System drain down

[novicegas]

Hi, Posted earlier however have discovered another problem. Refilled my open vent system, which took a long time, put the ch heating on and everything seemed to be fine, have since discovered that the top two radiators are completely cold whilst all other 7 rads are piping hot. All radiators are completely full and have been bled.

Any ideas??

Cheers

 

[diamondgas]

Turn the one's that are working off!

That should push any potential air locks out IMO

 

[clarky101]

Air lock....do as above post says...

 

[marleyco]

As diamondgas said, its often better to have heating and hot water running as you bleed, as the pump pushes the air out. Sometimes a real pain, you might also have to do it again after a few days as any pockets of air will find their way to top of system.

 

[novicegas]

Cheers guys,

Did this this morning, turned off the ones I could and the two radiators that were cold then began heating up. Unfortunately two of the rad valves began leaking quite badly. They're all very old ones, so I decided to change them.

Drain down then refilled, this time I had isolated all the rads I could, 5 out of the nine, as I didnt want to lose the inhibitor I added yesterday. Then refilled with the CH on. I now have all the radiators upstairs working and three downstairs not at all. Is it the same procedure of isolating rads and letting the pump get rid of the lock? Also on the refill, heard the boiler aav working i think but is there another one in the pump upstairs, pump making more sound than usual. Any ideas?

Many thanks

 

[clarky101]

Yep do the same, shut off the ones that work & push it to the ones that dont, and one by one shut them down when it goes down the return. Pump will push the air to a rad probably top floor so you can vent in time...

 

[PLUMB-KING]

When trying to balance heat in a heating system leave the flow valve fully open on the rads that are working but turn down the return valve till almost closed,this in affect will restrict the heat returning to the boiler to quickly, allowing the heat to flow more to other rads that are not working ( flow valve being the hotest pipe to the rad ) also I don't recommend venting/bleeding a system while the pump/circulator is running as the pump/circulator can create a little air itself while while running.

 

[PlumbBobBob]

i agree you only have to turn one side of rad down/almost off when balancing