F & E Tank Overflowing

[bennyd]

Hi,
I've seen a few threads about this, but not 100% sure on the answer for me. The F & E tank keeps overflowing when the hot water is on, its like a fast drip and then slows to a slow drip when its off. The water in the F & E is warm and the ball valve is working as it should. When the tank fills, the level is covering most of the ball and the valve is definitely closed. I assume this means it is filling from the pipe at the bottom?
The F & E has 3 pipes, one at the bottom which gets warm, one at the top which is the cold water (coming from mains supply as i cant see it connected to the cold water tank) and the pipe going over the top of the tank.

The F & E tank is about a foot or so lower than the cold water tank. I live in a town house, the boiler is in the kitchen on the middle floor, the hot water tank is in an airing cupboard on the top floor and cold water and F & E tank is is the loft.

I emptied the F & E tank down to about a third full where it looks like the level has been for years (a clear line around the tank) and it fills up (a rise of about 20cm) the next time the hot water is on if the pump is set to speed 2 and within a couple days if it is on speed 1 (we have the hot water come on twice a day). I thought i had fixed it by switching to the lower speed, but it was not to be.

The hot water coming out of the taps is not dirty so unsure if the coil in the tank is damaged. We had a new 3 way valve and pump fitted last December and things appeared fine until about 2 weeks ago.

We have not had the heating on recently so unsure if this would affect things.

Is there anything else (simple) i can try before calling in a heating engineer?

Thanks

 

[blup]

I think its called pumping over whereby your pump is in reverse flow or has not been placed correctly within the system. If its suddenly happened though maybe a boiler or pump fault.

Blup

 

[bennyd]

I have attached a couple images of the pipework around the pump.
The pipe marked with the red line is from the boiler (I assume)
The pipe marked with green is the into and out of the hot water tank
The pipe marked with yellow goes to the radiators
The pipe marked with blue goes up to the F & E tank and is the one that I think is filling it

The pump has an arrow pointing downwards so i think this is installed correctly. It was done by a heating engineer so i hope so! It was installed in the same place as the previous one which was done at the same time as a boiler replacement about 15 years ago (before we moved in).

I thought about pumping over which is why i reduced the pump speed.

There are no faults on the boiler, its a Baxi Solo 15 HE. Is there a way to easily see if there is a fault with either of these 2 parts?

 

[Dereekoo]

Try bending the arm of the ball cock downwards by a few inches, it may not stop the actual over pumping issue (if there is one?does any flow come out of the pipe going over the top of the tank when pump working?) but it may keep the top water level in the header tank at a level below the overflow pipe When everything is switched off and cold how far below the overflow pipe is the water level?

 

[denso13]

Normally a blockage in the pipework where the feed joins at the T piece (blue line). If a magnet is attracted to the area it will point to that.

And read my sig ⇩!

 

[bennyd]

Normally a blockage in the pipework where the feed joins at the T piece (blue line). If a magnet is attracted to the area it will point to that.

And read my sig ⇩!

Thanks. I'll check that later and let you know what happens....and i'll call it a cistern in future!

 

[bennyd]

Try bending the arm of the ball cock downwards by a few inches, it may not stop the actual over pumping issue (if there is one?does any flow come out of the pipe going over the top of the tank when pump working?) but it may keep the top water level in the header tank at a level below the overflow pipe When everything is switched off and cold how far below the overflow pipe is the water level?

I dont think any water comes out of the pipe going over the top of the tank cistern. I can try bending the arm a bit more, its been the same level for many years so i think its set at a good level, but worth a try.
At the level of the line i was talking about, its about 15-20cm below the overflow pipe. I am happy to empty it out further though.

 

[Johntheo5]

The CWST is higher than the F&E tank, if the HW cylinder coil is (pin) holed then the water will rise in the F&E tank.
Even if pump over through the vent is taking place with the HW/pump on then that should not cause the overflow as the water would just recirculate.

 

[HERTS P&D]

John, it's a cistern, not a tank!



Andy

 

[Johntheo5]

I've searched my attic and just can't find one of these, there is one in my batroom though.

 

[denso13]

Same thing, box with a lid and a ball valve/overflow. A cistern...

 

[Johntheo5]

 

[bernardgreen]

When the tank fills, the level is covering most of the ball

That might indicate that the washer in the ball valve is worn and needs replacing.

The deeper the ball is the greater the pressure that is exerted on the washer in the valve.

 

[Dereekoo]

Same thing, box with a lid and a ball valve/overflow. A cistern...

Header tank

 

[Dereekoo]

I dont think any water comes out of the pipe going over the top of the tank cistern. I can try bending the arm a bit more, its been the same level for many years so i think its set at a good level, but worth a try.

Perhaps the valve is not working as efficiently as it once was and the washer needs replacing?