Draining the central heating when there is no Drain valve ??

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Hi all,
My Radiator is leaking. From what I can see I need to replace the valve.
To do this I need to drain the system.
Everywhere that I have read refers to a draining valve that should exist on the lowest radiator in the system.
I need to connect a hose to this and drain.
However None of my Radiators have a drain Valve so How do I drain the system ????

I have managed to remove the radiator in question but the problem is with the valve connected AFTER the radiator that needs to be chaged..


Another quick question is - Do all radiators come with a seperate tail? Or do old Radiators have the Tails built onto the Rad.
I think the tail on another radiator is leaking but it looks like it is part of the Radiator as there is no bolt on it for removing from the radiator.

Thanks for any help,
Ray..
 
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My previous house had no drain valves on,

So I turned off a radiator completely and removed it and tipped the contents out into a large bucket (sounds like you've done this part already)

I then made up a bit of plumbing out of some spare bits to connect up to one of the valves which are left on the pipes where the radiator came from. I then connected this to a bit of hose which I ran out of the door into the drain.

I then opened the valve back up again and the system drained out.

Once drained I replaced the valves with valves which had integral drains in them, and replaced the other end with thermostatic valves.

Hope that helps. No idea if it's the right way to do it as I'm no pro, but it worked for me ;)
 
Brilliant idea mate..

Thats right I have had the radiator off before.
Now if I connect a hose to the Closed valve.
Leave all the other radiators open.
Then open the valve. the system should drain out anything thats connected after this Radiator ?

Do you know anything about the tail part of the rads?
I know this is leaking but don't want to have to get a whole new rad if the only prob is the tail.usually the tail has a nut on it for you to remove it from the Rad but mine doesn't so I'm wondering if this is an Old rad that has the Tail encorported into the radiator ?

Ray..
 
Is your ch system combi that is sealed/unvented or does it have a feed and expansion header tank vented????

If vented dont forget to turn off the stop cock or tie up the ballvalve in the header tank... or draining down will take an infinately long long time.

turn valves off
roll back carpet put some old cloths/towels down
loosen nut where rad valve attaches to radiator
remove radiator if small, if long, heavy, large you'll need an extra pair of hands
invert rad (turn upside down), take outside and drain off
a wash mac hose should attach to a rad valve
get 2 buckets and open up the valve drain off thru hose
get a 15mm equal compression tee coupling and a drain off cock with a long shank
at lowest point on system (great if you have a cellar and acces to pipe runs) cut out 15mm off tube and fix t fitting and then fix doc to t section off coupling (you'll need a 24mm spanner or adjustable wrench).

2nd question. Some valves come supplied with a short section of copper tube as the fitting of the tail to the valve utilises a brass flange and rubber washer. These are quite old fashioned and your new valve is more likely to utilise an olive compression fitting. The most likely indication of this is if there is an end feed or yorkshire soldered coupler, on a tail, approx 4" underneath the pre-existing valve. If this is the case you will have to reinstate a short section of tube. If you have the required stuff to solder, then solder therwise a compression fitting will be required.

Hey presto!!! new valve installed and doc fitted.

Dont forget to refill system with inhibitor... If water is gungey black or rusty then add sludge remover run system fer prescribed, alloted or recommended time.
Drain down again flush thru with clean water a couple of times
add inhibitor and refill/bleed system.
 
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oh yeah, silly me, you can get a valve that incorporates a doc. but to change this you will still have to partially (if upstairs) or completely drain down the system (if downstairs) So you'll still have to add inhibitor.

the old valve should be able to attach to a blank or bleed cap on the top of your rad. If you leave a short section of tube on the valve then utilising a plastic funnel you'll be able to pour the inhibitor in. If vented system just pour bottle into f&e tank.
 
Hi there,

Just thought i would throw this in but when i was changing rad in my house the plumber who was helping me just tied up teh ball cock in the expansion tank and then opened up the drain valve on the side of the oil boiler.

Obviously my boier is outside in a boiler house and all the water just drained out of a hole at the bottom of teh side wall of teh boiler house. Dont know if your on gas or oil or what but just thought i would throw that in.

Then flushe dteh system by untying the ballcock, re filled teh system with fernox and away you go.

Sean
 
A couple of points:

1 - I fitted a cheapo drain cock from the local DIY store at a low point in my system. This has a very tiny rubber tap washer inside it, which collapses very easily if overtightened. When I undid it to partially drain the system some months later it wouldn't stop dripping as it had collapsed. So I bought a new one and simply replaced the core with rubber washer.

2 - I was able to do this without fully draining the system by draining down a couple of feet below the header tank then inserting a gate valve into the CH supply pipe. I refilled the tank then closed this valve and blocked the expansion pipe (by temporarily fitting a second gate valve on the end). By closing both valves I can now work on the heating system by draining where I want to work and, when the water stops flowing, allowing the water to "hang" supported by the vacuum above. You need to move fast and have towels handy.

This worked fine a second time I did work. But: I re-closed the aforementioned cheapo draincock and went off for supper. The heating came on and an hour later when I went for a tinkle I found the downstairs bathroom awash with very hot water, which was pouring out of the cheapo drain cock. The tiny tap washer had collapsed again and when it got hot, had failed completely allowing hot water to pour out.

So I found a proper tap washer made of good hard rubber, cut it carefully to size with a sharp knife and installed it on the tit inside the drain cock. No more problems, I hope......!
 
self cutting drain cock or washing machine connection. when done just cut out holed section - add tee and drain cock. bosh.
 
Sometime the drain offs can be on the outside, sticking through the outside wall.
 
When you drain open the rad vents at the highest point or you could get an air lock and as you are working on the rad pipe a gushing of water too ;)
 

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