Vaillant T/Max Plus 824e, pressure gauge not increasing

[abc_plumb]

Hi guys

Need some help with this one.
I've put a new pressure gauge, increased the pressure in expansion vessel, but still nothing on the pressure gauge.
I removed the block at the back of the boiler where the pressure gauge fits in but that was clear.
I've checked the filling blocks but that seems to be fine, there is also a standard filling loop fitted on the flow pipe. The boiler is working but just can't tell what the pressure is in the boiler.

Any ideas what I can do?

 

[stevetheplumber]

usually its a blockge on the back block did you get a bit of wire through the hole?

 

[abc_plumb]

I was the 2nd engineer to go there.
The 1st one had snapped the pressure gauge at the block, so that whole connection had to be replaced.
I had a spare boiler which I took it from and fitted it, but the pressure gauge was new.
I did clean that block before fitting it.

 

[stevetheplumber]

then it must be a duff gauge

 

[abc_plumb]

Don't know why but didn't think of that?
The merchant won't be happy if I take it back

 

[Sim77]

read it again. Ignore previous post.