the top and any clip-on joints sealed by O-rings. Can be a PITA to get sealed again. What boiler (make & model) is it?

[dangemrod]

It's a worcester bosch 240. Got the front off, but don't have a great idea of what I'm looking at (even with camera/mirror assistance; boilers are a mystery to me)

[John Stumbles]

Bosch, or just Worcester? I think it's an earlier name for the 24CDi. I had a CDi recently that was leaking from where the hot water out pipe (the only one without a screwdriver-operated valve on its connection to the boiler IIRC) connected to the plate heat exchanger. The connection is made by the pipe just being pushed into the PHE with a rubber O-ring to seal it, which had gone hard.

You can get the manual if you haven't got it already from

Got the front off, but don't have a great

You're looking for where water is coming out :-) Can you see drops of water forming somewhere? There may be a tell-tale trail of limescale below it.

[John Stumbles]

Pics and stuff here

[John Stumbles]

Looks like the 240 has a quite different heat exchanger from the 24CDi so ignore what I said about leaking push-fit connections. If it uses the old cast-iron heat exchanger like the CBi it could be leaking from that. If that is leaking it's a major job to strip down but you may not need a new heat exchanger (which costs about £200) as there are steel blanking plates at the right-hand end of the heat exchanger (opposite to where the flow and return pipes connect) and it may be leaking from where these plates join the cast iron lump. Should be possible to fix that.

[Stuart Noble]

I use mine for reading the electricity meter under the stairs. Working out what those dials say is difficult enough without being on your knees with an ironing board leaning on you. The focus is spot on due, I presume, to the double flash thing. One to get the focus and one to take the picture. No good for action shots, but perfect for this

[dangemrod]

Thanks for this. I'll do a proper investigation this evening and post what I find...

[John Stumbles]

Neat! Mine isn't as clever as that (and positively demented when trying to take long-distance shots in low light: it *knows* from the auto-focus that the subject's too far off to illuminate with the flash but it still fires anyway, then spends ages recharging the damn flash before you can do anything even if you just want to switch the flash off and have a go with available light.)

[Clive Mitchell]

In message , Stuart Noble writes

I use mine for taking photo's up skater dudes baggy shorts, but sometimes they see me and hit me with their skateboard.

[Lobster]

Did you know that's why camera phones (or at least Japanese ones) have an audible 'shutter release' which you can't disable, because apparently a proportion of Japanese men have a particular predilection to directing them up schoolgirls' skirts on the subway.

David

[Clive Mitchell]

In message , Lobster writes

No problem. One snip and the camera's mute.

[Thomas Prufer]

On a phone camera, that might be a problem.

Thomas Prufer

[Stuart Noble]

Please post detailed instructions urgently :-)

[dangemrod]

Apologies for the extreme lateness of the post, but - if anyone is still interested - it turned out the leak was coming from the divertor valve which had eroded to the extent it needed to be replaced. So not as quick or cheap as tightening a nut, but vastly preferable to having to replace the boiler!