Condensation on my water & header tank

[Teggs]

Hi guys,

I wonder if you'd be able to offer me some advice?

I've noticed that there is a lot of condensation on both my water tank and header tank. Both are situated in a cupboard (it's an old Victorian house) in the attic of the property. Recently it has got so bad that I've noticed mould on the internal walls of the cupboard.

I've noticed that hot water discharges from the vent pipe into the header tank (and not the water tank) when the programmer is set to either hot water or hot water and central heating. I've so far not noticed the discharge into the header tank when the programmer is set to central heating only.

I've opened the doors to the cupboard to see if this solves the problem but it doesn't seem to have had any major effect on the problem.

I tried turning down the cylinder stat but this hasn't stopped the condensation occurring. Can any of you offer any more advice as to why this may suddenly have started to occur?

 

[brumylad]

have you made an changes to the system (new pump for example). could be a blockage of the primary circuit (the coil inside the copper cylinder), it might also bhe a blocked cold feed pipe. small diameter pipe dropping from the header tank to join up with the large diameter central heating pipes. The blockage is often at this junction, use a magnet to detect iron sludge inside the copper pipe.

 

[Bahco]

Introduce some air flow to ventilate your cupboard. Roof vents allow air in and will temper mould growth

 

[felix]

Ventilation is not the answer. Water should definitely NOT be pouring out of your vent pipe. Quite apart from the damp problem, this is continually aerating the water in your heating system and speeding its corrosion.

There are two pipes leading from your header tank into the system: the vent and the feed (aka expansion) pipe. In a fully pumped system these must join the system very close together. If they are separated, maybe one on each side of the cylinder heating coil, there will be a pressure differential and trouble. The last time I had a new cylinder put in, an otherwise competent plumber did exactly what I've just described. Result - every so often a bit of water slopped out of the vent pipe.

 

[Bahco]

I've noticed mould on the internal walls of the cupboard.

Ventilation will help control the mould.

As Felix says, the plumbing should be looked at. Any water not evaporated has to go somewhere

 

[Teggs]

Thanks for the response guys, the problem seems to have started a month or two ago, prior to that everything seemed fine. It therefore wouldn't have anything to do with the distance between the feed and vent pipe would it?

I'll dig out a magnet and check for iron deposits within the pipes, how can this be remedied if this is the case?

Terry

 

[felix]

If the vent and feed pipes are at opposite ends of the cylinder coil then a build up of sludge in the coil will increase the pressure drop forcing water ever higher up the vent pipe. At some point it will come over the top!

You can do a few things about this, listed in increasing order of merit - and difficulty:

a) Raise the vent pipe higher above the tank.

b) Clean out the coil.

c) Replumb the feed to the top of the coil alongside the vent.