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Draining oil fired central heating - downstairs radiators not draining

  • 15-09-2022 1:52pm
    Registered Users Posts: 680 ✭✭✭


    I'm currently draining my central heating system and have successfully drained all the upstairs radiators through a drain point by the boiler. However, the downstairs radiators are not draining so I assume that these are on a separate drop. If they are on a seperate drop is there anyway of identifying where a drain point for these could be (I can't find one) or would I need to drain each of these radiators individually?




  • Registered Users Posts: 680 ✭✭✭JazzyJ

  • Registered Users Posts: 5,428 ✭✭✭The Continental Op

    I'm just guessing here but you could have some form of air lock. Have you tried opening the air bleed valve in some of the downstairs rads? If they don't piss water out leave them open.

    Wake me up when it's all over.

  • Registered Users Posts: 680 ✭✭✭JazzyJ

    Tried the bleed valves alright, but pissing out water!

  • Registered Users Posts: 5,428 ✭✭✭The Continental Op

    OK so the water is above that height. OK so try the valves upstairs. I'd be trying to let air into the system as well as getting the water out. You could even separate a joint above the water level to see if that helps.

    Assume this is an open and not a closed system - there is a separate header tank for the heating system, thats empty?

    Wake me up when it's all over.

  • Registered Users Posts: 3,201 ✭✭✭cruizer101

    If they are on separate drop I would have thought there should be a drain off at one of the radiators.

    That said drain offs aren't always present. In my house just have to take a radiator off.

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  • Registered Users Posts: 12,571 ✭✭✭✭Dtp1979

    Your downstairs rads are probably fed from upstairs. A product of the boom which meant builders could throw the houses together without the need for ground floor first fixing which would hold the builder up. Only way to drain them is one rad at a time.

    why are you draining them?

  • Registered Users Posts: 680 ✭✭✭JazzyJ

    It's a closed system.

    All the upper floors have drained fine and one of the bleed valves is completely off. To be honest I don't particularly want to get into any more pipework!

    That's my fear! I just can't find one anywhere.

    Thats what I'm guessing. House is from the late 80s.

    I was replacing a leaking valve upstairs and thought it might an an opportune time to give the system a clean. There was also a bit of work done a few years ago by a plumber (on the upper floor) which required draining the upstairs floors and there was no inhibitor put in after that so it's probably a bit diluted.

  • Registered Users Posts: 12,571 ✭✭✭✭Dtp1979

    dont worry, draining the radiators won’t clean the system, not even a bit. And don’t go adding inhibitor into the system unless it’s been powerflushed first.