Open system sucking in air, closed system still sucking in air! Any help or pointers?
- Thread starter kugaman1
- Start date
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Its been 20 years since we moved in and this has been an ongoing issue!
If the boiler is the top of the system, do you have an AAV open?
Also check rad valves.
Also check rad valves.
Hi, yes boiler is at the top of the system…no idea if there is an AAV or how to tell if open? Its a worcester bosch condensing boiler, dunno if theres an aav inside? Certainly nothing added outside.
And you say check rad valves? What to check? They all work as they should and there are no leaks.
We will get to the bottom if this one way or another!
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But the sealed system is only installed 6 months!, still ample time one would think for any air to disperse, its a pity (or maybe you did) read some of my posts before you went sealed, re OV systems, I have a OV system installed over 50 years ago with some rads over 40 years old, it has a combined vent&cold feed and gets the (very) odd drop of inhibitor, not a single problem, some who had problems even with the much praised VCP system converted to mine, no more problems.
Anyhow, back at the ranch, check your MIs that the boiler flow is on the far left as you look at the boiler, (where your pump is pumping from?), there seems to be slight staining at the inlet connection?, wonder if rubber gaskets were used on installation? which are the best.
Also don't forget to check out where the EV outlet tees in, its surprising, in view of the restricted space, that a heat only boiler was choosen, a system boiler, with integral pump and EV would have been neater, if nothing else.
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Check all your rad valves ,sometimes a weep can let air get sucked in to the system
Have you checked it is air and not hydrogen.
Also looks like staining near the filter
Have you checked it is air and not hydrogen.
Also looks like staining near the filter
Has it been a sealed system for 20 years then? If it is not dropping pressure give it time.
Follow the flow (outlet) pipe from the boiler. Does it go to the pump first (with the EV connection in between) then the diverter valve and rads/HW cylinder, or the rads first then the pump?
Just for curiosity, how high was the F/E tank before it was removed?
System sketch?
Hi all,
Ok, heres a system sketch from what I can see.
Hope it makes sense, Im no Picasso!
The boiler, magnaclean and PV are all in the loft, approx 3M above ground level.
The pump is a Grundfoss UPS2. Ive checked the compression fittings, all are good and tight. Pump flow is pointing the correct way.
The cold water feed tank was literally 20cm higher than the boiler when removed and pressurising the system.
Ok, heres a system sketch from what I can see.
Hope it makes sense, Im no Picasso!
The boiler, magnaclean and PV are all in the loft, approx 3M above ground level.
The pump is a Grundfoss UPS2. Ive checked the compression fittings, all are good and tight. Pump flow is pointing the correct way.
The cold water feed tank was literally 20cm higher than the boiler when removed and pressurising the system.
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OK - Stop the bus - it's been said the system is collecting air and it's definitely not gas (H or otherwise). It's also been said that the system doesn't lose pressure and that almost half a litre of water is being 'bled' to get rid of the air. It's also been mentioned that the system pressure stays solid and doesn't drop.
I'll be honest, with all that info I'd have to say that It doesn't seem like there is an issue with excessive air in the system, at least not a lot. If there was then the system pressure would invariably drop as the water was released. Air ingress into a sealed system means that water is being released and replaced by air. As that air is then compressed then there would be an indicative drop in system pressure. I look after countless systems where if the rads are being bled it sometime seems as if air is being expelled at the same time as water is (it seems to the way bleed valves work sometimes) but when the system is turned on the rads are fully hot to the top, meaning there actually isn't any air in it. If there was air then the rads would normally be cold along the top edge until the rad's fully hot and then the metal convects the heat upwards.
When the system is cold and then turned on, monitor the rad that seems to collect the sir and as the flow pipe heats up, check the top of the rad, if it heats up, then it can't be excess air.
Ok thanks….
I can assure you that there is LOTS of air being forced out when I bleed the system.
In daily use, the system doesn’t lose pressure. Obviously it loses all pressure when I bleed the air out (and the associated water).
Maybe I should leave it without bleeding for a month or so and see if the level actually does drop? At the moment, when the heating is on, I could bleed it daily and get lots of air out.
If I don't bleed the system while in use for a week or two, we frequently hear the air moving around through a couple of specific radiators.
I wish there was a facility to upload videos, I could show you how much air is coming out of one specific radiator.
I might order an aladdin autovent and put it on that specific radiator…..see what happens then?
Again thanks to all for your help, Im determined to get to the bottom of this!
I can assure you that there is LOTS of air being forced out when I bleed the system.
In daily use, the system doesn’t lose pressure. Obviously it loses all pressure when I bleed the air out (and the associated water).
Maybe I should leave it without bleeding for a month or so and see if the level actually does drop? At the moment, when the heating is on, I could bleed it daily and get lots of air out.
If I don't bleed the system while in use for a week or two, we frequently hear the air moving around through a couple of specific radiators.
I wish there was a facility to upload videos, I could show you how much air is coming out of one specific radiator.
I might order an aladdin autovent and put it on that specific radiator…..see what happens then?
Again thanks to all for your help, Im determined to get to the bottom of this!
Obviously, could be wrong, but if air is being injested for whatever reason then I would expect the pressure to rise and would expect it to read higher with either a cold or hot system, assuming no water loss. If air ONLY can then be vented then I would expect the system pressures to return to normal, this is what the Aladdin rad vent apparently achieves, when a number of "paper washers" are dry then it vents and when wet the venting stops, I suppose the ordinary float operated AAV achieves the same, when the float falls, air is vented, when it rises, float rises, venting stops,
I might order an aladdin autovent and put it on that specific radiator…..see what happens then?
Try that, but install it on the opposite (blanked) side of the rad and leave the rad vent as is.
Do you notice any rise in the EV pressure when this air is building up?.
Cant't remember if I asked but is there any "plastic" non barrier piping in the system.
Try that, but install it on the opposite (blanked) side of the rad and leave the rad vent as is.
Do you notice any rise in the EV pressure when this air is building up?.
Cant't remember if I asked but is there any "plastic" non barrier piping in the system.
Hi John,sorry, yes you did ask about plastic - no theres none on the system.
Im going to order an aladdin vent, cant do any harm surely!
Not sure if the system pressure is going up and down …..all I check is that the pressure stays the same and it does. Our house sits on small walls so that you can get under the floor….whenever we have to be under the floor for any reason, I always look at the radiator pipework underneath and never the slightest hint of a leak.
I so wish I could upload a video…I could let everyone see how much air is ejected when I bleed the system!
Im going to order an aladdin vent, cant do any harm surely!
Not sure if the system pressure is going up and down …..all I check is that the pressure stays the same and it does. Our house sits on small walls so that you can get under the floor….whenever we have to be under the floor for any reason, I always look at the radiator pipework underneath and never the slightest hint of a leak.
I so wish I could upload a video…I could let everyone see how much air is ejected when I bleed the system!
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