Baxi 105e pressue not holding

[alwest197]

I've posted a couple of times regarding recent issues with my combi boiler and received great help..esp from muggles. Long story short...(my version it may not be totaly correct).. I had the PV replaced ( because it was leaking) by the guy who fitted the original system, 9 years ago. I then noticed that the pressure in the new PV was going up, so much so that I had to keep realising the pressure though one of the radiators. I posted on here (could not talk to the boiler guy..no problems at all with him but his wife was very ill so did not want to disturb him) After posting Muggles suggested that the plate heat exchanger DHW had probably got pin holes in it. I now assume this is what caused the original PV bladder to blow and the ensuing water rusted the PV and started to leak..
Right still with me?
Muggles gave me the part numbers I required for the new plate HEX and I duly fitted it...no problems at all.

Now my new problem is the pressure is now not holding to its 1-2.5 standard...I have to keep topping up...now I expected a little of this due to the oxygen coming out of the water and me releasing this via radiator bleeding...but its been a couple of weeks now and I'm still topping up every other day or so...

I thought I must have a leak somewhere but have checked all the rads, all around the boiler and pipe work as much as I can and nothing found. I am now stumped...

Any thoughts gratefully accepted as ever...

Al

 

[lexington]

I take it you have checked the safety discharge pipe and it is not coming from there? You only need a very small leak on these systems to drop the pressure, I suggest you check each rad valve by wipeing your fingers around it and see if you notice any water, if not then it could be a pipe which is under the floor, you can inject a leak sealer like Fernox into the system and it will automatically seal the leak , providing it is not too big. this may take uto 6 weeks to work, and you will have to keep toping up till it stops, but it will not work on large leaks.

regards

Maxgas

 

[alwest197]

Thanks..I'll have another look at the rads and pipes..if I still don't find a leak I'll go down the sealant route...

Al

 

[alwest197]

I've not found any leaks inside...but...I have noticed that the external overflow pipe has a leak...judging by the water down the wall..

Am I right to suspect the Pressure release valve? and if so what do I have to do to fix it.....?

New valves appear to be about £10 all in....

pressure still dropping over a few days...right down to below .5 bar..

Al

 

[Heating one2one LIVE]

Expansion vessel needs a recharge.

 

[alwest197]

thanks..I'll have a look at that tomorrow..
Al

 

[fine tune]

it needs a new pressure release valve , drain boiler disconnect pipe undue small allen key grub screw and pull , have a towel ready to catch any water

 

[alwest197]

Thanks..I'll give it a go.. and report back

Al

 

[alwest197]

PRV (innards only) fitted yesterday and it seems to be holding..

So thats a new Pressure Vessel - £150 - fitted
a new diaphragm kit for DHW - £9 - DIY
A new Plate heat exchanger - £35 - DIY
A new Pressure release valve - £29 - Fitted

I'm hoping that the end of it now..

Thanks for all your help

Al