Boiler leak?

[thefurz]

Any ideas or suggestions are gratefully received!

We have a Keston c36 combi boiler which seems to be losing water fairly rapidly. Usually 20 minutes after the heating has gone off an E37 error message flashes which I am told means the water pressure has dropped.

It was serviced last week and the engineer said there was nothing wrong with the boiler but to get a plumber to look at the leak. We have identified the external overflow pipe but water doesn't seem to be coming out there.

There are two odd things. The first is that the water pressure seems fine when the heating is on. It is only when it is switched off that we get the error message.

The second is that we can hear a dripping noise in the boiler cupboard...but can't see the water! As the picture shows there is a piece of wood attached to the back wall but it is open at the bottom meaning any water dripping behind the wood should be visible on the floor of the cupboard.

The wall in the cupboard is the external wall. Could there be 2 external overflow pipes? Could the leak be behind the boiler cover? I can hear water dripping but not see it.

Thanks
View media item 70645 View media item 70646 View media item 70647 [/img]

 

[dcawkwell]

The dripping is just the condensate I would say.

Pressurise the system up to 2 bar and leaving it completely switched off all day. Does the pressure drop?

Next test is to pressurise the system up to 2 bar again
then isolate the boiler flow and return pipes with the boiler valve and
leave it switched off all day. Does the pressure drop?

If the boiler keeps pressure you have a leaking in the central heating my guess would be the underfloor.

 

[thefurz]

The dripping is just the condensate I would say.

Pressurise the system up to 2 bar and leaving it completely switched off all day. Does the pressure drop?

Next test is to pressurise the system up to 2 bar again
then isolate the boiler flow and return pipes with the boiler valve and
leave it switched off all day. Does the pressure drop?

If the boiler keeps pressure you have a leaking in the central heating my guess would be the underfloor.

Thanks for the response. I have just spent an hour or so searching every joint and checking all the pipes and the floor for a sign of a leak and didn't find one. I then put my finger on the white pipe that comes out in the centre of the boiler and felt a strong 'pulse' that coincided with the drip.

My manual said this was the condensate pipe so I am glad to see you think it may also be this!

Where will I find the boiler valve?
Thanks again.

 

[dcawkwell]

The dripping is just the condensate I would say.

Pressurise the system up to 2 bar and leaving it completely switched off all day. Does the pressure drop?

Next test is to pressurise the system up to 2 bar again
then isolate the boiler flow and return pipes with the boiler valve and
leave it switched off all day. Does the pressure drop?

If the boiler keeps pressure you have a leaking in the central heating my guess would be the underfloor.

Thanks for the response. I have just spent an hour or so searching every joint and checking all the pipes and the floor for a sign of a leak and didn't find one. I then put my finger on the white pipe that comes out in the centre of the boiler and felt a strong 'pulse' that coincided with the drip.

My manual said this was the condensate pipe so I am glad to see you think it may also be this!

Where will I find the boiler valve?
Thanks again.

You should find a valves on the boiler flow and return pipes at the bottom of the boiler. Both 22mm pipes. There will both be hot when the central heating is on.

 

[gigz]

Does the drip still happen when the boilers been switched off for a while ?

 

[thefurz]

Does the drip still happen when the boilers been switched off for a while ?

Not really no. It drips when we top up the water and when the boiler runs.

In the last day or so we have noticed water leaking from around the white condensate pipe. We have been in touch with a plumber who suggested it may be a cracked heat exchanger....?