Pressure Drop from 2 bar to zero in 12 hours

[Deflated]

I have moved into a new build, with a oil fired 'grandee' condensing boiler, and direct fed megaflow system. The plumber has changed the PRV and tested the expansion tank which is ok. There is no visible signs of a leak, although the pipes are under the screed on the ground floor! I suppose the large drop in pressure indicates a leak on some sort? could it be a component failing? or a boiler problem?

Can anyone suggest some reasons this maybe happening? Or things i could check as the plumber is now on holiday for a week! As the next thing he has indicated he will try is cutting the main pipes and pressure testing upstairs then downstairs to try and find the leak!

Any ideas would be appreciated

 

[giblets]

If it's a new "new-build" I would get the builder/developer to sort it out under warranty PDQ. By topping up the system with fresh water regularly you could be causing corrosion to the inside of the boiler/rads.

 

[Deflated]

Thanks Giblets.
the developers plumber has attempted to find the problem, like testing the expansion vessel and changing the PRV but no joy. He is away for a week or so then he is going to cut the pipes and try and pressure test which part of the system is leaking. I am just wondering what else could be attempted before that??
TY

 

[simond]

You could be losing water from the CH pipes or even into the primary coil of the Megaflo. Losing this amount of water is unusual and if CH pipes are under the screed then you would normally experience damp.

Might well be the Megaflo.

 

[Balenza]

Simond wrote

Might well be the Megaflo.

I was led to believe the primary section is at a lower pressure than the secondary side in an IED.
So if a failure happens then how can water leak from the primary side to the secondary side ?.
The OP's problem is most likely a leak under the floor.

 

[Deflated]

Thanks chaps for your input, if the leak is in the pipe in the screed, can the pipe be fixed with leak sealer??

Could the boiler be at fault in any way? If so can it be isolated to see if the pressure still drops?

Am i clutching at straws?

 

[giblets]

In view of your last but one post I would not attempt a repair yourself. Leave it to the developer. If this drags on too long then tell him that you will get it sorted and bill him for any costs involved. If still under warranty you must give him the chance to put it right and adding leak sealer is not going to work on a leak that big. It coud also gum up the boiler and invalidate the warranty on that as well.

 

[simond]

What is an IED?

There is nothing to guarantee that the primaries are at a lower pressure.

It is unlikely, but then it is also unlikely that you can lose a load of water into a screed, which will have a damp proof membrane under it, without detection.

Unless the solid floor has UFH, I don't know why it has pipes just buried in it. My understanding of current good building practice is that conduits are needed as a minimum when laying CH pipework in solid floors.

 

[John M]

What is an IED?

Improvised Explosive Device ....... Google Iraq

 

[Deflated]

Keep thinking guys its certainly keeping my grey matter working hard!

Simond you mentioned it might be the megaflow how would one find out if it was that?

I have also found a bleed valve on a rad that just turns both ways without any water coming out(it is not leaking though) its like the thread has gone could this be effecting the pressure droping?

It was a bit chilly tonight so i put the system pressure up from zero to 1.5 bar and put the heating on. I dont know if it is paranoia but the rads nearest the megaflow sound rattly a bit like there are small marbles being flushed threw them.???

 

[simond]

All I would advise you to do is exactly what we've all said, leave it to the developer. You will need to keep refilling while he makes you wait.

The worst faults we have are where the customer is waiting on the doorstep when we get there to tell us all the things they have tried, software they have reconfigured etc etc.

Like most in the trade, we'd much prefer to see the system in the same state it was in when it was installed - bar the fault.

By fiddling with things like bleed screws etc you will introduce air into the system, it will not, I'm afraid, aid a speedy diagnosis and repair.