Draining radiators/central heating system

[Craig89]

Hello all

I am coming to the end of plumbing my property but I have a question regarding the draining of the radiators/central heating system.

All of my downstairs radiators are fed with a flow and return that drop down from the ceiling (pretty standard I'm sure for many heating systems that have been installed in period properties over the years, especially those with solid floors). If I install a drain that goes outside lower than all the radiators will it drain the entire system by some sort of siphon effect or will water still be stuck in all the downstairs radiators and pipework?

The alternative is to fit a drain at each of the downstairs radiators, which I'm not against doing, but if one on the outside will work then that would be a nicer solution.

Thanks, Craig

 

[paulc]

You will need to fit a drain to each "drop". So if you have three sets of pipes running down the wall, that means three separate drains.
There are radiator valves available that have a drain off built in - This may be an alternative, but there would still be a bit of water left in the pipes as the valves wouldn't be at the lowest point.

 

[Feltwell]

I've got much the same setup, and agree, each "drop loop" down has to be drained individually.

What I've got, which works well for me, is a radiator opposite the downstairs loo with a drain cock teeing off at the lowest point - a short length of hose on this feeding into the loo pan works a treat to drain most of the system down, just leaving the final bit to be drained into a container, and then the other radiators individually. Very rare that I need to drain the whole system though, and if I do airlocks can be a pain.

 

[Bogart]

All above is good advice. Whenever I change a radiator I now install a lockshield that has a drain valve in it. Some are a bit ugly but I use Myson ones as they look neat and compact.

 

[Craig89]

Thanks all for the replies and advice. I will fit one in the pipes for each of the drops.

Cheers, Craig

 

[Owain]

You can drain an individual radiator by syphonage (very slowly) if you unscrew the bleed plug at the top, and put in a length of narrow tubing (eg earth sleeving) dropped down to a bucket. Rather more rapidly if you use a wet-and-dry vac cleaner to suck.