Central heating pressure loss

[Nik01029]

Hi
I have a ideal logic 30kw system boiler runnong central heating and underfloor heating and an invented tank.
The boiler has always lost pressure to a degree but now it's worse than ever.
I've fitted isolators downstairs so I can turn that off and it still loses pressure. With the UFH isolated it still loses pressure. I have checked 90% of the pipework and fittings upstairs and I can't see a leak. All rad valves etc. I have pressurised to 2 bar and turned boiler off no leaks.
Left an aerosol lid under the prv pipe and it's bone dry.
It was losing a small amount then recently 0.2 bar a day. Now about 0.5 a day. It seems to lose more pressure when the ufh is on but I think k that's just because it stays on for longer periods.
Last week I put 2 bar in and isolated boiler,waited several hours for condensate to dry up then left an aerosol id under the condensate drain.
It filled the lid to approx 30mm deep overnight.
I feel it's the heat exchanger, and I'm looking at a new boiler because I have run out of ideas....
Any help would be great!!!!

 

[townfanjon]

I gather its out of warrenty, if so , you can just get the heat ex changed . It also might be worth talking to ideal to do a “fixed price repair”

 

[Nik01029]

It's well out of Warranty, I tried calling a couple of places and they're out of stock, I'm sure I read somewhere that's they're obsolete!!!

 

[ShaunCorbs]

Ideal heat exchanger nope they haven't stopped making them

Phone ideal up and ask them how much for a replacement I'm sure they have a fixed price repair

 

[Scott_D]

Has it got extra an expansion vessel or just the 8l internal?

 

[jtsplumbing]

Having same problem from one I installed in 09 just keeps losing pressure and no explanation of where its going, Ideal Tec tell me its main heat Ex , price of part + labour to replace don't think they cover this on fixed price repair, find out today what cost of part is, may be more cost effective to replace boiler

 

[Nik01029]

It only has the internal expansion tank, but the prv is bone dry....

 

[Nik01029]

I got a price for a vailant 30kw I might go for That but I'm half expecting it to still lose a bit of pressue when it's done!!!
At least I'll know where to look!

 

[Scott_D]

Why not get someone to check the heat exchanger before fitting a new boiler?
Should be pretty obvious if it's gone

 

[jtsplumbing]

Why not get someone to check the heat exchanger before fitting a new boiler?
Should be pretty obvious if it's gone

Interesting pice of video on YouTube showing one leaking,

 

[Nik01029]

Forgive me if I'm missing something but I don't see what somebody else is going to check on the heat exchanger that I haven't already done?
It seems worse at some times, last night only lost about .3 bar and today it's lost about 1 bar.
Still no marks in the ceiling and I've 're checked some of the connections

 

[townfanjon]

Forgive me if I'm missing something but I don't see what somebody else is going to check on the heat exchanger that I haven't already done?
It seems worse at some times, last night only lost about .3 bar and today it's lost about 1 bar.
Still no marks in the ceiling and I've 're checked some of the connections

I dont advocate anybody who is not gas safe touching their boiler but you have done it correctly. I would have done exactly the same

 

[Nik01029]

If I do stumble across a leak, or a new boiler fixes It I'll definitely post what the problem was!!!

 

[Scott_D]

You haven't yet confirmed its the heat exchanger?
By removing a couple of parts this can be confirmed

 

[sammathias]

I had a main hex leaking a few weeks ago...well i can only assume it was as it wasnt leaking when cold. Must of only.been leaking when hot. £310 hex and hours work and no call back or pressure drop as yet. Boiler was only.4 years old.

 

[jtsplumbing]

I had a main hex leaking a few weeks ago...well i can only assume it was as it wasnt leaking when cold. Must of only.been leaking when hot. £310 hex and hours work and no call back or pressure drop as yet. Boiler was only.4 years old.

Was it out of warranty ? was it an Ideal Logic ?

 

[sammathias]

Yes ideal logic 30. Was only fitted with 2 year warranty.

 

[jtsplumbing]

Yes ideal logic 30. Was only fitted with 2 year warranty.

Mine is a 9 year old Logic + may be a different Ex, £472 + £62 for new gaskets + Fixing kit £25, + labour so may be better to fit new boiler.

 

[philbury]

I was having the same kind of problem (I also have some underfloor) with a 9 month old top the range Vaillant before Christmas. It was installed by Vaillant themselves with 10 year warranty.

In a two week period it lost operating pressure and switched off on 4 occasions. It sometimes happened when switched off and sometimes during the day. Mostly when cold.

Vaillant could not find a fault and told me to have my system checked over and flushed. I did nothing. I am quite sure there are no leaks. It happened a couple more times. Then it stopped happening. I complained to Vaillant and they have promised that if it happens again I will get 5* treatment!

I already raised this issue on here and people suggested a secondary
expansion vessel. I never needed one with previous (Glowworm) boiler...

It’s not all that reassuring because I want to be able to trust the system to switch on after being away using the holiday programmer.

 

[johnduffell]

Always worth checking the charge in the expansion vessel. If it's charged higher than the cold pressure then you only need to lose a relatively small amount of water to drop the pressure down to 0.5 bar or whatever the height of your system is above the guage. It wouldn't blow off when hot so that issue usually gets overlooked. And of course it only happens if there is indeed a small leak.

 

[Nik01029]

**update**
Friday I had a new boiler fitted. (Vaillant ecotec).
Since then, the pressure has been much more stable, only dropping the amount that might be expected when the whole system has been drained..
're checked this morning, and it doesn't appear to have lost any pressure at All, before it was losing at least half a bar overnight.
So it looks like the heat exchanger was the problem...
1st impressions of the boiler are that it's so quiet I struggle to hear it!!!

Thanks for all the valued replies...

 

[philbury]

Well, it lost pressure again last night so Vaillant are going to have to come out again!

 

[Scott_D]

Vaillant out again? How many times have they been?

 

[ShaunCorbs]

Why when it's a leak on your system and not the boiler

 

[ShaunCorbs]

Vaillant out again? How many times have they been?

He's changed boilers