Self Bleeding Radiator Valves? opinions please.

Pique · 10-01-2026 11:33PM #1

Anyone used these things?

3 rads upstairs are constantly air locked. Like every other day they need to be bled.

I've no idea why and can't afford a plumber to go Sherlock Holmes on the house atm. I've an oil boiler and a back boiler but due to incompetent plumber it's only a 3/4" pipe instead of inch which I was told is a blocker if I want to fit a stove but no idea if it's causing the airlocking.

Anyhoo, does anyone have experience with those self bleeding valves or am I mad to think they would be a solution?

Upstairs is timber not concrete so I don't want leaks if I go away for a week and come back to a destroyed house.

What say you?

10-10-20 · 11-01-2026 12:23PM

Hi, if you're getting that much air then you have a leak in piping or an expansion vessel, or the top-up isn't working. I'd double-check that the system is holding some reasonable amount of pressure (indicating that it's being topped up) and then if it is I'd add in a leak sealer.

https://www.heatmerchants.ie/plumb7-heating-system-leak-sealer-u73859

I hope it helps.

Pique · 11-01-2026 01:06PM

Not sure I understand.

It's not a pressurised system.

mikehn · 11-01-2026 01:33PM

Check the header tank in the attic.

10-10-20 · 11-01-2026 01:44PM

https://www.boards.ie/discussion/comment/124137491#Comment_124137491

No, but it has to be getting top-up water from somewhere.

https://www.boards.ie/discussion/comment/124137547#Comment_124137547

Exactly.

whizbang · 16-01-2026 03:52PM

You are loosing water big time.. fresh water into the system is so much more corrosive, that your whole system is probably eaten away inside.

if its a new thing, get it sorted properly now, or in a few years time you are replacing every single bit of that heating system.

The Continental Op · 16-01-2026 06:49PM

Doesn't have to be a leak. Check header tank incase hot water is being dumped back into it (pump set to fast) where it will absorb more air.

Pique · 17-01-2026 01:29AM

No signs of any leaks.

Haven't been to the attic to check yet. What should I expect to see in the attic while the heating is on and hit if there was a problem? Hot water feeding from the cylinder into the header tank?

Someone did mention the pump setting to me before but idk what's the correct setting.

There is a known flaw with the plumbing that hasn't been fixed and I dunno if it maybe contributes to the issue. Maybe you can tell me.

I've a back boiler in the living room. But the pipe to the cylinder is 3/4" instead of 1". Would that make a difference to anything?

This part of the development is fraught with cockups in the build so nothing would surprise me (circulation pump wasn't wired correctly on day 1 so lighting a fire resulted in boiling water pissing out the overflow to the garden. Had to run and grab a bucket of sand to quench the fire and turn on all hot taps.)

But the airlocking has gotten worse recently so maybe there's a leak somewhere hidden. The leak would have to be in the heating circuit I presume? Perhaps out at the boiler itself?

10-10-20 · 17-01-2026 03:15PM

You might find that the cold tank is warm, or that water is pitching into it from an overhanging pipe. Take photos while you're up there.

whizbang · 23-01-2026 01:53AM

Doesn't have to be a leak. Check header tank incase hot water is being dumped back into it (pump set to fast) where it will absorb more air.

air replaces the water alright, if we are talking the volumes the op is suggesting, the water will then overflow from the tank.

The Continental Op · 23-01-2026 10:50AM

https://www.boards.ie/discussion/comment/124172018#Comment_124172018

Air doesn't replace the water. If its moving around in contact with the air it will absorb ~~water~~ sorry air.

Cold water can absorb more air than hot water.

In hot water the air comes out of the water in the OP's rads.

I've no idea if that will be enough to create the issue the OP has but its possible.

youtheman · 28-01-2026 03:51PM

https://www.boards.ie/discussion/2058430937/self-bleeding-radiator-valves-opinions-please

I tried those radiator vent valves. They look lovely, but unfortunately they did not work. Still had to bleed the radiator regularly.

Self Bleeding Radiator Valves? opinions please.

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