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Discuss Bleeding antique heating system in the Central Heating Forum area at

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  1. Jamie_

    Jamie_ New Member


    We have recently moved in to our first house, and are now expecting our first baby.

    Working through the list of things to do, one was to replace the heating system, the new arrival has put a slight delay to that.

    I am just redecorating the box room to become a nursery and need to remove the radiator - no issue doing this my self, the question is how I go about refilling the system?

    The setup is OLD, there is a Concord Companion H 45/55 back boiler, a hot water tank which works on gravity / convection and a central heating pump under the floor boards. There is a drain tap (possibly fill point?) Under the floor boards near the pump. There is no pressure vessel for the heating system, no expansion tank in the loft and no filling loop. There is an immersion heater in the tank, but that has no thermostat so it's very rarely used, in fact there is no bypass valve either on the hot water tank, this gives two issues, if there is no hot water and I switch it on, if the central heating is running it seems to take priority as it's pumped, also if it's a cold day and the heating is on a lot you end up with extra hot water!
    I have put a Tado control system which I brought with me that actually controls the setup quite well.

    Sorry for the long post but to recap the question is really how I bleed the system after removing the rad?
    The boiler does klunk and bang a lot, is this likely air in the system?
    Is it worth getting a plumber to refill the entire system with an additive? Will many plumbers know how to fill a system like this?

    Thanks in advance.

  2. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    You should have a little metal tank either in the loft of above the cylinder smaller than 2 foot square

    Once your finished put the rad back on and open the valves you should hear a bit of water enter the rad, wait for this to stop and check your joints

    Open the air bleed screw on the rad you should hear said metal tank start to fill, close the bleed screw once you have water

    And they tend to do on gravity hot water
    • Like Like x 2
  3. Jamie_

    Jamie_ New Member

    Hi Shaun,

    Thanks for the speedy reply!

    The klunks and bangs we can put with for now, just after doing a bit of research I thought it might be linked to air in the system!

    I've just been and rechecked, there is definitely no tank, it 'looks' like the pipe from the boiler to the cylinder continues to the loft and goes in the lid of the hot water heater tank it is above the overflow pipe for the tank so I am assuming this means it isn't a sealed system and this is how the system allows the water to expand.

    The header tank has a small bore cold water feed with an anti chatter suppressor going to the float valve on top, a large bore pipe from the bottom that goes down to the cylinder, a plastic overflow drain a few cm from the top, then this large bore pipe in the lid of the tank which is open inside ie no valve or cap and is well above the water level.

    The only think above the cylinder is towels!


  4. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Should have two tanks in your loft

    If you only have one don't put any chemicals in your heating system as it uses the same water as your hot cylinder
    • Like Like x 1
  5. Jamie_

    Jamie_ New Member

    I'm guessing rightly or wrongly, the hot water and heating are two different circuits, I know from previously draining my parents heating system (a lot newer than this system) the heating circuit water was pretty manky.
    I'm thinking if my system can expand into the cold header tank I don't fancy that 'gunk' making its way through some of the mixer taps we get 'clean' cold water from?
  6. Best

    Best Trusted Plumber Top Contributor!!

    Maybe a primatic cylinder.
    It will feed the radiator when you turn rad valves back on and bleed air
    • Agree Agree x 2
    • Like Like x 1
  7. Jamie_

    Jamie_ New Member

    Hi Best,

    Thanks for your reply, just found the image of the system, looks like this could be the system! I will continue and hope for the water to flow once the room is done! [​IMG]

    Thanks again Shaun I will not add any additives!

    I'll go carry on filling the 82 screw holes in the box room walls - the joys of buying a house from a DIY machinist o_Oo_O

    Thanks again!

    • Like Like x 1
  8. Best

    Best Trusted Plumber Top Contributor!!

    And if I were you, I would replace the entire system when you can afford to.
    A quality new sealed heating system with modern controls would be better.
    You would be advised to have at least minimum a TRV on the baby's bedroom rad to keep the heat under control at a max of 17 degrees. Too much heat is a no no for babies I believe and best the entire home has a stable temperature.
  9. JCplumb

    JCplumb Plumber

    Could be a fortic cylinder so it has it's own 'header' tank and the tank in the loft is just for heating feed/expansion.
  10. Jamie_

    Jamie_ New Member

    Best, a new system is on the cards, it was going to be this year but then the new arrival changed plans slightly!
    I plan on relocating the boiler to the garage - it's a detached garage but the gas, cold water feed a hot water tap and a main drain are on the corner of the house around 8 feet from the garage, there is also an office built onto the back of the garage so it would mean I could add heating to it. Not sure if reg's would allow that, boiler in the garage?

    I have ordered a Tado TRV set and plan on one going into the baby's room to control it's temperature a bit more precisely. Now I know the system can be bled a bit easier.

    JC looking at that cylinder you mention looks different to the one we have ours is quite a small cylinder maybe only 3 feet tall
  11. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Yes you can have a boiler in a garage aslong as you follow the regs and insulation is installed to the pipework
    • Like Like x 1
  12. Chuck

    Chuck Active Member

    You'll probably need an independent gas heater for the the garage office. You'll get all sorts of control problems trying to share a boiler between two such different buildings.
    • Like Like x 1
  13. Jamie_

    Jamie_ New Member

    Thanks Shaun, I was thinking of laying a trench around a metre deep and then insulating the pipework. I'll look up the reg's nearer the time to make sure it complies!

    Thanks Chuck, I'd probably say at the moment the office is better insulated than the house :rolleyes: I've just been looking as I'm just in the stages of finishing the office so no flooring is down yet, would you recommend an electric under floor heating kit, area is only around 7m2 and thinking of putting down wood flooring?

    One last question, is there any guide or procedure to follow to refill the primatic system?

    Thanks again everyone!
  14. sammathias

    sammathias Plumber GSR

    Just fill it up. You may find your hot water to be dirty. But let it settle for a coupld of hours before drawing any hot off. Also dont use inhibitor.
  15. Chuck

    Chuck Active Member

    If you are considering underfloor heating, consult the forum sponsor:

    Electric Underfloor Heating | Warm Water | Under Floor Insulation | Frost Protection | Uheat

    Without knowing a lot of detail it's difficult to be specific but I would consider installing a couple of radiators fed from the main heating (for the times when the main CH is needed to heat the house) and also an independent gas heater to use when the weather is too mild to need the heating on in the house.

    I doubt that UFH would be a good way to heat a small garage office that is presumably only occupied for 40 hours a week but you should consult a specialist. It does have the advantage that it doesn't need wall-space.
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