Worcester 15SBi Boiler losing pressure with no visible leak

[Brambles99]

I have a worcester 15SBi boiler that keeps losing pressure with no obvious signs of a leak. I have checked every pipe in the system (Including those under the floorboards) and there appears to be no leaking water. The pressure drop occurs when the system is not in use and has been cold for a number of hours. Furthermore, when a section of the heating that feeds the conservatory in the house is isolated the problem doesnt occur. A friend who is a plumber has thoroughly checked the pipes in the conservatory and as mentioned earlier there are no signs of a leak. What are the possible causes of such a scenario? Another point worth noting is that the wall where the relief pressure water pipe empties outside the house shows signs of significant water discharge. However, at no point have I witnessed the pressure exceeding 3 bar and as stated earlier the pressure drop occurs when the system is off.

 

[lame plumber]

thats because the water cools and pressure then drops, call in an engineer who knows what he is about, yours obviously doesnt, as I am 98% sure of the problem without seeing your boiler fm what you have said!

 

[Killy Bing]

Likewise as lame. Post up in the "im looking for a plumber section" to get a competent heating engineer

 

[happyflyer]

Why is this so complex, you have just stated if you turn off the conservatory section it doesn't lose water, then leave the conservatory isolated for a week , if you don't need to top it up then its there somewhere, like the others say a good plumber should sort this in minutes, when you isolate the conservatory, I take it you close two valves a flow and a return and I take it there is pipe in the conservatory slab that you cannot get at, is this so???

The water discharge marks on the boiler safety vent on the wall may well be old marks, (when did you first notice these) there are temporary ways to test if water is coming from that without sitting there all day in a chair watching it, your plumber should have done this already so you can rule out this valve discharging. Clues, 4" nail, bucket, string, plastic bag, need I say more, do the conservatory thing first

These are simple tests that should have been carried by now, these are the obvious ones, your plumbers has not been much help so far, there are plumbers that don't know much and there are plumbers that know a lot.

Always confuses me why people down tell you where they live, they may be right next door to proper help, embarrassed when it's Kensington and can'y get a good plumber.:6:

BTW how do you know your safety valve blows off at 3 bar and not 2 bar or less???

 

[Ermintrude]

I agree. If u can't see leak and it's defo on isolated bit, get some leak sealer . If you ask ray stafford sure he can supply some.

 

[happyflyer]

Ermi,

Let him see if it is a leak first, its like Bletchley Park and the Enigma code cracking this.

And we have an extra hour to crack this one.:83:

 

[Dotty]

I agree. If u can't see leak and it's defo on isolated bit, get some leak sealer . If you ask ray stafford sure he can supply some.

Not unless the OP is trade Ray won't.

 

[happyflyer]

Likewise as lame. Post up in the "im looking for a plumber section" to get a competent heating engineer

Ermi,

The only proper leak sealer is a proper plumber and if the leak is under s concrete floor, re-route it , it's tough!!

 

[happyflyer]

Here we are flushing systems out to get them clean, banging on rad to get the crap out, adding chemicals to keep them clean, fitting mag
-cleaners too and then we go putting Gods knows what in to stop leaks, how bad a leak would this stuff cure, wonder if it says on the tin, in litres please!!!

What has plumbing come down to.

 

[Brambles99]

Thanks for the responses. I isolated the conservatory (Two valves - one on the inlet and one on the outlet) for over a month when the problem first occurred and when I did this the pressure in the boiler didnt drop during that time. When I reconnected it the pressure in the boiler remained steady for 6 days and then suddenly dropped to zero. Despite repressurising it kept depressurising over a number of hours each time. I once again isolated the conservatory and the problem stopped and the pressure remained steady for another 9 days. ALL the piping and connections in the conservatory have been checked as I can get underneath the floor there from a hatch. There is no section of the conservatory piping that hasn't been checked for a leak. It goes into the conservaory via holes made in an old air vent that must have been part of the original house before the conservatory was added.

I'll make sure the plumber undertakes a check of the pressure discharge pipe using the methods described above. If this is the problem how is the pressure release valve failing when the conservatory is connected but not when it isn't?