Air in central heating

[Pip89]

Hi everyone

Just over a week ago, we had some new radiators installed, plumber drained system, installed radiators, added Fernox F1, and refilled the system. A few days prior to the work, I added Fernox F3, which was flushed out when the system was drained.

Since the new radiators we’ve been getting a lot of air in the system. The highest towel radiator has been bled a few times, the Wilo pump has got nosier, the AAVs vent air a lot more (one leaking one bubbles out).

We have a gravity fed system, with an F&E tank in the loft above the hot water tank, and a combined 22ml cold feed. I’ve checked the tank water level and it’s fine. I’ve turned pump down to setting “2”.

Any idea what the problem could be?

Thank you
Rob

 

[Johntheo5]

Thats setting isn't setting 2 if its a (6M) Wilo Yonos Pico, like my (5 year old) own, it looks as if its on a very low PP setting and will pump practically nothing at that setting but still shouldn't cause those problems, suggest turning the control to position 2 (12 oclock) which should show C2 when you select it, on my system, if I selected that setting it would run at ~ 22W, this is a fixed speed 3.8M fixed speed setting, problem might be "chemically" related, you may have to drain the whole system down again and flush it out at least a few times, then suggest refilling without any inhibitor, get rid of any air and the (re) add inhibitor slowly by draining a few litres from any rad through its vent/bleed and then adding the inhibitor. Bleed air with boiler/pump off.

Where does the cold feed tee into you system?.

Just read your Vaillant error code thread. I think your pump shows the flowrate in m3/hr and the head in M so note these two after c/o to fixed speed 2.
There's also another setting on your pump to "get rid" of air, just keep that white button pressed for ~ 5 secs, the pump then speeds up slows down and maybe even stops briefly over a 10 minute period, I've never used it, probably does very little IMO.

 

[oldbuffer]

1. Air can take quite a while to come out of the system.
2. Turn boiler off and allow system to cool.
3. Manually open both motorised valves (S plan) or set motorised valve to mid-position (Y plan).
4. Bleed all radiators. I do downstairs first then upstairs on the basis that air rises through water.
5. Bleed any air from the hot water cylinder coil. There may be an AAV or manual bleed screw on the uppermost connection to the coil. If not carefully slacken a compression joint onto that connection, but avoid touching the connection where it actually goes into the cylinder.
6. Run the system
7. Repeat a couple of times if necessary.

 

[Pip89]

Thanks so much, I was thinking I might need to re-drain. I’ve adjusted the pump to 12 o clock and it runs at 20w/0.4m. I think it was on that before, but it was getting noisy (which goes away if a drain as all air).

The cold feed tees in about 150mm before the pump.

 

[Pip89]

1. Air can take quite a while to come out of the system.
2. Turn boiler off and allow system to cool.
3. Manually open both motorised valves (S plan) or set motorised valve to mid-position (Y plan).
4. Bleed all radiators. I do downstairs first then upstairs on the basis that air rises through water.
5. Bleed any air from the hot water cylinder coil. There may be an AAV or manual bleed screw on the uppermost connection to the coil. If not carefully slacken a compression joint onto that connection, but avoid touching the connection where it actually goes into the cylinder.
6. Run the system
7. Repeat a couple of times if necessary.

Thank you, I’ll give all of this a try after work.

 

[gas112]

Was it standard rads that were fitted or designer ones as air can take days to totally come out of some of the designer ones

 

[Pip89]

Was it standard rads that were fitted or designer ones as air can take days to totally come out of some of the designer ones

They’re designer ones (2 cast iron, 1 steel column). We’ve had all rads changed over the last 12 months and never taken this long for air to drain (though maybe I didn’t notice as the AAV wasn’t leaking before).

 

[gas112]

They’re designer ones (2 cast iron, 1 steel column). We’ve had all rads changed over the last 12 months and never taken this long for air to drain (though maybe I didn’t notice as the AAV wasn’t leaking before).

although i said a couple of days i have seen the odd ones take a couple of weeks the air just gets trapped in them a case of forcing it around system . Turn everything off apart from one or two of the new ones and see if it pushes it out

 

[Johntheo5]

You can do the above with max head combined with least noise by changing to CP mode because these pumps have almost infinite CP & PP settings (in 0.1m increments), turn the control to the houses to the right of C3, to CP mode, the selected head will flash each time you make a adjutment and then revert to displaying the flow and power.

 

[Pip89]

Thanks everyone, I’ll try this troubleshooting over the next few days

 

[wedge69]

If it's any help, it usually takes all winter for me to get the air out of my radiators after a drain down

Just gets stuck in one rad and have to wait for it to work it's way to the towel rail in the bathroom

 

[Pip89]

If it's any help, it usually takes all winter for me to get the air out of my radiators after a drain down

Just gets stuck in one rad and have to wait for it to work it's way to the towel rail in the bathroom

Thanks, that’s reassuring. The pump seems to have gone quiet again, still getting air from radiator, but hopefully it’s getting better