Rad advice please

[phil1963]

I have just had my radiator sytem bled, an erroneous rad corrected and now it is full with clean water and anti-grunge liquid and has worked fine since. However after 3 weeks one of the radiators upstairs needed bleeding. It took about 5 seconds for all of the air to come out ..............
1) how often do rads needing bleeding on average
2) what would happen if I was away for a while and the whole radiator clogged up with air ........ would the air go down the pipes and cause the next rad to fill with air
3) how do I find the cause of air getting into the system.

 

[Softus]

I have just had my radiator sytem bled, an erroneous rad corrected and now it is full with clean water and anti-grunge liquid and has worked fine since.

Since when, exactly?

However after 3 weeks one of the radiators upstairs needed bleeding. It took about 5 seconds for all of the air to come out ..............
1) how often do rads needing bleeding on average

On a clean system, almost never. Annually would be acceptable.

2) what would happen if I was away for a while and the whole radiator clogged up with air

If the system is protected then this is unlikely to happen, unless you go away for about 18 years.

........ would the air go down the pipes and cause the next rad to fill with air

No.

3) how do I find the cause of air getting into the system.

Bit of a perennial problem is this - it's usually best to eliminate the things that might cause it, first, then move on to a search for a leak if all else fails.

Please describe the history of maintenance to the system - when it was last cleaned out, when inhibitor was added, when any pipework was changed, when the boiler was installed, etc.

 

[Timmyturtle]

If a rad has recently been changed there could have still been some air in the system from when this procedure was carried out.

 

[TicklyT]

I would expect a bit of air to accumulate somewhere after 3 weeks. The new water in the system will always contain some dissolved gases which will be driven out of solution slowly. If all is well, the next time a rad needs bleeding will be a bit longer, say, a couple of months, then six months etc. etc.

 

[phil1963]

The system was flushed out and replaced with nice water 3 weeks ago. I works okay except for this one heater which has "aired up" quickly - hence my concern.