Hi.... and a combi boiler pressure drop query!

[tonyl]

Hi
Just joined forum as amateur DIY guy and wonder if anyone here can help me. I have a Vaillant 828 Turbomax Combi boiler which I’ve had for about 16 years old. I monitored the pressure yesterday & saw that it was quite low (around 1) so I topped it up to just over 2 and when I went back to it today it's dropped down to 1 again which made me wonder what’s wrong…e.g. an issue with the expansion vessel, fault on pressure gauge, leak, etc. The boiler still seems to be working ok still too. Thank you in advance for your help/comments. Tony

 

[SimonG]

1 isn't low.

 

[tonyl]

true... it was just under and there is a very slow leak so i like to keep it a bit higher

 

[Old Account]

I would not top the boiler to 2 bar once it starts expanding you will get a lot higher pressure. As above 1 bar is not that low

 

[Harvest Fields]

Above two is far too high.

 

[tonyl]

ok thanks so it was just below 1 and i put it up to just over 2 (tricky as have to turn screw underneath and cannot see gauge when topping up!) and the next time i looked it was back down to 1

 

[Old Account]

You may have an issue with your centealheating sysyem or boiler. If you are worry I’d recommend you to get a gas safe engineer out

 

[tonyl]

I know i have an issue, thought someone here might help the diagnosis

 

[SimonG]

If you know you have an issue then get a gas safe engineer. Not really up for 20 questions or guess the issue from next to no info.

 

[Millsy 82]

I know i have an issue, thought someone here might help the diagnosis

Go round and check for leaks on the rads and visible pipework. If you find them repair them If you don't find any then call someone in as you may have a fault within the boiler and you shouldn't be touching inside there.

 

[Darren Jackson]

Probably nothing wrong but a simple weeping joint somewhere. By topping up to just over 2 what happens is the boiler fires up & the heated water will expand, the pressure will rise and if it goes up to 2.5-3 then the pressure relief valve opens and dumps the water outside to protect the boiler and that is why it goes back down to 1 the next day. Just keep topping it up to 1 if it drops to 0.5 and either get someone in to check it all out or put up with it till you are replacing it all.