Boiler leaking water

Myser

If it's a pinhole leak, then with the sealer it should hold for some time.  Are you able to take some more closer photos of the area where you think the leak is coming from?

It may be worth a second opinion, but understand you don't want the expense if you intend to replace it in about a year.

stephenb1979

I can't really pinpoint exactly where it is coming from. I would need to remove the insulation jacket, and I'm not sure if it can then be remitted.
Is sealant to be added to the system or applied to the exterior to seal the hole?
Could it be a cracked boiler rather than a pinhole or would there be more water?

Myser

I woudn't recommend trying to remove the insulation as you won't be able to put it back.

Something like this - you'd add it to the header tank:

https://fernox.com/product/leak-sealer-f4-500ml/

If the insulation jacket remains damp after the boiler has been running for some time, then the leak may be more than just a pinhole.

What is the state of the water in the header tank?

stephenb1979

Looked at the header tank this evening.  Photo attached. Expecting the sealant to arrive tomorrow. I think I have to remove water from header tank and then add the bottle of sealant. Is it easy to drain water from the system to let the sealant into the system?

Myser

Difficult to tell the state of the water, are you able to take some out in a container?  Is there much debris at the bottom of the tank?

The drain-off point should be at a lower point in the house.  Perhaps outside or attached to a radiator.  It'll look something like this:

stephenb1979

I found this which may be the drain off point?  Not sure if its connected to radiator system though.  Is there a drain off point for water tank, and seperate one for radiators?
If this is it, do I need a special key, and should I also add inhibitor with the sealant?

stephenb1979

Type your comment

Myser

Yes, that will probably be the main drain off point for the central heating system.

You can use an adjustable spanner, pair of pliers or purchase a universal key if there is enough clearance below: https://www.toolstation.com/service-cabinet-key/p18822 

You will need to add inhibitor but if you find lots of debris and the water is very dirty in the header tank, it may be a good opportunity to drain down the whole system, clean the header tank and refill.