Problem with drain cock when trying to drain down CH system

[Tufty_b]

I added a sludge remover a few weeks ago and went to drain it out, however I had a couple of problems after I had attached a hose and undone the drain cock.
1) Water only dribbled out of the hose, I was thinking that the washer was stuck, but didn't dare undo the valve completely in case water gushed out all over the floor.
2) Water was dribbling on the outside of the hose!
3) Initially when I tried to tighten up the valve again, water was squirting out of the drain cock. After pondering what to do for a min or two I realised that my only option was to ride it out and tighten up the drain cock and hope the water stopped. Luckily the water spurting stopped.

My question is, what is wrong with the drain cock and how do I fix it.

 

[Gasman1015]

The washer is stuck in position, it will need dismantling, either freeze the pipe or drain off using the smallest rad you have, on the same level.

Shut both valves on the rad, undo the valve to rad connector and drain radiator into plastic dish , box or whatever and empty into bucket, open air vent to release water slowly until empty.
Then remove radiator, fit connector with copper tail, fit hose pipe and open valve to drain system.

 

[ChrisR]

Tip - normal 3/4 garden hose connector usually goes straight onto a rad union.

It isn't too bad to "snatch" drain cocks like yours. Helps a lot is you have a vac which can take water. Helps if there are two people too, sometimes!

Start with NO air vents open, and bung the f/e tank connections with rubber bungs, or a speedfit connector on the vent and a ball of plumbers mait in the tank on the outlet.
Basically get a well fitting hose on the drain cock. Undo the whole of the head and water will come out, but you can put your thumb on it so the water only goes down the hose. It will slow down honest! Then get a big screw like a coach bolt, say 8mm diameter, and shove it up past your thumb. Screw it in a bit and it'll pull all or most of the washer out.
If the bungs are working you won't lose all that much water. If you use the DC to let the first water out, it'll pretty much stop.

 

[Tufty_b]

Thank you very much.
Excellant quick responses from both of you.

I don't have the option of draining off the smallest rad on the same level because the 3 rads on the ground floor are each separately fed off pipes from the 1st floor and I don't fancy having to do this on all 3 rads if it turns out all of them are in the same state.

I think that I probably try and snatch the drain cock(s) as this will be the quickest and cheapest option (assuming I don't end up dumping the CH water over the carpet).

 

[kevplumb]

get yourselt a reasnible sized root veg will come in handy if it does go t*ts up

 

[fitz1]

Get a builders bag without air holes in it and let water go into that whilst u try to hook the washer out of the drain off.

 

[ManxPlumber]

Did you depressurise the CH system before opening the drain valve?

...1 to 1.2bar system pressure would normally shift a sticky washer ~ that's 10 to 12m head of water