Central Heating causing drain to overflow Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[nrg1977]

Hello,

The drain in my back garden was overfilling with hot water at the weekend and I believe this was happened by my Central Heating being on - turning my heating off eventually stopped this overflow.

Any ideas what could be causing this and if it would be a big job to fix - just want a heads up before the Plumber comes round.

I have a combi boiler.

Cheers

[htg engineer]

Check the pressure, it may be too high, set to between 1.0 and 1.5 bar.
If the pressure is rising when the CH is on then the expansion vessel is at fault.

htg

[nrg1977]

Thanks htg however pressure was fine.

Incidentally I switched my heating back on last night to test this. Fully expected drain to overflow again however it didnt happen. Heating was on and all radiators working, everything seems fine.

Should I still be concerned even though the problem looks sorted now?

Thanks again

[htg engineer]

Just keep an eye on the pressure over the next few days, it may be rising gradually (could be a hole plate heat-ex etc).

The boiler is doing as it should - if the pressure rises too much the water is discharged to outside - nothing to worry about, but it is worth keeping an eye on the pressure, as if the same happens next week or next month you still wont have any idea what is causing it.


htg

[nrg1977]

Great, thanks for the advice. I will certainly keep an eye on this pressure.

Thanks again!