3 Radiators Not Working

[cactus]

Possibly pump head (pressure) too low. If still no flow, leave only one rad opened up, if flow established, shut this rad off and go to next one until all OK. If you have a external pump post a close up view of it. If you have a sealed system ensure boiler pressure not < 1bar when cold, if open vented ensure small (feed & expansion) tank in attic "full" of water.

I am getting flow in most rads, two upstairs rads on one leg heat up nearly just fine, there are 3 downstairs that barely get warm and the other upstairs ones are pretty warm if all the others shut off, but barely warm if they're all open. I feel that perhaps I've got a block in a pipe, judging what's been going on. I can feel BIG cold spots in the downstairs rads, so I'm going to pull them off, blast them through with water to remove the sludge, chuck in some x400/x800 (Whatever is best) and then run the system to see if that improves, if not, I was planning on hiring a Norstrom proflush to flush the system.

 

[John.g]

Just prior to removing the rads you might consider (with boiler shut down) shutting off the valves on one of the downstairs rads, remove the vent complete or if installed, the plug at the other end, open one isol valve fully and let the water flow into a container for say exactly 10 secs (but no longer than 30 secs) and measure this amount, shut off this valve and repeat with the other valve open and compare measurements, before commencing each test, top up boiler pressure to exactly 2 bar, this test may show if the problem is either a blocked flow or a blocked return, but not guaranteed if the bottom of the rad is full of sludge. If a open vented system test time can be 30 secs or so.

 

[cactus]

Just prior to removing the rads you might consider (with boiler shut down) shutting off the valves on one of the downstairs rads, remove the vent complete or if installed, the plug at the other end, open one isol valve fully and let the water flow into a container for say exactly 10 secs (but no longer than 30 secs) and measure this amount, shut off this valve and repeat with the other valve open and compare measurements, before commencing each test, top up boiler pressure to exactly 2 bar, this test may show if the problem is either a blocked flow or a blocked return, but not guaranteed if the bottom of the rad is full of sludge. If a open vented system test time can be 30 secs or so.

I want to say it's the flow. I followed a plumber parts video to remove an airlock. It gurgled and BLACK water came out. I also felt some warmth, but after re-pressurizing the system and opening the lockshield, the rad went cool quite quick, which makes me think the flow is at fault. The hall rad is getting hot to the touch, its now just the dining room, which is getting slightly warm, but just barley, and the near cold living room. I've put in some x400 as I'm going away tomorrow, so I'll see how or if that helps remove anything, who knows.