F and E tank overflowing puzzle

Weird.

You say when the heating is off there is no overflow? It only overflows when running? So, fair enough, that suggests it ain't the ballcock that hasn't shut off fully 'cos that would be happening all the time.

But, if the issue was a holed coil, then this would surely be the same - it would also happen regardless of whether the heating was on or off?

So, perhaps the fact your F&E tank is overflowing cannot be pinpointed to either of these causes.

You say the water level in the F&E tank is higher than that in the CWS? How do you know? I mean, are you sure? The two tanks are completely different sizes, so how are you judging the levels in each?

Is the water level in the F&E tank pretty high - within a half-inch of the overflow outlet? If so, that's too high - it doesn't allow for room due to water expansion.

I guess - in theory - if the coil was holed, then the two levels should be the same when the system is left standing. I guess.

But, if you are sure they are not - that the F&E level is higher - then I wonder if what is actually happening is that, due to a partial blockage in your rad pipe system, whenever the pump turns on, water is partially forced up the feed pipe to the F&E tank, raising its level, and potentially dumping some out the overflow pipe. And then, when the the pump turns off, this level drops suddenly (sometimes you'll even get a slug of water shooting up the expansion pipe and dropping in to the tank, but the lower level will now trigger the ballcock to top up the tank - and the process is repeated every time the pump turns on.

Ok, that's a long shot, but can be easily checked by having an observer up there with as torch when someone else turns the system on and orf.

 

Add some really strong dye to your F+E tank run the system and then run the hot water and look for the dye if it's leaking I would guess it would leak both ways

 

Thanks for your thoughts, I think I do need to see what happens in the tank when heating switched on and off. As far as judging the levels goes, the 2 tanks are right next to each other and it is quite easy to see that the level in the F & E tank is higher. The level in the F & E tank has been up to the overflow each time I have checked it. I probably need to get the plumber in, it's got to the point though when I'm really trying to understand myself what's happening. Thanks again

 

Thanks for advice

 

Old Johnny here again.
There was YEARS & YEARS ago 50+ god I getting old. 82 years old last Friday LOl.
A coil mod to change a Direct cylinder into an Indirect one.
Cut 2 holes in the cylinder wall and feed this extra loop into them.
The seals and washers were cut at an angle and allowed them to be
fed INTO the inside of the cylinder on to the threaded connectors that were
about to be tightened on to the cylinder wall.
It worked well.
But its just maybe part of history now.
Its great to be able to remember these things though. LOL

Have a nice day.
Johnny M

 

Happy birthday

I remember these too. That's why I looked for replacement coils for leaking ones, but couldn't find one

I guess they reckon if the copper pipe has corroded that much, the whole cylinder cannot be far behind?

 

Hi
The reason your tank is overflowing, if, the tank is same level as cold water storage, and not the ball falve letting by is....
The clue in in the name of the tank! Feed and expansion!
When water gets hot it expands, the level of the water when cold, low level, will rise to high level when hot.

If the over flow level is too low in the tank the volume may not be enough to allow for the expansion.

This often happens when a thermal store cylinder is fitted, this type of cylinder increases the system volume, and often need a bigger expansion tank.

Hope that was clear to you?

Regards
Peter

 

Haven't looked on here for a while, I appreciate your comments and advice. Will discuss with plumber!

 

Hi, sorry for delay in acknowledging your advice, thank you for comments. I follow your reasoning, I guess it's because it hasn't been a problem before, I'm wondering what might have changed. Don't think I've any real alternative to getting plumber in to check it out properly, thanks again