air in rads?!?!?!?!

[panda2006]

i have recently fitted some new rads to my system, replacing old singles with doubles, the system has been flushed a couple of times and clear water running through all of the system.
One problem i have is after the system ruuning for a few days when i bleed the double rads i have water coming out but there is also a hissing of air! do i need to keep bleeding until hissing has stopped? could it be one side of the rad is full of water but other still has air??

Also i added an extra rad on to the system teeing into 22mm pipe with 15 mm but this rad does not get hot the pipes don't even get hot is there a minimum distance the flow and return on a one pipe system has to be apart?
coul the return tee be too close to the flow tee? and how much 15mm pipe run can be made off the 22mm does that make any difference?

 

[JohnD]

Did you add a corrosion inhibitor when you refilled?

 

[panda2006]

No not yet, would this make a difference with the air??

 

[JohnD]

yes, every day you don't have inhibitor, the steel rads are getting more and more rusty, this creates gas.

Imagine throwing fresh unpainted steel plate into a bucket of water. that's your new rads.

 

[panda2006]

Ok, do I have to get the air out before or after the inhibitor is added to the system?

 

[JohnD]

add the inhibitor, after a day or so it should stop making gas, so you can give them a bleed to get the last stuff out. All being well it should then settle down.

You may like to consider using a chemical cleaner as well, and rinsing it out before you refill with inhibitor. It just means a bit more work with the hospipe.

 

[panda2006]

I have alredy used a chemical cleaner that I added to the system while I was on Holiday for a week.

Will adding the inhibitor solve my second problem with the extra radiator that I added that doesnt get warm at all when the heating is on??

 

[JohnD]

No, that's a different problem. Best to raise a new Topic, highlighting that it is an addition to a Single Pipe system in the "subject".

 

[gigz]

Did you bleed both panels of the rads