Ongoing Overflow Issue

[Mark Rigby]

Hello,

I am seeking help on an ongoing overflow issue I have. I'll give as much information as I can based on my limited knowledge of systems. Our system has the hot water cylinder in the airing cupboard, and is fed by a large water storage/feeder tank above it. Our cold water is fed directly from the mains water supply although we do have a smaller water storage tank alongside the large one but I'm not sure what this does- and the leak is not coming from here.

The overflow pipe from the hot water feeder tank starts leaking every year when we start to use the central heating; everyone constantly tells me that this is the ballcock valve which I disagree with as we have no issues from March-September when we don't use the central heating system. The common trigger here is when we start to use the central heating with regularity. Is there a way that the hot water cylinder can be 'backflowing' the storage tank causing this to overflow? The water that leaks is cold but it definitely comes out of the white plastic overflow pipe which feeds out of the larger tank that provides our hot water.

I'm at a bit of a loss, as we have changed the ballcock valve on many occasions due to advice we've been given but I am absolutely convinced this is not the cause.

Thanks in advance,

Mark

 

[ShaunCorbs]

Is there a dripp from the pipe that goes above your plastic tank and drops back into said tank

Your other little one is for the heating (to fill and vent)

And any chance of a few pics of the tanks and airing cupboard

 

[Mark Rigby]

Hello, I have attached the images for you.

There is no drip back into the feeder tank; the top of it is covered.

Rgds,

Mark

 

[Jones82]

I'd check a few things;

Is the overflow hole in the tank too low, does it allow for expansion of the system when its is heated.

Is the cylinder thermostat faulty, causing the hot water to be excessively hot.

Is the 2 port or 3 port valve working correctly, does it shut off after the hot water demand is satisfied.

My guess would be the system is excessively hot, it expands, the water level rises and flows out of the possibly low overflow connection in the tank.

One rare possibility is back flow across the hot and cold pipes causing the tank to fill from its cold water outlet.

 

[Best]

Is the water level in the large storage tank normally very close to bottom of overflow outlet?
Also, - Is the vent pipe (that comes from the top of copper cylinder and up into loft) a lot higher above the cold storage tank, before it drops down to well above water level?