Central heating pipe leaking internally....or not?

[Skyhigh]

We've been in the house 3 years, its only 7 years old and I've always known about this issue.

When the heating is on, there's a "tapping" noise that comes from the inside of a wall near a radiator (downstairs, next to a bay window).
Its not the radiator.

Previously, I've assumed it probably was just the sound of a pipe expanding slightly.

But now I'm wondering if its actually a small pipe leak.
Especially as the CH system seems to need bleeding more than other systems we've had in other houses...

The pipe is completely inaccessible, without ripping the wall apart.

I'm wondering about putting some internal leak sealer through the system to see if it 'goes away'.

Any suggestions?

There's no noise when the CH system is off...only when its running.


I'm not bothered about the circulating pump too much as its on its way out - and I'm going to run some cleaner through the system soon, fit a new pump and stick some inhibitor in.

 

[Whitespirit66]

If it was a leak it would be more likely that your pressure would keep dropping. Is it stable or not? Your first guess of expansion is more likely.

A system cleaner and correct inhibitor concentration will help with the excessive bleeding.

 

[Skyhigh]

Pressure - no idea. There's no where on the boiler or the heating tank/system that tells me the pressure in the system... so I can't monitor it.

For the £4 it costs from Wickes, would it be a bad move to put some sealant into the system anyhow?

(bearing in mind I'm going to put some cleaner in after about 4 weeks, let that run through for a while, flush it, drain it and then replace the pump?)

Can internal sealant have any side-effects?


Cheers,

 

[cantaloup63]

Is the house outside its guarantee period then?

 

[45yearsagasman]

Prove the existence of a leak first. I would not add leak sealer if not required.
If there was a leak you would have noticed damp patches surely.
Clean the system and correctly dose with inhibitor.

 

[Skyhigh]

Its outside its NHBC cover that would include the internal/central heating parts :-/

There are no wet-patches on the wall, or on the floor. But it's a fairly slow 'ticking' sound (maybe once every 5 seconds).

I was wondering that if its a slow-drip that only runs when the heating is on, then it might not 'show' easily. Especially as we don't often have the heating on for hours on end (and hour here and there).