Worcester 28 CDI, pressure gauge not working

[Zehroni]

The pressure gauge on our Worcester 28 CDI stuck on 1 bar. I noticed it today when I drained the system to clean it with system cleaner. Has it gone and needed to be replaced or can I get working again with your help. Many thanks

 

[45yearsagasman]

The little capilliary tube will be blocked where it joins the boiler. Easy to remove and clear by removing the clip that holds it in. Remove all pressure and protect electrics.

 

[Zehroni]

many thanks for there speedy reply, I guess I need to drain the system again correct! . also how do I know where the blockage, capillary tube is long and thin and the blockage could be anywhere middle or end

 

[Tibbot]

As 45ygm states or the plastic manifold type housing the capillary clips into may be sludged and need a clean.

 

[Zehroni]

Tibbot, if that is the case then hopefully the system cleaner I have just injected in the system should do the trick. The boiler have been going for nearly an hour on middle temperature and I could see no singed fore the gauge moving a bit, it normally goes up by .0.2 or 0.3 bar.

 

[45yearsagasman]

Its very unlikely that system cleaner will do it. The only way is to remove the clip and clean where it connects to the boiler.

 

[Zehroni]

You are right, I injected the chemical at 2 pm this afternoon and the pressure gauge still locked at 1 bar. I will wait until I drain the system again in a week or 2 and take it off and clean it. I had a look at it, it is fairly easily to dismantle, only one clip attaches it the plastic manifold.

 

[Zehroni]

As 45ygm states or the plastic manifold type housing the capillary clips into may be sludged and need a clean.

Dear All,
I Removed the pressure completely from the boiler and still reads 1 bar. However, I found the capillary tubes where it joins the boiler covered with black greasy stuff, clean it and the gauge drops to zero. However, put it back again and it immediately read 0.3 bar and kept on 0.3 bat no matter how much water I put in the system.

I also noticed that e plastic manifold is very dirty, I cleaned a bit with a screw driver but the middle of it (looking at it straight) is still black. I did not want to scratch it hard in case I brake it .However, I could not see anywhere that the water can get into the plastic manifold from the system. My question is how the water gets into this plastic manifold so that the head of the pressure gauge becomes immersed in water?