Boiler Water Pressure Problem

[theybe]

Hi there,

I have a Vaillant Turbomax 824/2 E Combi boiler.
I have a problem which is, the pressure gauge keeps dropping.
Everytime I use the hot water, I believe the water pressure gauge keeps dropping.
After using the water for a few days, the pressure gauge drops to 0.
I used to rectify the problem by turning the pressure back to about 1 and a half. It's got to stage now, that when I try to increase the pressure, the gauge is not bodging anymore. I don't know what to do, Does anyone have any ideas please?

 

[wilmac32]

you must have a leak on your system for the pressure to keep dropping.check the safety blow off valve is not passing,if that is ok then check your central heating system for leaks

 

[theybe]

For there to be a bad leak, which there may be.
I cannot see any dampness or physical leaks anywhere.
What is the blow off valve or where is it usually at.

If there is a leak, is there anything I can put into the heating sytem to stop this.

I have tried the radiator in the recent past and the heating is nice and hot. I just don't know.

I just replaced the gas valve, because it was affected, does this have anything to do with pressure.

Would it be a good idea to drain the system and start all ove again?

 

[wilmac32]

Blow off valve is inside boiler with a pipe off it run to outside property.Check this pipe outside to make sure no water leaking from it as even a small drip from it will drop pressure in system.Gas valve valve has nothing to do with pressure of water in system.

 

[corgiman]

Blow off valve is inside boiler with a pipe off it run to outside property.Check this pipe outside to make sure no water leaking from it as even a small drip from it will drop pressure in system.Gas valve valve has nothing to do with pressure of water in system.

but as a competent person who is not breaking the law you would know that, wouldnt you

 

[bripl]

he is just a competent diyer as we all know it is perfectly legal for a competent diyer to change a gas valve,and we all know how competence is proven? dont we?

 

[fitz1]

seen a few incompetancies. good work for bricklayers , roofers and window fitters. BANG

 

[theybe]

What I don't understand is the fact that the hot water and heating still works when the pressure goes down to 0. Should it not stop working cause there isn't any water according to the boiler/pressure gauge?

Any answers?

 

[Agile]

That boiler monitors a flow of water using temperature sensors before and after the main heat exchanger.

Its possible for the gauge to show zero but to still have enough flow to operate safely.

Only problem is that when there is not enough flow then it often overheats the sensors first and they have to be replaced at about £35 each.

Tony