Sime Friendly - Fluctuating Pressure Guage?

Hi I dont know if my experiance will be of help?
same happend to myself you have to much water if the system, use the drain hose just under the pump in the boiler so nothing shows on the guage, them by some means you need to fill the preasure vessel at the very rear of the boiler round thing nearest to the wall do it from the top.
The valve is just over to the RH side. its the same as a car tyre valve. electric compressor is the best, run off the battery charger. or a foot pump, fill this to 14lb or 1 bar. job done. test like car tyre with guage dont use the guage on the front of boiler as this should still read 0 (nothing) if it does let more water out via the hose and recheck the preasure vessel preasure.
Re preasurerise the boiler to 1 bar and see what happens should ok now..../...but if you loose preasure you have a leak on the rad side or the preasure vessel is knackered its about £35 ish if you shop around bit trickey to fit though but dead easy its in the manual, did mine the vessels are only preasure tested to about 4-6 max opp when they go over preaure the air leaks out around the of the vessel, you could as I did take the vessel off pump it up over preaure try it in the bath like a bike tyre to see if it leaks, if it dosnt brill put it back, if it doew let the air out and go round the outer seam edge in a vice and nip it up very hard, worked for mine and saves alot of hassle retry in bath for leaks and refitt, I would test at 3 bar air preasure in the bath test, good luck

5amp@v21.me.uk
December 2005