Hi,

Apologies in advance for my lack of technical terminology, I'm no plumber.

I've got an 'issue' with my Sime Friendly boiler. The hot water is fine and the heating is fine, but....

Heating off: Pressure guage reads 1.5 bar.
Heating on: Pressure rises until the reading is maxed out - it hits the pressure needle limiter - This is probably around 5 or 6 bar. I tend to switch the heating off again at this point!!

I've been told that it could be lack of pressure in another part of the boiler causing the reading to fluctuate and that I should try and find a schrader valve that a pump can connect to (like a bike pump). I've found the valve and connected a pump but the reading was 0 bar. I've since pumped this up to around 1 bar but the guage still fluctuates when the heating is on.

The valve is connected to a large red 'tank' at the back of the boiler which is accessed from above.

Question 1: Does anyone know how much pressure I should pump into this tank?

Question 2: Does anyone know of a website where I may be able to find this information - I can't seem to find a site for Sime?

Question 3: Is it safe to leave the heating on with the pressure reading as it is or would I be better off leaving it off? It's possible that it's always done this and that I simply haven't noticed it before - I just happened to glance at the pressure guage one day last week.

Many thanks in advance,
Matt.

Matt Watkins, November 2005

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