Potterton Flamingo on Y plan. System drain issues today.

[armyash]

On the job today (see previous thread about Y plan pipe configuration with pics). I stuck a hose on the drain valve down stairs, stopcock turned off and proceeded to drain the system. All was going fine, upstairs bleed valves opened and water draining fine. When it came to downstairs for some reason the rads would not drain, I cracked the nut on the return at the boiler and instantly water started to appear. In the end I got rid of the hose and got the wet vac on the drain off and emptied the downstairs rads. Undone the nut on the return at the boiler again and still lots of water. Seemed I had no choice but had to go for the drain plug on the boiler. (Hate these types). Wet vac ready and removed the rest of the water, was a good 2 vacs full worth of water. Anyone have any idea why this occurred while draining down? Seems to me that an air lock in the system somewhere but it was driving me crazy, needless to say it was not a productive day when I add in the staring at the pipework in the airing cupboard for what felt like 2 hours straight as well as jumping in and out of the loft and tracing pipes to see what was what. grrrrrrrr. Any ideas or just bad luck?

 

[Leo21]

Were you trying to drain the rads fom the boiler?

 

[armyash]

No, all from the drain off on the downstairs rad.

 

[Leo21]

No, all from the drain off on the downstairs rad.

Did the washer stick in the drain off ? The washer retainer in the mt plug can pull through the washer, meaning there's not enough flow for to drain properly. Or it was bad luck.

 

[armyash]

Did the washer stick in the drain off ? The washer retainer in the mt plug can pull through the washer, meaning there's not enough flow for to drain properly. Or it was bad luck.

Had that fully out to check, no problem. When I started to drain the system the water was flowing out the hose just fine but then just stopped. Will put it down to bad luck.