New Combi Boiler Pressure loss

[Paul JS]

Hi there,


Had a new WB 25i combi installed in Sept 2018 to replace an old WB combi (exactly same setup). Had all lockshields and Valves replaced at the same time.


A month later I noticed the pressure had slightly dropped from the original 1.5 and noticed a very slight leak on the connector to the condensate.


WB came out and replaced the part and another inlet as slight whistle when using hot water.


Solved I thought however a month later I noticed the pressure had dropped approx to 1.1 so I topped up however reported to the installers as shouldn't be topping up so frequently. They checked all the lockshields and valves, no obvious leaks or damp patches anywhere (the pipes are vertical in the walls downstairs).


Did the balloon check over the PRV exit outside over a few days to be sure - with no water at all.


WB came out to check the boiler again and couldn't find anything obvious however replaced the heat exchanger just in case.


I am now monitoring the pressure, however next step will be to isolate the boiler for a few days to see if it is the boiler or the system.


Any other ideas or how to find any potential leaks?


Thanks

 

[MeldrewsMate]

I think you have it covered with your last statement about isolating the boiler over a few days.
Did your old boiler suffer the same pressure losses?

I have had one occasion where a pinhole leak in the middle of a radiator caused the pressure to drop during the heating season, the water jet escaping was so fine it evapourated, but not when rads were cold. This was found after isolating the boiler and pumping up the rads to 10 bar hydraulically (after the previous fitter had changed the boiler!). Perhaps the powerflush could have opened-up a pinhole?

MM

 

[shambolic]

If hex has been changed and nothing out prv then 100% not the boiler leaking

 

[Paul JS]

Thanks for the replies, no previous pressure loss on the old boiler only had to top up very rarely.
The new system wasn't power flushed it was treated with cleaner then inhibitor with a magnafilter fitted. I'll isolate tomorrow as I also suspect something in the pipes or radiators has been disturbed.

 

[mcmoby69]

Repressurise, shut boiler off of flow & return, leave for 24 hrs and re open, pressure drop?
Leak on system . Pressure up? Boiler.......

 

[kev25v6]

Air in the system releasing out the automatic air vent causing the pressure to drop?

 

[Paul JS]

Could be, what's the easiest way to test, as WB engineer said it wasn't leaking water but obviously could be leaking air intermittently?

 

[dilalio]

Thanks for the replies, no previous pressure loss on the old boiler only had to top up very rarely.
The new system wasn't power flushed it was treated with cleaner then inhibitor with a magnafilter fitted. I'll isolate tomorrow as I also suspect something in the pipes or radiators has been disturbed.

Any new flooring put down in recent weeks/months?

 

[Paul JS]

no changes at all, I will check where the condensate was routed though as a hatch was cut in the floor to access outside - upstairs. thanks for all the replies

 

[Paul JS]

Update, turned off the flow and return for 48 hours, no movement in the pressure in the period then when reconnected no movement.
Very odd and implies something is leaking when perhaps under sustained use? Other strange thing was had a shower afterwards and the pressure increased slightly 0.1bar when the plumbing company said shouldn't increase after using the shower.

I have used the heating for a few hours last night and pressure is very slightly higher only marginal i.e. 0.05bar if anything, with a system temp on 21c vs when I reconnected.

Got another engineer coming tomorrow to check again.

Any other things it could be? next steps as apparently to check under floor will be chargeable and will involve cutting the floors/walls i'm left with no choice but to continue monitoring after tomorrows visit and pay for a track and trace (not covered under insurance).