Boiler Condensate

I have a Bosche Greenstar Condensing Boiler. It is installed with a
vertical flue about 1200mm long.
The boiler has been running fine, but lately it has been pooling water
underneath it every couple of days.
I have removed the cover from the boiler and traced the water to the
bottom of the flue, where the white flue pipe enters the boiler and
joins a grey pipe. At this join there appears to be water dripping
Below this join is a grey cylinder; I think this is the Condenser???
Is it likely that this will be full of water? Below the grey cylinder
is 2 vertical grey pipes, one of which is teed into with a black pipe
that goes to a white box and then to the condensate drain.
The two vertical grey pipes are capped at the bottom.end in a cap.
Does this problem mean there is a blockage in the drain?
Should this boiler have been installed with a vertical flue?
How can I drain this water out of the flue?
Reply to
Don't know which Bosch model you have, but mine has a condensate reservoir which at the bottom left which fills up and empties periodically via a syphon arrangement - the idea is so it doesn't drain with a continuous trickle which would make it likely to freeze during icy conditions.
I suspect yours just has a leaking joint in the condensate drain pipework.
Reply to
In article , Lobster writes:
Given how quickly the slightly acidic condensate can damage a boiler (the casing in particular), I did quite a thorough check on my Keston for any such leaks after having had one in a faulty flue part. I left a hosepipe trickling in to the flue exhaust terminal for about 30 minutes to check that it was draining away correctly with no water appearing where it shouldn't. I don't know if that's a safe test to do on your boiler without risk of damage, not knowing that boiler. One of the gas installers might comment, but I would suspect this should be safe on most condensing boilers as they have to handle condensate running back down the flue. (Make sure you don't feed it into the air intake though!) It might not test all the same condensate paths that are followed by condensate generated in the heat exchanger though (it does in the keston C25).
Reply to
Andrew Gabriel
I do sometimes run water in through the tapping point on W-B flues (or even pour in through the flue terminal) to test the condensate pipework. Never had any appearing anywhere inside the boiler but they are W-Bs, not Baxi Barcelonas :-)
Reply to
John Stumbles

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