New unvented system - ground floor losing pressure

[plastics77]

Hi there, wondering if anyone has any pointers, in the middle of a stressful refurbishment that was meant to finish a week ago! I am completely in the dark about boilers, but we agreed to the recommendation of a new pressurised unvented system that would feed direct off the mains (Vaillant ecotec, 300L cylinder for 5 bed house). This installation is part of a refurb of a late 1970's house, including installing 3 new bathrooms (tiling and sanitaryware), a new kitchen and new carpets and wood flooring.

So, most of the bathrooms have been re-tiled, and when they looked at the floors they noticed the pipes were 'metric' and needed replacing, so they replaced all the pipes in the bathrooms upstairs. Downstairs, the kitchen tiles have been laid and the ground floor cloakroom too. The plan was to start the wood flooring early next week, once the new boiler had been pressure tested - they have just done that and have said all works fine upstairs, but downstairs it keeps dropping pressure.

They are suggesting that there might be a leak in one of the pipes in the ground floor, although there is no evidence of any water leak and there were no issues with the older boiler and heating system before they installed this new unvented system. Is it the pressure of this new system that could have just blown one of the older pipes in the ground floor too? If they had said this could be a possibility we probably would have just stuck with the older boiler that was working fine for now!

Any ideas as to what I need to ask them before they investigate and decide sections of the ground floor now need digging up and pipes replacing? The project as expected has gone well over budget, and this was a nice Christmas present today
Thanks for any advice...gratefully received as very confused about the situation...

 

[ShaunCorbs]

what system did you have before ?

 

[centralheatking]

Hi there, wondering if anyone has any pointers, in the middle of a stressful refurbishment that was meant to finish a week ago! I am completely in the dark about boilers, but we agreed to the recommendation of a new pressurised unvented system that would feed direct off the mains (Vaillant ecotec, 300L cylinder for 5 bed house). This installation is part of a refurb of a late 1970's house, including installing 3 new bathrooms (tiling and sanitaryware), a new kitchen and new carpets and wood flooring.

So, most of the bathrooms have been re-tiled, and when they looked at the floors they noticed the pipes were 'metric' and needed replacing, so they replaced all the pipes in the bathrooms upstairs. Downstairs, the kitchen tiles have been laid and the ground floor cloakroom too. The plan was to start the wood flooring early next week, once the new boiler had been pressure tested - they have just done that and have said all works fine upstairs, but downstairs it keeps dropping pressure.

They are suggesting that there might be a leak in one of the pipes in the ground floor, although there is no evidence of any water leak and there were no issues with the older boiler and heating system before they installed this new unvented system. Is it the pressure of this new system that could have just blown one of the older pipes in the ground floor too? If they had said this could be a possibility we probably would have just stuck with the older boiler that was working fine for now!

Any ideas as to what I need to ask them before they investigate and decide sections of the ground floor now need digging up and pipes replacing? The project as expected has gone well over budget, and this was a nice Christmas present today
Thanks for any advice...gratefully received as very confused about the situation...

So when they put a 24 hour pressure test on the UFH what were the start and finish bar readings ? I would request a signed certificate timed and dated myself each visually checked by the main contractor So can you isolate the radiators upstairs from the naughty underfloor set up manifolds. Which UFH circuits drop..surely not all of them.
Just disconnect each in turn in pairs pump them up with a bit of mains and find your problem. After that its another problem I suppose but one circuit lala out of say 5 would not be the end of your floor. Or just destroy the contractor.
centralheatking

 

[Scott_D]

There was no mention of UFH?
What sort of test was carried out?

 

[centralheatking]

So when they put a 24 hour pressure test on the UFH what were the start and finish bar readings ? I would request a signed certificate timed and dated myself each visually checked by the main contractor So can you isolate the radiators upstairs from the naughty underfloor set up manifolds. Which UFH circuits drop..surely not all of them.
Just disconnect each in turn in pairs pump them up with a bit of mains and find your problem. After that its another problem I suppose but one circuit lala out of say 5 would not be the end of your floor. Or just destroy the contractor.
centralheatking

Oops I mistook under floor pipes for UFH but the same test principle applies. centralheatking

 

[plastics77]

Sorry, yes no underfloor heating anywhere!

They didn't mention any specific tests, just said we done a pressure test and its fine upstairs, where all the new pipes were put into the bathroom, but the pressure is dropping downstairs, where the floors have not been touched (apart from kitchen tiles and utility room, where the new boiler has been placed)

They said they will investigate further but it could be that some pipes in the ground floor might be leaking

The previous system was the previous owners, we haven't actually moved in yet, we were getting this all done before we moved in. I think it was a vented system, non-condensing boiler with tanks up in the loft - had recently been serviced and they said no problems with heating downstairs or upstairs, but the boiler was old and surveyor said had a 'knocking' sound so worth changing sooner rather than later...

 

[Scott_D]

A buyers survey probably would not have tested for leaks under the floor.
Pressurising old pipework can highlight leaks and weak spots.

 

[centralheatking]

We will have a think and try to give you an accurate course of action centralheatking

 

[plastics77]

Hi all, quick update and urgent advice please on this topic. So suddenly it all seemed ok and although not regularly or noticeably losing pressure over spring when we started using heating less, the pressure did drop once or twice and they asked us to keep filling it up back to 1.5bar.

More recently in last month or so, the pressure now drops from 1.2 bar to 0 overnight, around a 12hr period if the heating isn't on, and we wake up with no hot water or heating.

They came back and isolated upstairs from downstairs, kept it going for several days pressure stayed at 1.5 bar and no problem with heating upstairs (the works which they say involved some pipework change). As soon as they reconnected the downstairs, pressure dropped again so they say it's a slow leak in underfloor pipe somewhere and as they didnt do anything to those pipes its not their problem. However, as goodwill they stuck some sealant in saying 90% of times this works. They also re-bled all the radiators to make sure no air locks.

The pressure drop although initially very slow after this (1.5bar to hovering below 1.0bar, and everytime you put heating on it would creep itself up again to keep working), now is back to 0. I dont want to just keep filling up the system and I'm sure they will say it's a pipe leak issue now.

Before I contact insurers for track and access is there anything else I should ask these contractors to check that may still have been linked to their installation? Btw what does UFH stand for?

Many thanks

 

[Scott_D]

Post some pictures of the boiler, cylinder, expansion vessels, manifolds etc.
Might give us some clues

 

[plastics77]

Hopefully these pictures help?

 

[EvilDrPorkChop]

Tbf it doesn't look a bad job overall, and they've put additional expansion in which is good.

Regarding the leak, it's probably highlighted the fact when the system has gone sealed. It was more than likely leaking before, but the system refilling itself. The fact you've got pressurised has probably made it leak worse, however on the old system it would have only of got worse anyway than better.

Unfortunately you'll have to try and locate the leak.

 

[PETE 123]

have you tried a flir camera looking at floor when heating is on to see if a leak shows.

 

[plastics77]

Thanks- what's a flir camera? Thermal imaging? Not yet, I thought that would be next step via insurers track and trace...

Interestingly, filled it back up tonight to 1.5bar from 0, to get some heating for the young kids overnight. Now the heating wont come on, it is showing a F75 error code now. Before it was only showing F22, which would go once refilled.

Sounds like I will have to get in touch with insurers to help find the leak, but hope it isnt actually an issue with the boiler as I will be charged and referred back to the boiler contractor!

 

[plastics77]

Ok quick one- please.
They came back to bleed radiators and then seemed to bleed something on the unvented cylinder.
Now, the analogue pressure guage on the expansion vessel is measuring 0.4bar less than the pressure on the digital reading in the boiler.
E.g. this am boiler saying 1.4 bar, analogue dial off the expansion vessel saying 1.0bar!!

The plumbers say this is normal, it is measuring 2 different systems. That doesnt make sense to me, they have always previously been reading the same. Is this normal??

 

[Ben-gee]

The digital boiler one is measuring the pressure in the central heating circuit.

The manual dial one is measuring the pressure in the hot water system.

As your plumber says, these are separate.

 

[plastics77]

Thank you
So you could get pressure loss to below 1 bar in the hot water system, but still be ok at 1.4bar for central heating. If it is the downstairs hot water system that is losing pressure, does that mean the leak is in areas supplying hot water taps, e.g. toilet sink or kitchen, rather than radiators?
When I use the filling loops to re-pressurise the system it is the manual dial one, below the expansion vessel , that I am checking is increasing back from 0 to 1.5bar, but does that mean I could be overpressurising the central heating system above 1.5bar, if it is higher in that system??

 

[EvilDrPorkChop]

The manual gauge will be the correct pressure for the central heating (It’s nothing to do with the Hot Water) the digital gauges on the Vaillant’s always over read and never give a true reading. When the pump kicks in you’ll notice there’s positive pressure on the sensor and it goes up too.

 

[Ben-gee]

The evilDr is correct! The dial pressure gauge is on the grey expansion vessel for the heating system.
The hot water system has the white expansion vessel, no visible dial, my mistake.
So yes, both pressure reading devices are for central heating system.

 

[plastics77]

Ok thanks both, that makes more sense. They were always reading the same value until the last week or so where the digital vaillant reading started reading about 0.4bar higher than the analogue one. Pressure dropped again and I refilled to 1.5 bar a day or two ago. All fine. Today, had dropped again overnight, but this time after re-pressurising using the filling loops, the pressure went back up but the F75 code has arrived again so nothing working, no hot water no heating, very frustrating! I know the installer will say to just reset the boiler but not comfortable doing that - surely just because there might be a pipe leak , doesn't mean there is nothing wrong with the boiler - the F75 code has only started coming recently, could the pressure sensor have blown?

Will call insurers on monday to find the leak but worried that they will say there is a problem with the boiler that hasnt been sorted out yet..and until then we got young kids and no hot water or heating for a couple of days, nightmare!

 

[EvilDrPorkChop]

Ok thanks both, that makes more sense. They were always reading the same value until the last week or so where the digital vaillant reading started reading about 0.4bar higher than the analogue one. Pressure dropped again and I refilled to 1.5 bar a day or two ago. All fine. Today, had dropped again overnight, but this time after re-pressurising using the filling loops, the pressure went back up but the F75 code has arrived again so nothing working, no hot water no heating, very frustrating! I know the installer will say to just reset the boiler but not comfortable doing that - surely just because there might be a pipe leak , doesn't mean there is nothing wrong with the boiler - the F75 code has only started coming recently, could the pressure sensor have blown?

Will call insurers on monday to find the leak but worried that they will say there is a problem with the boiler that hasnt been sorted out yet..and until then we got young kids and no hot water or heating for a couple of days, nightmare!

Just reset, the worse than can happen is that it'll just do F.75 again.

More than likely theres dirt in the pressure sensor. They are very sensitive, and tbh a bit of a nightmare. You could try adding a tiny bit more pressure in, then reseting. That usually sorts it.

 

[plastics77]

Ok thanks, did it, worked.
Will just have to keep re-setting until they find the leak!

 

[Scott_D]

You can always turn on the immersion heater for hot water?
F75 is usually a boiler issue
Is it possible to leave the leaking zone isolated until it’s fixed?
I’m not sure if that boiler requires an auto bypass but I can’t see one in the pictures

 

[plastics77]

You can always turn on the immersion heater for hot water?
F75 is usually a boiler issue
Is it possible to leave the leaking zone isolated until it’s fixed?
I’m not sure if that boiler requires an auto bypass but I can’t see one in the pictures

Yup plumber not coming and insists not a boiler issue, says it's a leak that needs sorting. He said just keep filling up and resetting boiler until leak sorted. Good point re. Electric immersion heater, I'm not sure where that switch is on this new system, will have to ask.

They did isolate upstairs and no pressure loss, so they think leak is downstairs but no sign of water damage so no idea where. If we isolate off again, means no heating at all downstairs and things are going to get cold over next week or two.

What's an auto bypass??

 

[Vee]

Yup plumber not coming and insists not a boiler issue, says it's a leak that needs sorting. He said just keep filling up and resetting boiler until leak sorted. Good point re. Electric immersion heater, I'm not sure where that switch is on this new system, will have to ask.

They did isolate upstairs and no pressure loss, so they think leak is downstairs but no sign of water damage so no idea where. If we isolate off again, means no heating at all downstairs and things are going to get cold over next week or two.

What's an auto bypass??

Which model Ecofit Pure (Since its not an Ecotec) do you have? Does the model number start with 4 or 6. There is a badge on the underside?

 

[plastics77]

Which model Ecofit Pure (Since its not an Ecotec) do you have? Does the model number start with 4 or 6. There is a badge on the underside?

Hi there, it's an Ecofit pure 630

 

[Scott_D]

Yup plumber not coming and insists not a boiler issue, says it's a leak that needs sorting. He said just keep filling up and resetting boiler until leak sorted. Good point re. Electric immersion heater, I'm not sure where that switch is on this new system, will have to ask.


What's an auto bypass??

follow the cable to hopefully find a switch for the immersion

An auto bypass will open to give water somewhere to go if the pump is running but zone valves are shut.
Nothing to do with your leak problem

 

[EvilDrPorkChop]

All Vaillant System boilers have an auto bypass integrated so doesn't need an external one.