Boiler pressure - unable to get pressure to raise above 3/4 Bar

mike_2009

Hi,

Have an old SIME EV Comfort Gas Boiler and it stopped working over the weekend. Pressure too low - 3/4 bar. Used filling loop but no sound like it would usually make when topping up. Thought the valves on the filling loop might be faulty so checked these and water is flowing through both valves. I think there's something at the boiler end not admitting more water / higher pressure? The Air Admittance Valve in the boiler was replaced 6 months ago. It is likely just an air lock or something more troubling? Thanks!

Lenar3556

No - sounds like water simply isn’t getting in via the filling loop. Something is closed.

Do you have reasonable water pressure?

John.G

You may have a PRV (pressure reducing valve) on the filling line which needs increasing, post a photo of your top up system.

mike_2009

Pressure is 2-5 bar depending on the time of day. I'm not sure if the filling loop is gravity fed or mains fed though - assume gravity fed unless it tees off the mains as the filling pipe comes down from the attic?

There are 3 valves on the filling loop - 1 is permanently open (at top of pic), the second is a valve on the flexihose and the last is a lever valve below this. I undid the flexi hose and tested it and water come out and then the level valve heavily spurted water up so my assumption is there's no blockage and both are left normally closed unless a top up is needed. There used to be a different setup years ago but this was replaced by the plumber after other issues.

There is pressure there but it's not making any difference to the gauge on the boiler end of the system. Thanks all!

Lenar3556

Gauge on boiler may be faulty.

You mention the boiler isn’t working - Is it also showing a low water pressure fault? - I think it’s AL02 on the display.

greasepalm

I have a water pressure unit on top of boiler that i look at the odd time and if low i will go to hot press and open both valves and top up mains fed and can see gauge in there rising and shut off both when needed.

mike_2009

Thanks Folks - the symptom was cold water when having a shower a few mornings ago. I recall low pressure and seeing that AL02 alarm in previous years but you're right, no alarm this time, so maybe the gauge is faulty? I fired up the boiler which was just showing 20 degrees and no alarm and will let it run for an hour - it's up to 58 degrees so far. Not sure what happened a few morning ago so maybe there's something else going on, I'll see how it gets on shortly.

https://www.boards.ie/discussion/comment/120576560#Comment_120576560

Yep - I normally use the fill loop in the hot press to top up the pressure, but this time the gauge needle didn't budge which was new to me!

greasepalm

When i top up is late at night as pressure is stronger and i hear it flowing then.