Stuck autofill valve... Help

irishchris

System installed about 20 years back and had autofill valve installed on mains on pipe under hot tank. Over years have had to turn the knob on to manually add to system if pressure dropped too low.

On checking today pressure is just barely above zero but the valve on top won't turn. What can be done here and has anyone come across one that was seized.

There is also a threaded bar at bottom that looks like can be turned with pliers. Any advice on what this may be and wonder if the last time the plumber was working in hotpress if he closed this. Would this stop manual filling of system?

The picture below is similar valve to mine

John.G

First ensure no isolating valves that my be at either end of the PRV (pressure reducing valve) are closed. then turn the plastic knob anticlockwise as you are looking on it from the end until fully open, it may allready be fully open so turn it clockwise to check. Then turn the PRV brass screw CLOCKWISE slowly until the pressure starts rising, adjust very slowly until pressure is 1.5bar, the auto filling is now set, but I hate these as the system can slowly fill with oxygen rich air and lead to corrosion/sludge, a tight system should only require topping up once/twice a year, at most. If you want to check for leaks, just shut the plastic knob fully (clockwise) until next top up required, you can leave the PRV adjustung screw as is except the pressure keeps on rising, in which case, unscrew this (anticlockwise) again.

irishchris

No valves unfortunately fitted. The main problem I have is the plastic knob won't turn clockwise or anti clockwise.

The threaded bar at the bottom, does this have anything to do with locking the ability to top-up?

John.G

Just keep turning that adjusting screw clockwise, there might be no shut off on the bottom!!

Make sure you are turning the threaded bar clockwise DOWNWARDS, if still no water looks like the knobb needs more persuasion to open it?

irishchris

https://www.boards.ie/discussion/comment/120487213#Comment_120487213

Will give that a go when I get home.

When you say there may be no shut off on the bottom do you mean as in it may come undone?

John.G

No, I just mean that some PRVs don't have any shut off knob on the bottom, they just have that pressure adjusting threaded bar screw on the other end but if you used the knob previously then it should be possible to open/close it.