Vaillant boiler query

[steve d]

I have a Vaillant ecoMAX 828/2E condensing boiler. The pressure gauge at the boiler is .75 bar and I want to increase it to 1-1.5 per the manual. The reason I noticed the low pressure was I turned the heating up at the boiler with no change in heat at the radiators.

There is a built in filling loop under the boiler with a valve handle at either end. The one beside the pressure relief valve I can turn, the other one close to the body of the boiler doesn't seem to move. There's also what looks like a valve between the two filling handles on the flexi loop with a plastic cap with a 'cross' slot - what is this for?. I turned the filling handle (that does turn) about a 1/4 - no change in pressure.

Can you help?

 

[chrishutt]

The plastic cap will be the test point on the double check valve. You don't want to open that!

As for the filling loop valves, normally only the more central one is shut - the other being left open (although in theory both should be shut and the loop disconnected, but try doing that on a Vaillant!).

The valves are open when the slot is in line with the valve body direction - and shut when at 90 degrees to it. Are you saying one will not turn at all? Have you tried using a screwdriver rather than the key provided?

 

[steve d]

I am at work now and so can't look at the boiler. The valve handles are just a bit of plastic pressed onto a pin with two flats and in good condition. I suppose I could take that off and use a small shifting spanner? The valve handles are long triangular in shape so are they shut when this long direction of the handle is at 90 degrees to valve body?

What do you do to just increase the pressure a little at a time turn one valve or both handles 1/4, 1/2 turn. CH on or off?

The CH is working it's just I changed the temperature setting up at the boiler and didn't notice it changing throughout the house. Does a pressure of .75 bar have this effect?