Central heating System Over flow.

[Roger29]

Hi , I have a 10 radiator system with header tank and powered by an Ideal standard floor standing boiler, my problem is that for a few weeks I have noticed my overflow running at certain times when the boiler has been operating and after looking in the loft I notice that the fill pipe at times is warm , I am guessing that the boiler is feeding back into the header tank and then over flowing has any one a sugestion. Roger

 

[Bahco]

Check water level when cold which should be 4 ins high first.

 

[rebuke]

If it's only overflowing when the boilers on, my guess is that the level when cold is too high, so when the water expands slightly when it heats up (as it's meant to), it's pushing the level just too high and going out your overflow.

As has already been said - check the level when cold, it might be your ballcock valve needs adjusting (you normally either just bend them, or sometimes you can move the actual float part up or down with a screw). Also check that the float hasn't got water in it, as sometimes they develop a hole - if this is the case, get a new one (should cost under a quid, as you can just replace the float part)...

A couple of other possibilities that come to mind are:
If you have a hot water cylinder, the coil may have a hole in it, causing the supply that is feeding the cylinder to force it's way back up through the heating pipes into your expansion tank (unlikely though as this would happen all the time, not just when your boiler is operating)
You might have a blockage in a pipe somewhere which is causing your pump to force water through the expansion pipe (do you have any cold radiators etc?)

 

[ChrisR]

Do you mean overflowing, ie outside - or pumping-over? See Faq on that.

 

[Roger29]

Check water level when cold which should be 4 ins high first.

Thanks for that I will check, well done for packing in smoking however I did some 6 years ago but still fancy one ever now and again.

 

[Roger29]

If it's only overflowing when the boilers on, my guess is that the level when cold is too high, so when the water expands slightly when it heats up (as it's meant to), it's pushing the level just too high and going out your overflow.

As has already been said - check the level when cold, it might be your ballcock valve needs adjusting (you normally either just bend them, or sometimes you can move the actual float part up or down with a screw). Also check that the float hasn't got water in it, as sometimes they develop a hole - if this is the case, get a new one (should cost under a quid, as you can just replace the float part)...

A couple of other possibilities that come to mind are:
If you have a hot water cylinder, the coil may have a hole in it, causing the supply that is feeding the cylinder to force it's way back up through the heating pipes into your expansion tank (unlikely though as this would happen all the time, not just when your boiler is operating)
You might have a blockage in a pipe somewhere which is causing your pump to force water through the expansion pipe (do you have any cold radiators etc?)

Thanks also and I will check the level and other bits.

 

[Roger29]

Do you mean overflowing, ie outside - or pumping-over? See Faq on that.

Overflowing out side but only at certain times when the boiler is on.

 

[Roger29]

Check water level when cold which should be 4 ins high first.

Hi bahco, when you say 4 in at what point.