Can somebody explain - cant open valve

ShatterProof

The attached valve is connected to the heating system. I'm assuming that its to automatically top it up if the pressure drops. It never worked like that from day one. I always opened it manually and when the pressure was high enough i closed it again. This is located upstairs in the hot press.

Booked a service for the gas boiler next week and noticed the pressure was low so i though i'd better top it up before he comes. When i opened it no water came through. I dont undertand how it works properly ( somebody tried to explain once that the top screw controlled the rate of flow and the bottom one opened and closed it) . I played with all possible combinations fully on , half on etc..

Should the be replaced with one that works ????
Can it be replaced with a more simple switch.

Should the guy coming to servie the boiler be able to do it ???

Thanks

jeepers101

There's a little flat head screw at the top there. Did you try screwing that clockwise all the way and open the black knob.

jeepers101

Although it looks like there's 1bar in it already which should be enough.

ShatterProof

jeepers101 wrote: »

There's a little flat head screw at the top there. Did you try screwing that clockwise all the way and open the black knob.

Tried that. Had it fully in and turned black knob all the way, no joy. Also had it fully out and nothing either.

ShatterProof

jeepers101 wrote: »

Although it looks like there's 1bar in it already which should be enough.

That's a false reading. When the boiler starts the pressure gave always goes up about 1 bar. It was zero before it was switched on.

K.Flyer

What you have is an automatic filling valve.
The threaded piece is to increase the water pressure allowed into the system, which is usually set to about 1.0 - 1.25 bar when the system is cold.
You would start adjusting the pressure screw from fully anti-clockwise to clockwise and normally it would only take a couple of turns to achieve the correct pressure.
Turning the screw fully clockwise runs the risk of an over pressurised system and the safety valve on the boiler opening to let the excess water out.
Some of these valves gave a gauze filter on the inlet connection. If yours has, it may be blocked and needs cleaning. If their is no filter and no sign of a blockage, then most likely the valve will need to be replaced.
If the pressure gauge on your boiler is increasing by 1.00 bar or more from cold, then your expansion vessel may need attention. Normally if everything is in order the system pressure gauge will only increase by as much as 0.5 bar or less.

Joey the lips

I don't like or trust automatic filling vales. They mask leaks on heating systems and they can reduce the life of a boiler by causing sludge if there is a leak.

corkgsxr

Murder for seizing shut too.

Sometimes you get away with screwing the adjuster in and out sometimes it's disassembling and poking stuff lol