Oil Central Heating - Slow Drip From Overflow in Attic

D_M_A

Hi all - was hoping for some suggestions on what the issue might be.

We have an oil fired central heating system with back boiler. House is a 2 storey semi-d with converted attic (radiator in attic never properly functioned but not the topic of this thread). The overflow from the heating system storage tank located in the attic has a slow but constant drip coming from it out into the back garden. It seems to get worse when the heating is turned on, to almost a steady drip. This hasn't always been the case so I'm wondering what has changed to cause this.

I have attached some photos of the storage tank in the attic. The ballcock and water inlet seem to be working fine, but as you can see the water level is right on the level of the overflow pipe.

Any suggestions on what the issue is here and how it might be fixed? Any help is much appreciated.

Cheers

Lenar3556

Ball cock is allowing tank to fill too high - needs to be replaced.

carveone

Either that or the fill valve isn't completely closing off, causing the tank to very slowly fill.

If the heat is on, I suppose the water expansion would raise the level a bit more, causing a bigger drip. For a short while anyway.

You could bend it down a bit and see if it helps. If not, might need a new valve...

Jim_Hodge

It doesn't look like it will take another bend without breaking. Get a new ball cock fitted.

carveone

https://www.boards.ie/discussion/comment/120982981#Comment_120982981

Yeah, I take it back 😁

D_M_A

Thanks for all the suggestions.

I have emptied out some of the water to lower the level in the tank and the inlet valve / ballcock has remained off/closed, suggesting that something else is raising the level and not the inlet/ballcock? Is this the only feed into the system? When at the lower level I can press down on the ballcock and the inlet valve will activate but it seems that the water level, if managed by the ballcock, is a lot lower than where it is currently at.

John.G

Presume this is the F&E tank for the boiler and the coil heats water in a cylinder?, is the cylinder vented or unvented?, if vented you will have another bigger cold water storage tank, CWST, whose water level would need to be higher the F&E tank level to cause the level to rise in the F&E tank if the coil is pinholed, if the cylinder is unvented, supplied from either a pump or the mains then this pressure will cause the level to rise in the F&E tank if the coil is pinholed.

Lenar3556

Other possibilities are much less likely than an issue with the ball cock. It’s old - I would change it first.

D_M_A

https://www.boards.ie/discussion/comment/120986513#Comment_120986513

https://www.boards.ie/discussion/comment/120986767#Comment_120986767

Thanks John, you're presumptions are correct - this is the tank for the oil boiler heating system with a separate CWST. The cylinder is heated from an immersion coil and is vented. I've checked the water level and the F&E tank sits above the CWST so the water level in the CWST is not higher.

Thanks Lenar. I'll have a look at replacing the ballcock although it seems to be working fine.

John.G

Yes, the ballcock assy is your first port of call, the F&E tank has all the hallmarks of pumping over through the vent when the boiler is on but this in itself will not cause overflow. A electric immersion with a failed thermostat can cause recirculation of very hot water in the CWST but can't see it affecting the F&E tank level.

Wearb

Anything new on the system, like a circulating pump, boiler, valves, radiators etc.

D_M_A

https://www.boards.ie/discussion/comment/120987509#Comment_120987509

Nothing new added that wasn't there previously, some elements (circ. pump and 1 or 2 radiators) may have been replaced alright. In the case of the radiators, the replacement was larger in at least one instance, with the addition of a TRV which wouldn't have been there previously.

Lenar3556

Circulation pump might be turned up a little high also. Some of the new modulating pumps are more powerful than the old pump they were replacing.