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[Sir Tigger KC]

I've got air in my heating system and it's driving me nuts!!    I regularly go round and bleed the rads but within a few days I get that 'whoosh' sound of air in the pipes!    I've had a good look around and nipped up a few joints here and there but I can't find any leaks..... 

So I was thinking about installing an automatic bleed valve on the rad that seems to suffer the most and was wondering if anyone here has used them?  Will one be enough or should I fit them to all the rads? 

The other thought I had was putting a bottle of leak sealer in the system, but I'm wondering if that might harm/clog up the boiler in any way?   

http://www.ebay.co.uk/itm/Aladdin-Autovent-Radiator-HV30-self-bleed-valve-Automatic-Chrome-Autovent-/111282535563?pt=UK_DIY_Materials_Plumbing_MJ&var=&hash=item19e8f4bc8b

[martin42]

1 what type of central heating system,combi or normal boiler
2 under no circumstances use an automatic air vent on a radiator
3 bleed air when heating is completely turned of including the hot water if a conventional system and start at the furthest rad away from the boiler on ground floor,then the other rads on groundfloor,then same again on the 1st floor,starting at the furthest 1 away.

[Taxi_Driver]

I had that problem....in a newly installed central system...in a house i once owned....every few weeks i had to bleed the rads....never found a leak....but air was getting in somewhere....never found the problem....i sold the house....sorry doesnt help....but you aint the first this has happened too....wonder if the new owners found he problem 

[Olympia5776]

I had a problem on mine late last summer where it was blowing over , filling up the expansion tank and overflowing out of drain. I inspected the auto drain valve and found it had seized solid and was inoperable .On the advice of a plumber I knew I was told to remove the auto air bleeder as " they're no effin' good " .A new pump was fitted as the old speed control self destructed when I checked it's operation  I went through weeks of having to reset the boiler after it tripped out on high temp . and after pressure testing and then dismantling the system and checking for blockages , silt etc . I returned the system to original spec. refitted a new auto bleed valve on the flow out of the ( oil ) boiler and left it open to atmosphere continually . Problem solved  and system has been  operating perfectly since .
I was also getting the air flowing up the expansion pipe to tank and it startled us a few times ....

[Andy H]

There are 3 causes of air building up in a wet heating system (once the filling and bleeding is completed)
- air sucked in due to poor system design or installation.
- gas released from fresh water introduced to the system (ie there is a leak)
- gas released due to corrosion or electrolysis

I know nothing about your system so can't comment on the installation.

If you have a header tank with a ball valve try turning it off for a week (to check for a leak)

Add a bottle of corrosion inhibitor to minimise corrosion.
 

[Taxi_Driver]

There are 3 causes of air building up in a wet heating system (once the filling and bleeding is completed)
- air sucked in due to poor system design or installation.
- gas released from fresh water introduced to the system (ie there is a leak)
- gas released due to corrosion or electrolysis

I know nothing about your system so can't comment on the installation.

If you have a header tank with a ball valve try turning it off for a week (to check for a leak)

Add a bottle of corrosion inhibitor to minimise corrosion.

I'd go for that in my old house....the plumber was cr*p....first time i had a bath the waste water emptied over the bathroom floor 

[Kevin Wood]

I am having a bit of a battle with this myself at the moment. I've already found a couple of old TRVs that had gone slightly leaky. Nothing of any concern leaking out of them, but found they would draw air in in certain positions. I suspect I've still got something leaking, as one radiator still needs a bleed every so often. System has had a very good dose of inhibitor. I was quite surprised that air can get into a sealed system that's running at up to 2 bar, I musty admit.

[Sir Tigger KC]

I've actually got 2 heating systems in mind, one of each type. 

2 under no circumstances use an automatic air vent on a radiator

Why?    What's the problem with them? 

[Olympia5776]

There are 3 causes of air building up in a wet heating system (once the filling and bleeding is completed)
- air sucked in due to poor system design or installation.
- gas released from fresh water introduced to the system (ie there is a leak)
- gas released due to corrosion or electrolysis

I know nothing about your system so can't comment on the installation.

If you have a header tank with a ball valve try turning it off for a week (to check for a leak)

Add a bottle of corrosion inhibitor to minimise corrosion.

I'm fairly sure the cause was down to the boiler boiling the water due to the operational set point on the boiler thermostat having failed and going OC .I should have said that I replaced that too. The Boiler 'stats have two selectable trip points , one at 90 and the other at 110 IIRC , mine was at 110 .
I have added two litres of Fernox since .
Good advice though as many forget to refill with corrosion inhibitor. 

[martin42]

I've actually got 2 heating systems in mind, one of each type. 

2 under no circumstances use an automatic air vent on a radiator

Why?    What's the problem with them? 

They can leak,need to rectify the problem,i would never fit 1 to a radiator,i never have in any of my central heating installs i did.

[omega3000]

There are 3 causes of air building up in a wet heating system (once the filling and bleeding is completed)
- air sucked in due to poor system design or installation.
- gas released from fresh water introduced to the system (ie there is a leak)
- gas released due to corrosion or electrolysis

I know nothing about your system so can't comment on the installation.

If you have a header tank with a ball valve try turning it off for a week (to check for a leak)

Add a bottle of corrosion inhibitor to minimise corrosion.

I'd go for that in my old house....the plumber was cr*p....first time i had a bath the waste water emptied over the bathroom floor 

 

I had the same , well someone had a bath and i felt drip drip on my head in the living room  The waste pipe was all loose + the sink water waste backs up into the shower 

[pscocoa]

For the op what is the set up in your airing cupboard? There  should be a bleed there - we just had to bleed a few times here to get rid of a bit of air following rad and pipework changes

[tidla]

Plumbers don't always check that the actual bleed screw and cap on the other side is tight on new radiators.