Using sealant to fix leak in central heating system.

We have a leak in our central heating system.

There is staining on the kitchen ceiling suggesting the problem is the pipework into the bathroom radiator. (There is no staining on the floor around the radiator, suggesting it's the pipework under the floor.)

We appear to have three options:

1. Try putting sealant into the system to see if that solves the problem.
2. Take up bathroom tiles and floor boards around the radiator.
3. Access the pipework via the kitchen ceiling.

When the system is pressurized, it loses pressure in a couple of hours. Is this too quick to make using sealant worthwhile.

Also, to go the sealant route, I was quoted €680. Seems excessive.

Any feedback appreciated.

Thanks.

D.

I am not a heating engineer. I do think you might need to provide a few more details for an engineer to weigh in.

How old are the pipes and radiators? What type of metal are the pipes? How big is your house and CH pump?

Apparently old gun-barrel pipes have about 30 years in them, more if you're lucky. Pouring sealant in will only be a temporary fix if you have these pipes.

Thanks.

System is 18 years old. All hidden pipe work is plastic. Exposed pipes - just a few centimetres each - are copper.

House is three bed semi.

My instinct is to try the sealant route first before cutting into floors and/or ceilings.

Thanks again.

D.

Dinarius said:

When the system is pressurized, it loses pressure in a couple of hours. Is this too quick to make using sealant worthwhile.

Click to expand...

This would suggest to me that sealant would not be successful. (presuming by pressure drops you mean something like from 1.5 to 0.5 bar in 2 hours).

Dinarius said:

2. Take up bathroom tiles and floor boards around the radiator.
3. Access the pipework via the kitchen ceiling.

Click to expand...

There is no guarantee that the location of the staining underneath corresponds with the location of the leak above (water can travel for quite a distance on horizontal elements before dropping onto the ceiling plasterboard below).
Did the ceiling staining and the ch pressure drop occur simultaneously? (You might want to consider that the ceiling staining may be from another source)
If something needs to be opened up, I would open up the ceiling below.

Dinarius said:

Exposed pipes - just a few centimetres each - are copper.

Click to expand...

This means that there is a coupling joint immediately below the floor at each radiator connection.

The leak is unlikely to be along the plastic pipe unless a mouse has gnawed it.

If there is any small gap at the radiator pipe holes, you could try pushing a strip of cloth attached to a piece of wire down each hole. It should get damp if any of the couplers are leaking.

Thanks.

Attached is what the wall looks like after the leak. The stain at the top is just below the bathroom radiator. Though, I guess it could have crossed the ceiling to that point. But, there's no radiator over there, only the pipework from the boiler, which is on the opposite wall of the kitchen. So, bathroom radiator is the most likely culprit.

D.

Patching a hole in a plasterboard ceiling is a very trivial exercise for any painter or even DIYer. I’d be cutting a fist size hole (carefully so no damage is done to pipes above) and shine a torch in there to take a look, you can always make a couple more holes. A plumber will happily do this either and also be able to fix the leak. This needs to be done ASAP though because plasterboard getting wet repeatedly like that is liable to fail altogether and come crashing down.

Agree with Zenith, the plasterboard likely needs replacing anyways so no harm cutting a few inspection holes. If you can see the pipes spray some soapy water all around the pipes with the heat on, using a good torch you may be able to see the leak bubbling.

Agreed. Fixing a hole in the ceiling is much easier than retiling the bathroom floor.