Refilling Sealed System

[Mrast]

Hi,

Just a quicky - my combi system has been drained, filled, drained, filled multiple times for whatever reasons over the last month or so...

Im fed up of chasing airlocks - and i seem to get the most stubborn ones!


Whats the best practice when i fill the system from empty?

Is it best to have all TRV's and Lockshields open on all rads upstairs and downstairs?

Or Close all LS and TRV valves upstairs, fill downstairs and then go open upstairs hopefully draggin any trapped air up with it and being able to bleed out from upstairs?

Thanks

 

[nysk2008]

just open em all up, fill to around 1-1.5 bar (remember to add inhibitor before), bleed all rads (the pressure will then reduce) top back up - once all rads are bled pressure should be in the 1 - 1.5 bar area from cold

 

[Simon F]

if you are getting air locks it is because the pipework is not level,
apart from changing it, all you can do is fill up then have the system running and send it through one radiator at a time to force any air around and into the radiators where it can then be bled.

 

[Mrast]

if you are getting air locks it is because the pipework is not level,
apart from changing it, all you can do is fill up then have the system running and send it through one radiator at a time to force any air around and into the radiators where it can then be bled.

Would this be achieved by closing all rads completely then opening both TRV and LS on each rad as i go working my way upstairs?
And i do this with the thermostat on calling for heat yes?

 

[Simon F]

if you close the lock shields, then you might have to rebalance the whole house after??
have all trv's open to max, fill the system, turn it on, if any radiators are struggling then close some/all of the other trv's to force the air out of that one. Do this one at a time for any problem rads.

 

[nysk2008]

sealed system surely after bleeding the system, refilling and then bleeding air locks should be a thing of the past?

 

[happyflyer]

The main problem filling a sealed system is you need your Doris on the fill loop, topping it up as you bleed, easy way is to fit a £25.00 PRV just after the loop, set at the cold charge pressure, you can wander around the house venting at your leisure. Like Simon says don't mess with the LS valves, BTW do not try venting any system with the pump running thinking it might help, it may well move the air around when you have most of the air out and the pressure up, this air should end up in the tops of rads.

Now you may have another problem, if you have a Worcester boiler and this may be on other boilers there is a vent inside the boiler case, this will need to be vented, if you are not GSR you can't take the case off, silly boiler designers hey.

 

[Mrast]

The main problem filling a sealed system is you need your Doris on the fill loop, topping it up as you bleed, easy way is to fit a £25.00 PRV just after the loop, set at the cold charge pressure, you can wander around the house venting at your leisure. Like Simon says don't mess with the LS valves, BTW do not try venting any system with the pump running thinking it might help, it may well move the air around when you have most of the air out and the pressure up, this air should end up in the tops of rads.

Now you may have another problem, if you have a Worcester boiler and this may be on other boilers there is a vent inside the boiler case, this will need to be vented, if you are not GSR you can't take the case off, silly boiler designers hey.

In it together these manufacturers and the GSR guys i tell thee

My boiler has an "auto air vent" - a tyre valve cap on top of the pump - i know this is open sufficiently as the guy who serviced my boiler last autumn opened it up by 2 turns as apparently it was shut.

I tend to fill - vent (actually vent when i get back downstairs and the boiler pressure back to 0) - fill again - bleed again (vent again when back at 0) - all the while the mrs is moaning shes cold.

Life huh

 

[stevetheplumber]

if your getting airlocks on a mains fill system something is very wrong even up and over loops fill from mains pressure