Ravenheat CSI85 pressure going too high

[psarinuk]

Hi,

My Ravenheat CSI85T was dropping pressure at a very slow rate and the pressure gauge was indicating fairly high pressure at around 3 bar in the CH mode when the CH thermostat was set to 9 O clock (almost horizontal or lower).

So I looked at the wall outside and the pipe had some water in it, although it was not dripping. Found the Air purge vale as quite dirty with lot of brass rust around it, so changed that with a new one yesterday.

The boiler is now running fine (it was before as well) but the pressure gauge is still showing high pressure of 3 bar in CH mode and its losing pressure overnight. I also found a small puddle not far from the pressure relief pipe outside the house.

Do I need to change the PRV (pressure relief valve)? I've looked some other threads and someone advised check if its an expansion problem.
How do you check if the expansion vessel has got the correct pressure? i can't find the tyre valve to check/ pump air. please check the pic below and advise of its location.

Thanks

 

[Agile]

Read the FAQ about the EXV.

Its all in there!

Tony

 

[psarinuk]

Hi Tony,

Thanks for the reply. Its very useful guide indeed. However, I could not find any info about isolating the boiler from the CH if you can.

In my Ravenheat CSI85T, i have 2 valves (1 of them is very hard, sticky, needs pliers to move), that I can use to isolate the boiler. There is also a drain point at the bottom of the boiler.

If I isolate the boiler, can I leave the drain point open all the time till the pressure builds to 0.7 bar inside the vessel? That was all the water should come out anyway from the expansion vessel through drain off point?

 

[psarinuk]

For information to others who attempt this:
As advised in my post above, see if you can isolate the boiler and find a drain point on the boiler itself, then cycle the compression and release drain nut a few times (I did it thrice). The pressure has not gone over 2 bar since then and I am monitoring the leak as well.

The worst thing if you are working on a Ravenheat is the tyre valve. Its location is quite bad, well obscured behind the condensate drain pipe (looking from top). My compressor would not screw on the tyre valve. In the end, I had to borrow an elbow style screw latch compressor to get this job done. The supporting bracket for the expansion valve also tries its best to get in way.

But worth the effort I think in the end.