Central Heating leak sealer

HouseBuyer77

Hi,

I am suspicious I have a small leak in my central heating radiator circuit somewhere (had the diverter/pressure release valve and expansion tank changed which definitely were leaking a lot and now aren't at all). I was considering adding some leak sealer though I do see warnings this can block up more than it should causing issues.

The boiler is an Ideal C80FF around 12/13 years old, I think leak sealer can only be a problem with newer condensing boilers due to their tiny pipes?

Any advice? Any recommendations on which one to use (seems to be sentinel v fernox)?

Dave_J_3

Hi,

Why do you thing there is a leak? Are you losing pressure?

Start with the basics, check all accessible connections, especially radiator valves, diverter valves if you have them etc

I would hold off putting any leak sealer into a system. Its much better to find the leak and resolve the issue otherwise a simple problem could become catastrophic.

HouseBuyer77

Well I'm possibly being paranoid.

There definitely was a leak which got sorted via a new expansion vessel and diverter valve. I had all the lockshields and TRVs replaced when that was done as well as they were all very old and delicate (at least one leaked quite a bit unless left fully open) which made trying to balance the system more or less impossible.

Since then the pressure has held fairly steady though recently it looks to be creeping down once again (it was sitting happily at 1.2 bar, then took a sudden dip to more like 1.1 and is potentially slowly edging down from there, the needle certainly went from slightly above the 1.1 line to below it). I have examined all visible pipework and looked at the radiators etc and can't see anything obvious.

Another issue is the circulation in the system seems poor. I'm currently running some system cleaner through in the hope it sorts it out. So I'm going to be draining down the system again in a few days to flush that out and thought it might be worth bunging some leak sealer in at the same time.

Can adding leak sealer cause major problems? What simple problem would become catastrophic if I did add it?

Le_Kirk

Are you sure you released all the air after refilling following your replacement of diverter valve etc? Are you looking at the gauge at the same temperature every time. The pressure will increase slightly as temperature increases.

HouseBuyer77

Are you sure you released all the air after refilling following your replacement of diverter valve etc? Are you looking at the gauge at the same temperature every time. The pressure will increase slightly as temperature increases.

Well it's hard to 100% sure, but I have been been careful to bleed everything and haven't been getting any extra air out. I've also been checking the system when it's cold. As I said above if there is a leak it appears to be very slow I may just be being paranoid!

unclebulgaria

HouseBuyer77 wrote: »

Well it's hard to 100% sure, but I have been been careful to bleed everything and haven't been getting any extra air out. I've also been checking the system when it's cold. As I said above if there is a leak it appears to be very slow I may just be being paranoid!

Have you treated the central heating system with inhibitor?
The reason I ask is that untreated systems can create air or sometimes hydrogen that, if one is fitted, can be released from central heating systems via the auto air relief valves or even manually from the radiators. This would appear as a pressure loss over time.

HouseBuyer77

The plumber who did the previous work did put inhibitor in.