correct pressure for ravenheat rsf 82e?

[ben85]

Evening,

I've just added some Wickes rapid-dose inhibitor to my combi boiler and that all went fine. I found out that adding the inhibitor via the filling loop raised the pressure to about 1.8 bar (usually 1.4-1.5 cold). Then when I started the boiler up it and it got hot it went to nearly 2.5 bar so was close to shutting down. To remedy this I turned off the boiler and opened a bleed screw on the rads to take it back down to 1.4 (bearing in mind it hadn't cooled down but it was off) This was then taken down to 1.4 and I turned on back again.

It now seems to get hot-ish and then it shuts itself off again every 10 seconds. You can hear the burner firing and fan and then 10 seconds later shuts down and the process repeats itself.

Is this something to do with excess air in the expansion vessle in boiler:

just for reference boiler pressures are:

boiler= 1.3 bar ( cold)
expansion tank (measured by a little black knob meter under the boiler with a range from 0.1-0.5 bar) = between 0.3 and 0.4

I think I may have read someone on the internet that that dial should say about 0.2?, do I need to relieve the expansion vessle pressure by letting some air out at top of boiler or what else could it be?

Kind Regards

Bw

 

[Boilerman2]

You need to do the reverse you must checxk the vessel with the boiler drained of water and a drain point open, the pressure in the vessel should be pumped up to 1-00Bar, the boiler is the closed and the system refilled with water to about 1-20Bar, you may loose some of your additive so this may need topping up afterwards, but with the correct pressure now in the expansion vesse, the water pressure should not rise as rapidly! good luck