Air in the open vented system

[Inverness]

Open vented system with a gas back boiler. The upstair radiators are hot a part from two are cold. There is still air trapped in the system. I've flushed it out several times even by capping off the f&e vent pipe and attaching a hose to the drain valve to disturb the built up of sludge and I've filled the header tank with system cleaner and bled all the bottom radiators then the upstairs now only two that are upstairs are filled but cold? I'm going back in a few weeks later to flush the system out and hopefully it was only a build up of corrosion in the pipe work.

The two cold radiators up the stairs have been manually flushed out and new trv valves been replaced.

There is a aav in the loft, could this be sucking air in? Maybe replace for a new one?

I'm kneeling for your knowledge and expertise would be more than appreciate?

 

[Ch4 plumbing]

Okay, so we can assume that you have turned off all the rads except one of the non working ones to see if you can clear air from the pipe work?

are the new TRVs multi directional?

if no have you checked that they are on the flow?

 

[Inverness]

Okay, so we can assume that you have turned off all the rads except one of the non working ones to see if you can clear air from the pipe work?

are the new TRVs multi directional?

if no have you checked that they are on the flow?[/QUO

Thanks for your response.

yeah I have and the trv s are multi directional.
the two radiators do drain down and fill back up so no problem with the flow.maybe the return?.

 

[Ch4 plumbing]

Okay, try shutting the valves off and removing the rad.
connect a hose to the return and flush the return to see if it's clear.

Remember to turn the boiler and pump off first.

Have you opened the bypass valve on the system?
if yes you need to close it and open it again a couple of turns.

 

[Inverness]

Okay, try shutting the valves off and removing the rad.
connect a hose to the return and flush the return to see if it's clear.

Remember to turn the boiler and pump off first.

Have you you opened the bypass valve on the system?

Yeah I've done that too. That will be my next task to try and do. I was hoping not to do that but I guess that's all I can do.

thanks everyone

 

[turnpin]

Did you manually open the motorised valves when draining down and when refilling?...regards Turnpin:8:

 

[Inverness]

I'll try opening the motorised valves today and see if that helps.
thanks for your time and magic!

 

[spanner]

The system seems to be in need of a full on flush to get all the silt ferr and oxide out...

 

[Ermintrude]

X400 for two weeks on full power then drain down and refill. Drain down from as close to the boiler as poss. (Sometimes) drain off below pump in cupboard in side I chimney. Also drain it when it's hot.