Excessive Condensation?

[Rob]

I had a new condensing boiler fitted in April, and apart from being a bit noisy (a high-pitched whine) all's been well. However, I have noticed a puddle forming under the flue, and it seems to be turning into a problem. Here's a couple of pics:

've measured the water as about 2.5cl per 8 hours of c/h use. Is this about right? Also, it does seem to be a lot of water forming from a very small surface area - the lip of the flue. All the pipework seems water tight.

TIA, Rob

[Andrew Gabriel]

I can't see any reason the end of the flue is cut to form a water protection hood. It wouldn't matter if rain went down it (if it's been installed with correct slope back into the boiler). I suspect it's the condensation on that hood which is dripping off, and would be mostly solved if you cut it off. I presume it's just the exhaust and the air inlet is somewhere not visible in the picture?

My condensing boiler flue points up anyway. Once a year I pour a couple of pints of water down it to wash away any debris collecting in the bottom of the heat exchanger, which is much easier than opening up the heat exchanger, which then always needs new seals. (I don't know if that's safe for all condensing boilers though, and never pour water into the air intake.)

[Rob]

Yes - condensation forms on the hood and drips down. I assume it's an exhaust only (Ideal Logic+) although I hadn't thought about where it gets its air for combustion - the room?! There's no inlet I can see.

Maybe cutting the flue's the way forward. I'd better get the installer back because it's damaging the patio. I just wanted to pre-empt a 'They all do that, sir' type discussion.

Rob

[Lobster]

Gas installers get very twitchy about doing anything at all to manufacturer-supplied flues, even something as seemingly innoccuous as trimming this hood affair.

My previous boiler was an early condensing model, built before the current existing plethora of flues were available to deal with awkward plumes - like the one in the OP's photos. My plume was directed towards paintwork on the adjacent garage, so I fabricated a sheet metal deflector and postitioned it several inches away from the opening of the flue, to divert the water vapour diagonally upwards. Got a flea in my ear from the CORGI man for that one - though I really can't see what possible harm could have been done by it.

Could the angled end of the OP's flue simply be rotated 180 degrees to solve the dripping problem?

David