Mysterious loss of pressure on Vaillant EcoPro?

[Stigster]

Thanks all. Non-specialist's question just to eliminate the hex thing: if the CH circuit is isolated (using lever valves) but the HW is still operating normally and there's no pressure loss (remained constant for 8 hrs overnight) , does that eliminate the heat exchanger 100%? The PRV outlet is dry (as is the wall by the pipe), and no loss of heat/pressure when it's HW-only operation

Thanks for eliminating the PRV outlet because I've lost count of the times people have told me "It's definitely not that" and that's exactly what it turned out to be!

 

[FourOaksBookworm]

I would say system leak then

Thanks. I just can't understand why we or the leak specialist can't detect 2-4 litres an hour of water escaping anywhere? It's got to come out somewhere right, even if there is a void under the suspended floor?

 

[Stigster]

Thanks. I just can't understand why we or the leak specialist can't detect 2-4 litres an hour of water escaping anywhere? It's got to come out somewhere right, even if there is a void under the suspended floor?

It can be amazing how much water a building can take before it shows sometimes. CHK's suggestion of isolating the boiler and increasing the pressure is suggested because it will hopefully speed up the process of getting the leak to show. It sounds dodgy on the face of it, putting more water into the building but that's probably what's happening anyway and ultimately it'll show when it shows and the overall amount of water escaping will be more or less the same either way.

Also, his suggestion of listening for the leak is a good one. At a higher pressure the leak should be a bit noisier and therefore easier to detect by listening. You'll need to do it at a quiet time though.

 

[FourOaksBookworm]

It can be amazing how much water a building can take before it shows sometimes. CHK's suggestion of isolating the boiler and increasing the pressure is suggested because it will hopefully speed up the process of getting the leak to show. It sounds dodgy on the face of it, putting more water into the building but that's probably what's happening anyway and ultimately it'll show when it shows and the overall amount of water escaping will be more or less the same either way.

Also, his suggestion of listening for the leak is a good one. At a higher pressure the leak should be a bit noisier and therefore easier to detect by listening. You'll need to do it at a quiet time though.

cheers for that. In a house with two teenagers and a gerbil, that's easier said than done . Leak guy is coming back tomorrow, I will suggest it to him (although he's already spent a day here with us all being out, and with sensitive microphones, and still not found it.

 

[centralheatking]

cheers for that. In a house with two teenagers and a gerbil, that's easier said than done . Leak guy is coming back tomorrow, I will suggest it to him (although he's already spent a day here with us all being out, and with sensitive microphones, and still not found it.

My money is in the under block and beam floor...so install a couple of ball o fix 22mm or 15 mm where the flow and return go in and out.Turn them to off. Put a pressure test on 2 bar for 24 hrs and see what happens if it holds its under the floor if it drops then let me know... two ballo fix dead cheap and take them out when you are sorted. Microphones huh window dressing for the desperate in my opinion !
centralheatking

 

[FourOaksBookworm]

My money is in the under block and beam floor...so install a couple of ball o fix 22mm or 15 mm where the flow and return go in and out.Turn them to off. Put a pressure test on 2 bar for 24 hrs and see what happens if it holds its under the floor if it drops then let me know... two ballo fix dead cheap and take them out when you are sorted. Microphones huh window dressing for the desperate in my opinion !
centralheatking

Thanks. Already have lever valves installed to F&R and have set these to off overnight, pressure maintained for 8-10 hours with no drop, so it must be under the floor.

 

[centralheatking]

Thanks. Already have lever valves installed to F&R and have set these to off overnight, pressure maintained for 8-10 hours with no drop, so it must be under the floor.

Put a camera and a life jacket on the gerbil and make it earn its keep. So you know where the leak its not nice. How much depth below the block and beam set up ? forget the mic idea not even nasa will pick it up under block and beam and you know its there anyway. put a diagram up of the layout, rads and the bulding generally.
chking

 

[FourOaksBookworm]

Put a camera and a life jacket on the gerbil and make it earn its keep. So you know where the leak its not nice. How much depth below the block and beam set up ?
chking

It's a suspended wood beam floor, depth to ground is up to 80cm in places. But the pipework is new (plastic pushfit), and isn't that deep under the insulation, maybe 30-40cm at most (it's a new extension)

 

[Stigster]

Microphones huh window dressing for the desperate in my opinion !
centralheatking

I respectfully disagree. Nothing wrong with using the old Mk. I eyeballs and earholes but if the microphone can pick up something the old meaty bits can't it's still a win and the leak is found either way (hopefully!).

 

[centralheatking]

I respectfully disagree. Nothing wrong with using the old Mk. I eyeballs and earholes but if the microphone can pick up something the old meaty bits can't it's still a win and the leak is found either way (hopefully!).

my money is on the gerbill plan !
[automerge]1575391568[/automerge]

It's a suspended wood beam floor, depth to ground is up to 80cm in places. But the pipework is new (plastic pushfit). So just make a few traps, or is your floor lovely or laminated ? chking

 

[FourOaksBookworm]

my money is on the gerbill plan !
[automerge]1575391568[/automerge]

It's newly fitted laminate (last 5 months). Not glued however. Not block n beam, but just wooden joists, planking and chipboards over insulation, then two thin 2mm layers of under-floor membrane (foam/plastic), then laminate on top. Sorry no diagrams available

 

[WC1]

You can buy a stethoscope off Amazon for under 5 pounds. I have used 1 for similar reasons. An automotive stethoscope is great for detecting flow in a pipe you can't access.