At my wits end

[Derrick Brown]

I have a leak somewhere on my heating

It’s a combo system, the system has been in over 20 years with no problems

New boiler 4 years ago

Something has developed a leak

I have two radiators in the conservatory whose pipes are under a screed floor, I have isolated them

All the other pipes are exposed, downstairs fed by drops

There is no stains on the ceiling, nor under the floor boards upstairs, only pipe work I can’t check is in the bathroom, that is tiled, but it’s above the kitchen, no stains or water marks on the ceiling

I was going to try a leak sealer I have no used one before, I have had MB 40 in the system before and after the new boiler was fitted

I have had Valiant out to check the boiler, they said it was fine, no problems with it

So where do I go from here?

 

[gas112]

have you isolated just the boiler to make sure its not that leaking out through the condense

 

[Derrick Brown]

Yes, Vailiant did that
It’s got to the point I have to top it up every day
Nothing from the safety valve or overflow

 

[gas112]

how long did they isolate it for ?

 

[Derrick Brown]

Valiant isolated the boiler for 30 minutes, dropped .2 bar

So I am assuming it’s on the radiator side

Checked all the drain valves aren’t letting by

I bring it up to 1 bar, the hearing is on for 1 hour in the morning and 4 hours in the evening, by the morning the system says 0 bar

no sign of water though, anywhere

 

[Ian H]

Doesn’t a faulty expansion vessel cause the pressure to drop?

 

[terryplumb]

Valiant isolated the boiler for 30 minutes, dropped .2 bar

Hardly conclusive proof that the boiler isn't losing pressure is it ?

 

[Derrick Brown]

It does but that was checked by Vailiant,

the water must be going somewhere, but I’ll be buggered if I can find it

 

[Ihavenojob]

If they isolated the boiler, and it dropped .2 bar in 30 minutes it is most likely that the heat exchanger is leaking and the water is dripping out of the condense pipe, which I doubt you would see. Or did they isolate the boiler for 30 minutes and then the pressure was stable, but dropped when they opened the valves again ?

 

[Derrick Brown]

They isolated the boiler from the radiators, 30 minutes, then open up the valves, it didn’t drop from the boiler, just when they opened the pipe work and radiators

So my thinking is it’s on the heating side (that is what they said as well, they checked heat exchanger and pressure vessel)

I put a bag over the condense pipe to see if it was that leaking, the same as the safety valve, so I am thinking it’s not the boiler

 

[gas112]

Valiant isolated the boiler for 30 minutes, dropped .2 bar

So I am assuming it’s on the radiator side

Checked all the drain valves aren’t letting by

I bring it up to 1 bar, the hearing is on for 1 hour in the morning and 4 hours in the evening, by the morning the system says 0 bar

no sign of water though, anywhere

30 mins is a complete waste of time for small leak and will show nothing needs to be left minimum over night at this time of year

 

[Derrick Brown]

Okay, when the heating goes off over night, I’ll isolate the boiler from the rads, pump it up to 2 bar and check in the morning

But as this has been going on over 2 weeks it should show somewhere

Not showing any water in the pipe work from the safety valve or condense line (bags are empty)

Not wet floors or carpets

is it worth putting in this leak sealer, I have nothing to lose

 

[endecotp]

is it worth putting in this leak sealer, I have nothing to lose

I’m not an expert, but it has been suggested on here that that stuff will gunk up the boiler and pump and it might invalidate the boiler warranty.

 

[Derrick Brown]

Well I can’t find any water anywhere

I’ll be using 500 mil bottle, there is inhibitor in it all ready 2 litre MB40

2 rads in the conservatory completely isolated

Maybe it will work, I’ll ask Valiant what they say

 

[terryplumb]

How have you isolated ,completely, the 2 conservatory rads ?
Turning off the rads valves will not isolate the pipework that goes to them from the rest of the system.
And leak sealer can do more harm than good.