slow leak under floor

[beeches1]

How effective are CH leak sealers?

Before I dash off to Toolstation, is it worth doing a flush first and then adding the sealer plus a new dose of inhibitor as well? There are cold spots on the system, particularly around a couple of old rads that went in about 20 years ago so I'd prefer to get the system flowing as well as possible, then do the remedial work.

Any leak is downstairs, no sepage anywhere upstairs or on the ceilings so I don't want to pull up all the carpets unless I have to and am hoping to get another 3-4 years out of the boiler before updating the whole thing. It's a Worcester Bosch combi, about 10-11 years old.

 

[Agile]

Have you checked the PRV vent?

Tony

 

[beeches1]

Re PRV, yes gas board replaced that on a call out this week. The system looses pressure overnight, if we top up to top of 'green' bar it's way back down below within 24 hours

 

[ianmcd]

what is the make and model of your boiler ?

 

[beeches1]

Worcester Bosch Greenstar R35

 

[ianmcd]

I know its a bit cold to do it this time of year but your boiler has two isolation valves below the boiler on the flow and return if you can do without the heating for say 24hrs if you pressurise the boiler then close these it will tell you if the leak is on the boiler or on the system pipework, be aware though that closing the iso valves then opening them again might cause them to leak

 

[beeches1]

Thanks, I'll try that. The speed that the pressure drops means that currently it goes through the green triangle and probably the same amount below it in about 24hours, therefore if I did it one morning before work then checked when we got home (abt 10 hours later) there would be at least a visible drop if that was it.

I'll leave it for a few days till the weather forecast is mild though!

 

[andytw]

Have you checked for water coming out of the PRV since it was replaced ?

 

[ianmcd]

it would be worthwhile to tie a small bag or attach a balloon or similar to the outlet of your PRV to see if any water gets in there this will rule out expansion problems

 

[beeches1]

ok, cheers, will do