Help with boiler pressure please

[jackabe]

Hello folks
Can anyone help please.
Im having problems with a valliant echo tech plus (I think 928,cannot remember the the exact number).
It lost pressure a month ago with the heating and h/w on
Refilled it no problems up until last week.
The pressure dropped and the boiler started leaking from the diverter valve.
Called Valliant paid nearly 300 for their were fix it policy.
They came out changed the part rebooted it,and left.
All good,well for an hour then the pressure dropped again.this time within an hour.
The engineer came back tested a few things pressure in expansion vessel etc and said the dreaded four words. it must be a leak.
So good for him he said he would do one last check and isolate the central heating.Leave the h/w on and see if the pressure drops.
It didnt drop it rose,so far so that it turned itself off.
Called back and they said it was a plumbing problem.
Thank you to all that have posted on all other threads,have read hundreds but have not found one with both the same problems,as this one.
I have disconnected the filling loop,the end to the far left of the boiler,to see if it was turned off totally(thanks to other posters on this site).
It was not so took of grey tap thing and tried closing but wont close at all.It just drips constant.
So please if anyone could help.
Would that cause the pressure in central heating to drop dramatically.Or should I be still thinking about breaking up concrete floors and taking up floorboards.
Also would the filling part where the loop is come under valliant fixing cover.
If anyone could help please
Thank you
And thanks again to other thread posters

 

[TCCHeating]

Call vaillant back. You need a new filling link. Common problem on these boilers.

Once you have the filling link fixed. If the pressure is still dropping you have a leak.

But get the filling link fixed first

 

[jackabe]

Thank you TCC
Will the filling link be under their,Were fix it policy
Thanks again

 

[TCCHeating]

Yes.

The passing filling link is part of the boiler so should be included in the fixed price repair.

Engineer obviously missed it when he visited so if you call them and explain the problem they should send him back out free of charge

 

[jackabe]

Thats great thanks again.Will call them back in the morning.
Would in your experience, that cause the pressure to drop when the heatings on.

 

[AGAS]

you might have other problem just get filling loop sorted first

 

[TCCHeating]

Would in your experience, that cause the pressure to drop when the heatings on.

Could do because it would cause overpressure of ch system. When ch is turned on the expansion of water could cause prv to open. When ch cools down pressure could be too low for a while until the passing filling link fills it back up again. The process will continue like this.

Plus the fact that once a prv opens it might not shut off properly

Get the filling link fixed first and see if it solves your problem

 

[jackabe]

Will do thanks AGAS,they say they come in threes,just hope if their is a third one its not a leak..
Thanks again

 

[jackabe]

Thanks TCC
Feel a bit more confident now for when I get them back.Have had icy stairs from the other half for the last few days,about potentially tearing the floors up.
Fingers crossed and thanks again,Will let you know tomoz,how it goes.
All the best
Your a star

 

[jackabe]

Hello folks its me again.
Engineers been again.
definitely didn't seem to happy about having to come back,something about losing money if they get called back.
Anyway long story short he changed the filling link and prv. Thanks TCC Refilled and left.
I bled the rads and topped back up again.
Same problem again with when the central heatings on pressure drops within half an hour.
If it was a leaky rad valve,would their be puddles of water by it or would it evaporate instantly.
Think Im clutching at straws their,but hey live in hope.
Just dreading crawling around under floors....
Please if any one could offer anymore advice,I will be forever in your debt.
Thank you

 

[jackabe]

just a thought could it be air pockets in the system.As it dose not seem to take to long to fill pressure back up again.
Thank you

 

[AGAS]

you will need to check whole system for leaks I'm afraid , if you have no leaks on system you'll have to call valiant back on your fixed price repair to fix problem again which might need to change a major part within boiler . they can test if this is the problem .
are you sure your pressure is only dropping and not rising aswell as your original post .
edit . if leaking above floor level you would see water at that rate

 

[jackabe]

Hi AGAS
Thanks for replying.Well I just isolated the Central heating under the boiler and just left the hot water on,to see if it will rise and the pressure is still dropping.
Help

 

[jackabe]

Ive also taped a finger from a rubber glove to the bottom of the outside pipe.To see if that catches anything.

 

[Agile]

So boiler pressure is falling with the CH valves closed?

But have you watched it when you first repressurise it to 1.5 bar cold and then turn on the heating?

Tony