Vailiant boiler pressure keeps rising

[Mali2]

Hi, the pressure of my Vailiant 831 combi boiler keeps rising when I turn it on. I am having to blead the radiator after every 2-3 hours of boiler being on to reduce the boiler pressure or the pressure bar goes to red. It seems like air builds up in the system when I blead the radiator the water has a lot of air bubbles, even when I use the hot water there is a lot of air bubbles. Hope someone can help, thanks[/b]

 

[picasso]

Make sure the filling loop is turned off.

 

[Mali2]

Yes, it is turned off, I still have the problem.

 

[Agile]

Remove the filling loop ( as the water Regs require anyway ).

If it still rises then there is part of the boiler failed which will be expensive to replace.

That is very rare though on Vaillants.

Tony

 

[easyas123Viessmann]

Does the pressure go down when the boiler cools. If it does it is the expansion vessel in need of a service.

 

[dreadnoughtheating]

Is there another filling loop left from a previous combi perhaps?
(The ecotec plus has a built in type, and some installers may forget to remove the old one from a previous install)

Dreadnought

 

[Agile]

I am always happy when my customers use the old filling loop!

Most chew up the built in ones!

Tony

 

[Mali2]

I am not sure if it is to do filling loop, the boiler was working fine, i used it for a lot during the cold period and suddenly it devolved this problem. No the pressure does not go down when it is turned off, it only goes down when I blead the radiator and the water that comes out has a lot of air bubbles.

 

[easyas123Viessmann]

Has a solution been found?

 

[leakydave]

IF this was an oil combi [which it isn't] I would suggest the hot water heat exchanger was passing water from the mains into the heating system.

Would this scenario ever crop up in a gas boiler?

 

[Mali2]

Unfortunately I have not found a solution yet.

 

[Bunnyman]

Get the inbuilt fill loop changed known problem