Vokera 29HE loosing pressure

[morganlilli]

Hi all, at my wits end with this so appreciate any insights from the community...

Recently moved into a new house and Vokera boiler (Compact 29HE) started playing up virtually from day one. Required re-pressurising every few days and now this is a almost daily requirement that appears worse when heating has been on. It's loosing c2 bars a day routinely.

Had British Gas out who bleed radiators and pumped up expansion vessel but to no avail. Called out Vokera who serviced boiler and said no problems evident (think they also replaced the expansion vessel). Based on diagnosis from both, assumed it was a leak so had Dyno Rod out who have used thermal imaging and some kind of noise technology to seek leek - nothing showed.

Now not sure what to do next...could something have been missed?

There is evidence of a very small loss of water through the pipe that exits the house (sorry don't know the name) and also evidence of a very small leak from inside the boiler, i.e. Pipe 4th from left that exists boiler has slight trickle of water and appears to have been leaking for some time. Both British Gas and Vokera have told me that neither of these would explain the volume of pressure we are loosing. Other than that, a few radiators have signs of slights leaks on some pipe joints but no significant water loss.

Help!? Really appreciate any thoughts or advice from this forum in terms of anything else to check...or next steps.

Thanks

 

[diamondgas]

:welcome: here to the font of all leaking knowledge morganlilli

Sounds like you've had some "experts" visit....... 1st stem the drip from the outside ... that's an obvious 1st base fault check to be honest ... untill that's stemmed you're at a loose end as to where next to look IMHO

 

[JAP&H]

Hi Morganlilli.

Are there any pipes supplying radiators that are buried in solid floors?

 

[morganlilli]

Thanks Diamond Gas. I taped a bag over the pipe on the outside of the house a week ago and there was a small amount of water (few table spoons) after 2 days. Both 'experts' told me this wasn't enough water to worry about but I will repeat tomorrow and see if water is still being expelled.

 

[morganlilli]

Hi Jap&a - yes, most on the ground floor are in concrete floor. The Dyno Rod chap said the thermal imaging should have picked up any leak on these (nothing showed)?

 

[JAP&H]

How long we're Vokera on site?

Changing expansion vessel long winded on compact if you have clearance above to lift it out once horizontal flue (if fitted) is removed.

If haven't got sufficient clearance above then it's boiler off the wall to renew expansion vessel.

Just wondering if it was changed.

 

[M.Joshi]

When you repressurise from no pressure (0 bar), does the gauge needle gradually rise or shoot up?

 

[mcniven]

if the expansion vessel has been replaced, and the prv (the pipe outside) is not causing a lot of water .... then u 100% have a leak somewhere.

 

[morganlilli]

Hi jap&h - Vokera on site for about 2 hours. I was at work, so wife let in and left alone...difficult to know for sure what work was actually done. The boiler definitely was not removed from the wall though.

 

[morganlilli]

Hi MJoshi - pressure rises gradually when filling loop is opened. Takes about 1-2 min to go from 0 to 1.5 bars

 

[diamondgas]

Thanks Diamond Gas. I taped a bag over the pipe on the outside of the house a week ago and there was a small amount of water (few table spoons) after 2 days. Both 'experts' told me this wasn't enough water to worry about but I will repeat tomorrow and see if water is still being expelled.

It shouldn't pass anything at all! Period to be honest! nothing!! not a drip! Ever! Unless theres a problem

However as mentioned. I think, check what happens to the gauge reading from cold to heating fully heated. It should never creap up towards the 3 bar mark. If it does then be concerend regards pressure vessel issues IMHO .... Good shout regards concrete floors also .. you'll never know if it's leaking under or into that !!!

 

[M.Joshi]

Is it a plastic pipe or copper pipe that is leaking? Could be condensate.

 

[morganlilli]

M.joshi, it's copper

 

[M.Joshi]

M.joshi, it's copper

Hmm, that would be the pipe from the PRV (Pressure Release Valve). Seems as though its letting by. That's not normal. As others have said, does pressure on the gauge rise towards 3 bar when the boiler is heating?

You mentioned that it is loosing 2 bar daily. Are you pressurising the system to 2 bar?

 

[morganlilli]

Hmm, that would be the pipe from the PRV (Pressure Release Valve). Seems as though its letting by. That's not normal. As others have said, does pressure on the gauge rise towards 3 bar when the boiler is heating?

You mentioned that it is loosing 2 bar daily. Are you pressurising the system to 2 bar?

Sorry for the delay. Been away for a few days. The gauge does not rise when the heating is turned on. However, perssure is lost rapidly once the heating is engaged.

I am currently re-pressurising the system to 1.5 bars every time it drops out (was originally going to 2 bars as advised by BG man, but have since read it should be less).

Any thoughts?

 

[morganlilli]

Is it a plastic pipe or copper pipe that is leaking? Could be condensate.

After your note I had a look at the plastic pipe as well (the one that goes to the waste). I haven't disconnected this, but there is definately water going through here also when the heating is on as it's warm to touch. In fact, the pipe is still warm when I trace it to the toilet (next door). Is this normal. Only happens when the heating is on.

 

[morganlilli]

How long we're Vokera on site?

Changing expansion vessel long winded on compact if you have clearance above to lift it out once horizontal flue (if fitted) is removed.

If haven't got sufficient clearance above then it's boiler off the wall to renew expansion vessel.

Just wondering if it was changed.

Checked with the wife again, and she said it was close to 30-60min. Would this be about right?

 

[JAP&H]

The plastic pipe connected to the waste is to get rid of condensate.

From your earlier post, does the combi only lose pressure when there is a demand for heating?

If left alone, or only used for hot water does the gauge still drop?

 

[JAP&H]

Checked with the wife again, and she said it was close to 30-60min. Would this be about right?

The boiler would need to be drained, possibly disconnect flue (if it was routed to rear of combi). Disconnect expansion vessel and lift out. Position and connect new vessel, replace flue and re-pressurise appliance. And carry out a service.

Have'nt seen the set up but achieving all this in an hour or less seems unlikely.

 

[morganlilli]

The plastic pipe connected to the waste is to get rid of condensate.

From your earlier post, does the combi only lose pressure when there is a demand for heating?

If left alone, or only used for hot water does the gauge still drop?

It loses it much quicker when the heating is on....but still drops over time. To give you an example, I have to repressurise almost instantly once heating has been on. When just water, we can go 2-3 weeks.

 

[morganlilli]

The boiler would need to be drained, possibly disconnect flue (if it was routed to rear of combi). Disconnect expansion vessel and lift out. Position and connect new vessel, replace flue and re-pressurise appliance. And carry out a service.

Have'nt seen the set up but achieving all this in an hour or less seems unlikely.

Mhhh, pretty sure the system was not drained. Pic attached if this helps.

 

[Millsy 82]

After your note I had a look at the plastic pipe as well (the one that goes to the waste). I haven't disconnected this, but there is definately water going through here also when the heating is on as it's warm to touch. In fact, the pipe is still warm when I trace it to the toilet (next door). Is this normal. Only happens when the heating is on.

Yeah you will have water go down there as that is the condense pipe. It could be a number off things by the sounds of things I would get BG or vokera back and tell them that the problem is not solved.

To me it you may need a new PRV and to repair the leaks on the rads. You may also have a partial blockage going to the expansion vessell or a faulty secondary heat exchanger. Or they havnt done the job properly when re charging you exp vessell.

 

[JAP&H]

It loses it much quicker when the heating is on....but still drops over time. To give you an example, I have to repressurise almost instantly once heating has been on. When just water, we can go 2-3 weeks.

Definately sounds like a leak on the system pipework.

If there are no obvious signs (wet flooring, stains on ceiling) then although an infrared camera has been used my thoughts still tend towards concealed pipes.

 

[Millsy 82]

I would not have thought they could have changed an expansion vessell in that photo in an hour as they would have to disconnect the flue. I would say they have recharged it.

 

[morganlilli]

Also, here's a picture of the leak under the boiler (although this is a real slow leak)...took a few days to dampen a tissue wraped around the pipe. This is constant whether or not the heating is on.