Combi Boiler vent Stains On Wall
Stuart
outside wall to the back of the flats . Earlier today I noticed that
directly below the vent there was a reddish brown wet stain runing down
the wall to the ground . It starts immediately below the vent . I have
never noticed this before so it must be recent .
Is it possible ( and in what circumstances) for water to come through this
vent . I dont know how combi boilers work but do they need to be drained
-presumably there might be occasions when the CH system has to be drained
but again presumably,there would be an outlet for this water into an
existing drain . Is it possible that someone has drained the system and
put the draining hose out this vent to get rid of the water ??-cant see
how THAT would be possible as the boiler will be sealed to the vent -won't
it ?? .
Stuart
--
"YESTERDAY is history,TOMORROW is a mystery,TODAY is a gift
That is why it is called the present "
IMM
"Stuart" <stu...@xpozureSPAMTRAP4u.fsnet.co.uk> wrote in message
news:vher705shbmik9qdo...@4ax.com...
> My neighbour in the flat below has a combi boiler vented through an
> outside wall to the back of the flats . Earlier today I noticed that
> directly below the vent there was a reddish brown wet stain runing down
> the wall to the ground . It starts immediately below the vent . I have
> never noticed this before so it must be recent .
> Is it possible ( and in what circumstances) for water to come through this
> vent . I dont know how combi boilers work but do they need to be drained
> -presumably there might be occasions when the CH system has to be drained
> but again presumably,there would be an outlet for this water into an
> existing drain . Is it possible that someone has drained the system and
> put the draining hose out this vent to get rid of the water ??-cant see
> how THAT would be possible as the boiler will be sealed to the vent -won't
> it ?? .
> Stuart
Check if it is coming from the blow-off pipe, which is normally terminated
below the flue to outside. If the pressure gets too high in the system the
safety relief valve opens. The reddish brown is probably the colour of the
water in the system. A fitter could have opened the relief valve to release
pressure. Check this out.
The blow-off pipes should be terminated a few inches from the outside floor
level, with an elbow facing the wall. If it blows then it hits the wall at
the bottom. If it is terminated at high level it could spay boiling water
on someone beneath.
If it is the blow-off pipe then get him to run it down the wall. Also get
them to clean the wall.
John Rumm
> Is it possible ( and in what circumstances) for water to come through this
> vent . I dont know how combi boilers work but do they need to be drained
If it is a condensing boiler (many recently installed high efficiency
boilers will be) then you would expect allot of water vapour to come out
of the flue. You will normally see this as a quite visible plume of steam.
When the boiler is installed the flue should be installed at a slight
angle through the wall - such that it runs "uphill" from the boiler (a
slope of one to two degrees is usually enough). Hence any moisture that
condenses in the flue before it gets outside should run back down the
inside of the flue and into the boiler.
If its is a condensing boiler, and, the flue looks like it is horizontal
(or worse sloping down), then that could be the problem - although it is
probably unlikely to be reddish brown itself you may find it is
discolouring the wall due to its slight acidity.
--
Cheers,
John.
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