Vokera Syntesi 35 boiler, losing pressure?

[ottosump]

Hi group, we have a Vokera Syntesi 35 boiler which is dropping to zero bar every other day, in the morning the boiler is flashing error code 4. I manually refill the loop and all is well for the next day or so. Anyone have any ideas what could be causing this?
Thanks to all, Otto West Cumbria

Untitled

• ottosump
• 19 Apr 2015
• 1

 

[PrenticeBoyofDerry]

I would firstly check a fittings on the central heating circuit for leaks, this would include, soldered joints, compression joints, the radiator valves and the end caps and bleed valve caps.
Check for damp spots around the radiator tails, this could indicate a rad valve joint or end/bleed cap leak.

 

[vulcancontinental]

There will also be a pressure relief vent outside below the boiler flue close to the ground (if it is all put in correctly). Check to see it's not dripping. If it is it's an easy fix but probably best not by you.

 

[ottosump]

Thank you for the reply guys, checked all the fittings and I can't see any signs of leakage, we live in a bungalow and many of the pipes run through the roof space, no water in the attic. Couldn't see the relief valve, did find a pvc condensate pipe approx 20mm in diameter, placed a jar underneath to catch any water, none found. Boiler is still losing pressure

 

[ianmcd]

vulcan as usual is on the ball here , when the system is cold note what the pressure is registering on the guage, then put the heating on and see if the pressure guage starts to register around the 3 bar level when the system heats up,if it does then you have an expansion problem , very common there are instructionson this site how to rectify but follow ALL the instructions

 

[ottosump]

Thanks for the reply, just so I can gauge, what pressure should the boiler be sitting at when not in use, ie cold.
Thanks Otto

 

[ianmcd]

anywhere between 1 Bar and 1.5 Bar when cold is normal but it doesnt tell you anything if this is not the case, it just tells you how much pressure is in the system if it is lower then increase it to these guidelines then switch the heating on and watch the guage , and see if it goes up within say a half hour period, an increase of say 0.2 of a Bar is normal but if the guage registers anywher near the 3 Bar mark then you have an expansion problem

 

[ottosump]

Hi group, these are my findings. I had the boiler cold sitting at 1.5bar, after running the central heating for 10 minutes I checked the gauge, it was at 2.5bar, then at 30 minutes I checked the gauge and it was at 3 bar. I then checked the empty coffee jar that I had placed below the plastic pvc condensate pipe, it was full of water. I then turned the heating off, checked the jar after an hour, it was full of water again. So my earlier statement about no show of water at the pvc condensate pipe was incorrect. Damn it!

 

[ottosump]

Any further suggestions would be appreciated.
regards Otto

 

[ottosump]

Quick update for those that have been kind enough to reply, apparently the expansion vessel diaphragm is at fault, I have been quoted £100-130 ex VAT to fix. A work colleague has informed me that an external vessel can be fitted by a none qualified engineer, can anyone advise.
Regards Otto

 

[ottosump]

Update: New expansion vessel fitted in loft, boiler OK for a week, now I've got an error code 7, but I think that is unrelated to the initial fault and that's a starter for a new thread. Thank you everyone for all the advice, much appreciated x

 

[Agile]

Might have been better to stick to this thread where we can read all about your boiler and its history.

Tony

 

[AGAS]

probably the primary thermistor

 

[ottosump]

Update: Primary thermistor replaced by my local gas man, all has been well for the past two months
Thank you all for your valued help.
Otto

 

[Agile]

Sounds like a temperature sensor.