hot water leaking into overflow/header tank

[mik118811]

Hi All,

I am looking for a solution to a problem i have had with my heating system for a long time.

I have an old back boiler downstairs with two pipes leading up from it. i have a cylinder tank in a bedroom and then a header/overflow tank and a large cold water tank in the loft. by the cylinder i have the pump which feeds onto the tank and onto another pipe which overflows into the header tank also to a pipe which is the feed from the header tank and a pipe which goes downwards which i presume is the feed to the boiler.
I have been reading many articles about the problem i have which is water going into the header tank via the feed not the overflow. i have changed the ball cock valve as i presumed that was the problem originally but that didnt affect it. i drained the system the other evening and left it well below the overflow pipe onto our roof the following morning after no hot water or heating had been on it was overflowing. ive read it could be a range of things from pipework to the hot water cylinder coil. is there a way to find what the problem is without having to get a plumber in charging for a call out, i am a competent diy plumber so would rather do it myself if possible or to atleast find what the fault is before calling a plumber out to fix it if it is not within my skill range.

Any help would be much appreciated.

Many thanks in advance for any help offered

 

[tamz]

Take a picture of it if you can

 

[mik118811]

which bit would you like a picture of?

 

[tamz]

The pipes at the cylinder cupboard

 

[mik118811]

here is the pics of where the pipes go up and also where the pipes go down from the pump

 

[helpsy]

Looks like the feed/vent is wrong.
If water level dropping and ball valve topping up CWSC and overflowing in F&E this could indicated coil problem.

 

[mik118811]

i have been told the feed and vent pipe are incorrect sizes and incorrectly positioned, could this really be the main cause of water to back up the feed pipe though? the header tank gets very hot water in it which causes it to overflow but what could cause it to overflow over night when nothing is turned on? it doesnt seem logical for it to be overflowing constantly

 

[Deleted member 7121]

Check to see if there is a hole in the coil on the cylinder ( drain heating and disconnect flow and return at cylinder to check). if this is the case cold water tank pressure will enter hole and fill F and E tank

 

[mik118811]

will there be a clear visible sign that the coil is damaged once the tank is disconnected? i didnt mention that this problem has been going on for 2 years and only now it seems to be getting worse and worse as it began with just a drip now it is a constant trickle of water out of the overflow pipe, would the coil have failed completely in this time causing it to get worse?

 

[helpsy]

i have been told the feed and vent pipe are incorrect sizes and incorrectly positioned, could this really be the main cause of water to back up the feed pipe though? the header tank gets very hot water in it which causes it to overflow but what could cause it to overflow over night when nothing is turned on? it doesnt seem logical for it to be overflowing constantly

The water level in the CWSC is higher than the water level in the F&E if cisterns both fitted on same level, so if the coil is holed the water will come in from the CWSC through the cylinder and throughthe holed coil and up through the F&E(U tube effect) to the same level as the CWSC water, thus overflowing.Cold feed should be 15mm min and vent 22mm.Cold feed should be positioned between the pump and vent pipe with the cold feed/vent within 150mm of each other.Should also have an automatic bypass.