Fully draining radiators in my system, bit of advice needed.

[cmberry20]

I have a vented CH system in a small 3 bedroom house with 9 radiators.
When I bled my radiators over the winter the water that came out was VERY black. So during the nice weather, I decided to drain the system down & add some Sentinel X400 to get rid of any gunge that might have accumulated before draining again & adding some X100.

So, I attached a hose to the kitchen Rad that had the appropriate connector by the valve, switched off the water & opened the valve & waited for the water to drain. Once the water had mostly stopped coming out I then opened the bleed valves on the top floor Rads to allow the water to drain off a bit more. Once happy, I preceded to the ground floor radiators. This is where the problem lies...
None of the ground floor radiators (apart from the kitchen one with the hose attached) would drain. Water would still spurt out of the bleed valve when I opened it. Now, I believe this must be because each ground floor rad is fed from the top floor (pipes in the ceiling) straight down (pipes are chased into the wall) & then go straight back up again. This effectively forms a 'U' which stops the water from draining out to the kitchen Rad with the hose on it.
So, with the system half drained, I added the X400 to the CH header tank & refilled.
However, next month, I want to fully drain the system thus removing the X400 & grime & add some X100.
It seems that each downstairs radiator (not the kitchen one) has a drain valve which is built into the flow valve. However, this drain valve has a pin in it which is identical to the bleed pin found at the top of the radiators.
So, to drain each of the downstairs Rads, should I shut off the flow valve, remove the drain pin, and then reopen the flow valve thus releasing the water. (I’ll catch the water in a large bowl or something). Is this right?

Also, with the X400 currently in my CH system, is it a good idea to put the CH on each day for 30mins or so to allow the X400 to fully circulate? I’ve had it on a bit, but not more than 2 hours in the past week.

Any advice is always appreciated.

Cheers.

 

[SmithyXL]

From what you have said it would seem that every radiator downstairs has it own drain valve, its a bit of a pain but just connect your hose to each radiator one at a time and drain them off.
No need to shut down the flow valves, connect your hose nice and securely and let it go.

Running your system for a couple of hours each day would go a long to helping the X400 do its job.

 

[cmberry20]

The problem is that the drain pin is built into the nozzle. I cant undo it with a hose attached, so, i think i need to shut off the valve so that i can release/remove the pin, then open the valve once the hose has been attached.
Just thought it was a odd having this design of drain valve.

 

[tryitandsee]

Better then to take the radiator off the wall altogether and blast it with the hose outside. Take a bit of time etc draining it down with the risk of spoiling Mr or Mrs CMBerry20's carpet.

If full of black stuff, a good shake down out side is more satisfying. Also read the tin on x400, needs to run hot, not sure!