Worcester Greenstar losing pressure

[muggo]

My 2 year old Worcester Greenstar 4000 is losing pressure I have to pressurise a couple of times a day & sometimes it can go from 1.2 bar to .3 bar in a matter of minutes. Other times it will go from 1.2 bar to .7 bar overnight. If I'm away for the weekend, it will be at zero when I return.
No air getting into the radiators & no visible leaks anywhere, even at the pipe manifolds.
Is it possible the water is being lost to the external drain pipe, hence why I can find no evidence of a leak or air in the radiators?
Is it probable the fault is with the boiler & not my existing heating installation?
TIA

 

[terryplumb]

Does pressure rise to 3 bar when heating is on ?
Have you checked the external pipe from the PRV ( pressure relief valve) to see if water has been coming out of it ?
Are there any heating pipes buried in concrete floors or underfloor voids ?

 

[muggo]

Does pressure rise to 3 bar when heating is on ?
Have you checked the external pipe from the PRV ( pressure relief valve) to see if water has been coming out of it ?
Are there any heating pipes buried in concrete floors or underfloor voids ?

Thanks Terry.
I'm pretty sure it's never been as high as 3 bar in its life. I set it as 1.2, but haven't checked for an increase when heating on. I can check later.
External pipe is attached to the outside wall & feeds into a drainpipe so I have no way of seeing if there's a flow.
Heating pipes run in ducts under concrete floor, No water running back into manifold chamber (lowest point?) & plenty of leak stopper in the system on a just in case basis.
Cheers, Paul

 

[terryplumb]

Show us a picture of external PRV pipe ,it would normally be copper and open ended ,not connected to a drain pipe ?
The condensate pipe is plastic and that would possibly be connected to drain pipe and misleading you.

 

[muggo]

Show us a picture of external PRV pipe ,it would normally be copper and open ended ,not connected to a drain pipe ?
The condensate pipe is plastic and that would possibly be connected to drain pipe and misleading you.

Now I understand. The curved copper pipe is not leaking water.
When cold, I set the pressure to 1.2 bar. Now it has been running for 10 minutes, it's at .9 bar. I expect it to drop further & stop the heating process.

 

[terryplumb]

Then there is a leak on the system pipework / radiators,or within the boiler. Possibly the heat exchanger is pin holed and water is escaping through the condensate pipework into the drain.

 

[muggo]

Then there is a leak on the system pipework / radiators,or within the boiler. Possibly the heat exchanger is pin holed and water is escaping through the condensate pipework into the drain.

Thanks Terry. Now the trick is to find which one it is!

 

[terryplumb]

Close the boilers flow and return isolation valves ,leave boiler off overnight,see if pressure has dropped tomorrow.
Ensure system has cooled down fully ,top pressure up to 1.5 bar before isolating.
If pressure hasn't dropped tomorrow,open flow and return isolation valves ,if pressure drops immediately the leak is on the system side.