Heating loses all pressure over 20 minutes

[KatieJ]

Hi, we have an oil central heating system with a Worcester boiler. Our radiators were not getting very hot today and on checking the pressure gauge, it was on 0. I topped it up to 1.5 bar and over about 20 minutes it again went down to 0. Ive topped it up several times but it just keeps losing pressure. There is no air in any of the radiators and no leaks that we can see. There is no water coming out of the pipe outside. Anyone know what the issue could be? Thanks for reading.

 

[ShaunCorbs]

You have a leak or it’s running down the condense pipe have you checked that ?

 

[KatieJ]

You have a leak or it’s running down the condense pipe have you checked that ?

Thanks so much for your reply. We have checked all the pipework and radiators and can see no leaks. The condense pipe goes into the soil pipe behind the utility cupboards so not easily accessible but I think that must be where it is going. There is no water under any of the units or around the boiler. What would be leaking for it to discharge into the condense pipe?

 

[ShaunCorbs]

Main heat exchanger

Can you disconnect the condense to see if it’s running / dripping when your filling up etc ?

If not it’s under / in a floor somewhere

 

[KatieJ]

Main heat exchanger

Can you disconnect the condense to see if it’s running / dripping when your filling up etc ?

If not it’s under / in a floor somewhere

Thanks, it looks like the main heat exchanger is leaking.....its 16 years old so time for a new boiler I think! Thanks so much for your help.