Vaillant 828 ecomax, loss of pressure

[shyde15]

My boiler has started losing pressure, so I tied a plastic bag to the outside pressure relief valve pipe and it's dumping water into it. Why is this happening ?

 

[kevplumb]

because at some time the pressure has been to high and lifted the valve

which prob now has carp under it

 

[shyde15]

I have just set the pressure to 1 bar and turned on the heating on and watched the pressure go right up to the max 3 bar and the water started dumping outside. But why is the pressure going up?

 

[bobw1956]

Because the expantion vestles needs repressurising or changing

 

[gas4you]

See FAQ's on how to check/repressurise an expansion vessel

 

[shyde15]

I have checked the expansion vessel’s pressure and it read 0.75 Bar of which it falls into the correct pressure value of 0.75 to 0.90 Bar, but the pressure does keep going up to 3 Bar and dumping water out of the pressure release drain off pipe outside when the boiler is operation. Is there a pressure senor switch what is meant to stop this pressure going too high??. Is the pressure senor switch the problem ?

Can anyone help please?


Steve

 

[thenuke10]

has the filling loop been disconnected, if not it could be passing

 

[mickyg]

assuming you've correctly checked the expansion vessel(by emptying the water from the boiler first) then I would check that the pipe connecting the expansion vessel to the system is not blocked. It will more likely block at the very point its connected.

 

[shyde15]

Yes the filling loop is is turned off

 

[thenuke10]

yes but is it disconnected as even though it is off it could be passing

 

[shyde15]

Yes, I have turn both valves off so there should be no water coming through, highly unlikely both valves are faulty

 

[Mark Br]

Yes, I have turn both valves off so there should be no water coming through, highly unlikely both valves are faulty

Yes but is it disconnected. If the valves are passing water it won't matter that they are turned off. Best to check rather than assume that this isn't the problem