Help Airlock Rayburn System

Motorhomer · Post by **Motorhomer** » Thu Apr 08, 2021 7:30 am

I have a Rayburn connected to hot water cylinder indirect with radiators which turn on when at certain temperature. The system has been working for many years with no issues, but when I drain the system I get an air lock which sometime sorts itself out when the temperature gets to 90 deg.

I have drain the system yesterday to install a second radiator but this time the air lock will not budge. The radiators are turned on, I have tried running the rump continuously. At present the radiators do get hot but this also now blows into the header tank. I think the air lock is with in the cylinder coil and due to this the pump is back feeding the wrong way to the injector T.

Attached is a diagram, I was thinking would it be a good idea to put a gate valve 28mm where the pink star is on the diagram to close off when filling up. This should hopefully force the water through the cylinder coil and then open when full. Would this reduce the likely hood of an air lock.

Razor · Post by **Razor** » Thu Apr 08, 2021 7:33 am

Wouldn't you be far better off fitting an air bleed at the top of the coil pipework

Motorhomer · Post by **Motorhomer** » Thu Apr 08, 2021 7:43 am

Razor wrote: ↑Thu Apr 08, 2021 7:33 am Wouldn't you be far better off fitting an air bleed at the top of the coil pipework

Hi Razor. I could do this, but the overflow pipe which is 22mm to the expansion tank is at this point, would this not act as an air bleed

Razor · Post by **Razor** » Thu Apr 08, 2021 7:50 am

Yes it should do but then you wouldn't be getting airlocks. It's more likely you have a partial blockage at the fill point or the pipework from the top of the cylinder coil goes up then down again before the vent

Motorhomer · Post by **Motorhomer** » Thu Apr 08, 2021 8:06 am

Razor wrote: ↑Thu Apr 08, 2021 7:50 am Yes it should do but then you wouldn't be getting airlocks. It's more likely you have a partial blockage at the fill point or the pipework from the top of the cylinder coil goes up then down again before the vent

Air vent is straight from the top cylinder outlet. Should not have any blockage on fill pipe as it has just been refilled but might drain it again and refill just to be sure.
I was thinking if the fill went to the bottom rayburn first due to gravity, then filled up to the air vent it will leave an airlock within the cylinder which cannot be moved as its all gravity run
I have redrawn the diagram as it was slightly wrong hot from Rayburn should be connected to bottom of the cylinder but this should not change anything with respect to air lock

: rayburn2.png (29.88 KiB) Viewed 1342 times

Motorhomer · Post by **Motorhomer** » Thu Apr 08, 2021 11:38 am

Just done drain and refill and got water temperature up, this time it cleared the air lock at about 80 deg and is running all ok. When filling I isolated the radiators then filled up and once filled took two buckets out of the drain connection bottom of Rayburn which allowed some air lock to move. Bit fiddley but its working ok now.