air in rad!!!!!!!!!!!

[panda2006]

hi have been having problems with my system i have recently replaced some of my old rads beacause i had a leaking one and some knackered old ones, i have a one pipe feed system and some of the older rads are not getting hot at all which i have narrowed down to prbably a blockedge , however the leaking one i had which has now been replaced with a new double keeps getting air in it and even after a bleed it does not get fully hot, it is only this rad which gets the air in would a blockage cause a rad to get air in?? or could i possibly have a leak that is drawing in air????

 

[semi-acoustic]

Hi

You did not say how recently you changed your rads, but remember you will inevitably get air in any system when you replace rads because you are filling up the system again.

When I have to refill my system, I do it very very slowly via the main stopvalve in the F and E tank, even then when the heating has been on for a week or more you may still be bleeding the radiator so just be patient and the air will hopefully clear in time.

Hope this helps.

 

[bab]

it really does depend on how the system is piped up. the rads that arnt getting hot my have a build up of sludge in them & need washing out when removed, you might be pumping over the f & e tank if the pumps on too fast causing ingress of oxygen. if one of ya rads leaked then sounds like an oxygen problem causing corrosion which is what the sludge is.

 

[panda2006]

i replaced the rads three days ago i have the pump speed on 3 beacause we are a ground floor bungalow with about a 40 meter run of pipe from the pump, Why is it always the same rad that gets air? and as for the rads that dont get hot the flow pipe is not even hot which would suggest water is not even getting to them??? i am planning to put some fernox restorer in for a couple of weeks injected straight into a rad would this clear a blockage???
my hot water is run by a separte pump to the heating the heating pipe runs straight from the pump underground to the rads.

any helpful advice appreciated!

thanks
karl

 

[semi-acoustic]

Hi again

You may need a power flush done on your system. this will clear any sludge, you can then add fernox once you know the system is running ok.

Either way let us all know how you get on.

 

[bab]

So your heatings a single pipe with gravity circs that have been pump assisted, sounds like a the hallmarks of pumping over & a shed load of iron oxide sludge. power flushing aint good on a one pipe ,you will need to remove old rads to wash out well then address the incorect pipework ?