UFH - potential leak? Expert required! Complex??

[cronshd]

Hi

I hope someone can help - or point to where I can get some expertise on this.

Here is the description:

Location: Herts
Property: Bungalow (1960's)

Background:
Did major 8 month renovation project with reputable company in 2011 - moved back in Sept 2011.

Heating system is Ideal+ Combi boiler with UFH to lving/dining/kitchen areas and radiators in bedrooms.

All worked fine after initial hiccups were sorted out. Then, 11 months later:

August 2012 - No hw or heating - due to low pressure
Sept 2012 - Same again
Nov 2012 - And again
Dec 2012 - Same but this time the engineer was here for 2+ hours. He came up with the following analysis:

1. There is a leak somewhere, because the LED lights on the boiler are sensing water flow and water is passing through even when the valve is closed on the boiler. (That is my transcript of his words - please bear with me as plumbing is not my forte!).

2. The auxiliary expansion unit had failed and needed replacing. (he suggested this may possibly have been due to a slow build up of deposits caused by the leak).

3. There is no 'auto bypass valve' next to the zone valves/mainfold.

After the last incident I noticed that there was a noise - a bit like a kettle heating up which can be heard in the bathroom - even when all the heating system is shut down and no hot water is being used. I wondered if that was indicating the source of a leak.

I also noticed that the gas meter would still tick over even when the heating system was shut down and no hot water was being used. What is happening?

So today, the plumber who installed it all came back to investigate. After a couple of hours he concluded that there was a leak somewhere in the UFH. He is now suggesting taking up a tile to investigate. There are stone tiles and then screed .

I also called up a very helpful 'leak investigation' company who suggested it might just be a very slow 'weep' rather than a leak. He said that if the pressure was coming down half a bar in a week(?) then that is when they could use their thermal imaging/gas to check the location of any leak. (Which is not yet the case).

The other thing to mention is that gas consumption is up by +36-40% Sep-Nov 2012 vs 2011. Why is this? Back in 2011 we had the heating on much more as we had not fully worked out how best to use it - now it is on timers etc - so it should be much less!

I am really in need for someone expert in this kind of set up to do an analysis and provide advice/recommendations.

Any thoughts on action I can take is most appreciated.

Thanks, D

 

[CES]

From point 1 - Which valves are you talking about? If its the heating circuit valves then there is no leak on your heating circuit and Is probably more to do with your boiler. A leaking heat exchanger perhaps with the leak running away via the Condensate pipework?

I would be loathed to let someone lift a tile and then screed to investigate a leak on the UFH circuit (unless he can be sure there is one).
Your gas consumption is more to do with how your operating your heating system.
If the meter is turning when everything is switched off I would be concerned.
If you are unsure of your plumbers technical ability then I would suggest you get someone who knows more about this situation.
There is a section on here "Looking for a Plumber".

 

[Howsie]

What is the reputable companys response to this? It's them that should be doing all this for you!

Your gas meter should NOT be moving if all your gas appliances are off. That is your primary concern. Did you tell your plumber about this? He should not have left it like this.

Various ways to find leaks, some cheap and most expensive.

If I were in your position, I would touch nothing, correspond with the building company via email or letter and transcribe any conversations you have with them. It is their responsibility to problem shoot this and you may be giving them a get out clause if you touch it yourself or introduce another party.

 

[ecowarm]

Have the underfloor system pressure tested before anything is lifted..........

 

[cronshd]

Hi

Thanks for your quick replies.

With regard to the gas meter still being active when evrything is closed down, the plumber informed me today that this is because the boiler does a 'pre-heat'. It does not use up much gas according to him. (I measured it yesterday: in 4 hours it went up from 5573.4 to 5573.5).

On the valve question - pass I'm afraid. I just wrote down what he said.

 

[Destroyer2813]

I would be pressure testing the underfloor b4 I think of lifting tiles and I don't see the point in that because if there is a leak it could be anywhere under the floor

 

[cronshd]

I would be pressure testing the underfloor b4 I think of lifting tiles and I don't see the point in that because if there is a leak it could be anywhere under the floor

Thanks - with regards to pressure testing, can you describe the procedure - and what are they looking for?

I know it was pressure tested during the installation, but I was not present to see what happened.

 

[Destroyer2813]

During installation the system is tested at 6 bar for 1 hour and then reduced to 3 bar while the screeding process is taking place to prevent the pipes being crushed, this is based on polyplumb other systems may vary slightly. This process could be repaeated to determine if the underfloor is actully leaking or not

 

[cronshd]

During installation the system is tested at 6 bar for 1 hour and then reduced to 3 bar while the screeding process is taking place to prevent the pipes being crushed, this is based on polyplumb other systems may vary slightly. This process could be repaeated to determine if the underfloor is actully leaking or not

And what result would show that the underfloor is leaking?

 

[Destroyer2813]

If the pressure gauge on the test bucket drops over a period of time you could well have a leak, where in herts are you?

 

[lame plumber]

if pressure drop is small you cant do any harm by adding a fernox leak sealer to the system and seeing if that helps resolve the problem. also check for pressure drops with boiler isolated to confirm whether its a boiler issue or underfloor issue first.

 

[Destroyer2813]

Most modern boilers dont recommend leak sealer

 

[lame plumber]

I wasnt chatting to the boilers:tongue3:, but if there are leaks its cheaper than ripping up the floor and it works well some of the time, not always but considering the cost inplications why not try..

 

[Destroyer2813]

Not so cheap if the leak sealer blocks the narrow pathways inside the boiler though is it

 

[dancinplumba]

Not so cheap if the leak sealer blocks the narrow pathways inside the boiler though is it

you still liking baxi's destroyer ?

 

[Destroyer2813]

you still liking baxi's destroyer ?

Love em mate got one on every wall of my house :tongue3:

 

[cronshd]

If the pressure gauge on the test bucket drops over a period of time you could well have a leak, where in herts are you?

In St. Albans. Does that help?

On the question of the leak sealer - I guess that is a question for whoever is fixing it - although I noticed elsewhere (on a previous thread here?) that it might not be the best thing to do, depending on the pipes.

 

[lame plumber]

leak sealer works due to a reaction with air and if theres air in your boiler youve got a bigger problem anyway!