new air vent - how does it work? I got bubbles.

[JohnD]

there is a brass cylinder, about 20mm dia x 75mm high, with a little red screw cap on top - I am told it is an air vent - sorry my camera does not work - it is fitted on a riser from the primary feed to the cylinder.

I formerly had a vent there that I could unscrew with a bleed key, but it never got any air in it.

I ask because I sometimes get the noise of bubbles going through the boiler shortly after it starts. I have topped up the inhibitor and bled the rads and verified it is not pumping over.

I also have an alpha+ pump if that matters.

Pump, valve, three port and all controls were all new in Sept when the boiler was changed. Syst is very clean. Syst is Vitodens 100 Compact open vented with cylinder. I recently cleaned bacterial slime out of F&E and added fernox AF-10 to the clean F&E.

Inhibitor is sentinel X100 which is recommended with my Permutit Water softener

 

[cider]

You have a flamco auto air vent. What exactly is your problem?

 

[Jezclayton]

If the boiler was only changed in September, you should be on the phone to the installers and ask them to sort it out.

Most installers will give at least one years guarantee, if not two and good installers would want to know if you have a problem.

 

[JohnD]

Thanks, I found this image, it looks like the left-hand thing:

installer is not that good and brushed me off when I described the bubbles.

So, the air vent. Can I open it or anything to make sure it is working and there is not a pocket of air behind it? How does it work?

Or any idea what the cause might be? I am thinking maybe an air leak on the suction side of the pump at a compresion joint.

 

[gas4you]

The 'red knob' on the top must be 'loose' to enable it to work to expel any air.

Personally I don't like these, if I ever have problems with auto air vents, it is usually this type

 

[gassywind]

as long as your system is not pulling in air,the air already there should slowly leave the system BUT some systems have areas where air bubbles will collect and not vent through an aav or the vent.
the red cap on your aav needs to be open and sited correctly,test it by applying leak detecting fluid ok soapy washing liquid diluted with water with a small brush to area of red cap,turn on ch and hw watch for bubbles around aav,this is best done first start up in the morning.
keep trying it bubbles=working.
i have had similar air bubble noise faults and fitting the flamcovent (brass) on the flow pipe as close to boiler as possible.works 100%.
see flamco web site.
ps there are other air release valves available but i use these ones.

 

[JohnD]

as long as your system is not pulling in air, the air already there should slowly leave the system

that's what the installer said

but it's been doing it for 6 months

 

[D_Hailsham]

So, the air vent. Can I open it or anything to make sure it is working and there is not a pocket of air behind it? How does it work?

The Flamco AAV is in two parts, the joint is just above the hex nut. The bottom part is just a shut-off valve, which is open when the valve is assembled but closes when the upper part is removed - you can see the valve sticking out underneath. This means you can separate the upper (AAV) part from the rest without water flooding out of the CH system.

The upper, AAV part, can also be separated at the top brass cap. Inside you will find a float connected to the venting valve. When full of water the float rises and shuts of the valve. But if there is any air the float level will drop, opening the valve so letting the air out. The red cap should be open about one turn.

I would remove the upper part, disassemble it and check that the float is working properly. If it is in a poor condition you can buy a complete new valve, but only use the top part.

 

[Jezclayton]

installer is not that good and brushed me off when I described the bubbles.

Hopefully, you won't be recommending him to anyone else then.

It is always ironic that the poorest installers get away without doing any warranty work because the customers won't have them back.

I find little wrong with the Flamco vents and they are certainly better than many others the market. It does sound like your vent is working properly, the problem being that either air is being drawn in elsewhere, or you have corrosion taking place.

Have you measured the ph in your system? You mention you have a water softener. Does the system fill with artificially softened water, in which case it will be acidic?

 

[JohnD]

I have not measured the ph, but I put an extra litre of X100 in just in case (and drew it in) and Sentinel say X100 is suitable for softened water.

The gas does not ignite when I hold a match to the bleed valve, and I put a couple of steel nails in a sample jamjar, they are still bright.

I am thinking a suction leak on a compression joint. Any tips for finding it? As the water is clean and soft I doubt it will seal itself with scale.

 

[ChrisR]

Is it a sealed system John? If so, try it with the pressure higher, like 2.2 bar.
That'll often stop air being sucked in.
Imho Flamco vents are expensively made but work no better that the £2 variety.

 

[JohnD]

open vent

new pump, valves, boiler, controls, connections were done in September.

 

[Deleted member 105431]

flamco aav's are better than most that I find tbh. Add some fernox F4 to the system and check the feed and vent configuration is correct, that the pump is on the correct speed (usually 2) and not over rated (/50 or 5m head should suffice).

 

[Jezclayton]

Same here. Put some Fernox Leak Sealer in.