ferroli combi boiler pressure issue

[caseyjones1961]

we have a bit of a mare with our Ferroli combi boiler....had to bleed the rads recently then the boiler starts cutting out due to low pressure after lots of t'internet surfing I managed to reinstate the pressure on the analogue gauge on the boiler but now the digital readout says 7.5 bar...way too high but the PRV hasn't operated to release the pressure....I bled a good amount of water from a nearby rad the analogue gauge dropped but the digital one stayed at 7.5 subsequently the boiler just locks out and displays a fault code.
Could it be the pressure sensor playing up?

 

[bellairaphon]

Yeah more than likely. Which model is it? Maxima?

Nath

 

[AngelesPlumbing]

Check expansion vessel by press air nipple if no water coming out, if not then get air pump and check pressure refer to manufactures instruction what is correct pressure, dont forget turn off the boiler and must be cold

 

[caseyjones1961]

yes bellairaphon....its a maxima 35s....the only sensor I can find is called a "low pressure" sensor but I'm guessing if it's gone west then all sorts of stuff could go wrong?....it would seem that the analogue gauge is correct or the PRV would be draining like a good 'un?
Am I correct that the sensor is an additional safety feature that shuts everything down in the event of an "issue"....if its knackered and thinks the pressure is at 7.5 bar (as the display reads) it's then telling the pcb to shut the boiler down
Read something about taking off the sensor and cleaning it....I've had it off but can't see anything to clean....could be some crap inside I guess but if the problem is deeper then best get a new un and replace it.

 

[caseyjones1961]

so I got the new pressure sensor on today and still no joy....pressure is reading 7.5psi but the PRV is not operating....I've tried to reduce the pressure by bleeding a rad(a lot) but still the pressure appears to be high and doesn't drop at all, is there something I'm missing?....any suggestions before we get someone out?....I'm pretty much done with it.

 

[bellairaphon]

If you look at your display on the left hand side you have 3 rubber circles push the middle one in once it says BF release. If AF appears do it again till BF reappears. Try that and get back to us.

Nath

 

[caseyjones1961]

Thanks bellairaphon....tried that....first push I got af.... second push got bf but nothing else any different...nothings running and I've still got the F40 fault code displayed!

 

[bellairaphon]

Your looking at either ignition pcb or display board. I would get someone in as you have done all you can.

Nath

 

[caseyjones1961]

Thanks for all the responses...had a chap out today from BG.....after about 2hrs he got it working though I'm not sure what he did and even he seemed a bit surprised!
Anyway we signed up for one of their regular contracts now so I can get on with all the other important stuff I have to do....like building my garage.