draining ch system but have 2 drain cocks?

[totterfield]

I have an old oil fired ch heating gravity fed system with expansion tank in loft, my question is when draining the system to clean out , flush and inhibit I have 2 drain cocoa outs on the patio, are they both the central heating? If so do I need to drain in a certain patter or procedure to get the water to flush through the radiators?
Any light shed would be appreciated
Thanks
Tom

 

[totterfield]

I have an old oil fired ch heating gravity fed system with expansion tank in loft, my question is when draining the system to clean out , flush and inhibit I have 2 drain cocks outs on the patio, are they both the central heating? If so do I need to drain in a certain patter or procedure to get the water to flush through the radiators?
Any light shed would be appreciated
Thanks
Tom

 

[Burnerman]

The flushing water will only find the easiest route through the system.....would you consider taking each radiator off and flushing it with a hose outside?
John

 

[totterfield]

Hmmmm, I don't think they really need emptying, I'm only doing this as I'm replacing 2 radiators for towel rails, the radiator do warm up well with no obvious cool spots. Was most curious about the fact I have 2 drain valves?

 

[Burnerman]

Who knows about that one, but they certainly will be handy if you want to drain down!
Maybe one is the C/H lowest point, and the other from the copper hot water cylinder?
John

 

[totterfield]

That would make sence but just had a look And there is a drain cock at the bottom of the hot water cylinder feed. Who knows, maybe one side is the end of the hot loop an the other the end of the return loop.??? Mystery

 

[CombustionGuy]

Drain on flow pipe and drain on return pipe.

 

[totterfield]

Drain on flow pipe and drain on return pipe.

Ahh, so If I wanted to drain the system and get the flow going through the radiators how would I do that, could I close down all bit one radiator at a time and drain through the hot flow pipe?

Ie would it just come straight through from expansion tank missing the radiators?

 

[kbdiy]

I fitted my system with a drain cock on each side - flow and return - just makes life easier for a faster drain down and backflush if necessary.