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  • FIRST POST
    • Mr Proctalgia
    • By Mr Proctalgia 13th Oct 06, 2:26 PM
    • 961Posts
    • 818Thanks
    Mr Proctalgia
    Injection Tee (Plumbing question)
    • #1
    • 13th Oct 06, 2:26 PM
    Injection Tee (Plumbing question) 13th Oct 06 at 2:26 PM
    Does anyone know where I can get an Injection Tee from? My system has Gravity Hot water and pumped CH (and I cannot stop it making hot water as its from a range cooker) It goes all wonky when the CH is on and stops the gravity flow. Could I make one from a 28mm = Tee and a 22mm pipe reducer or are they more specialised??

    TIA
    The quicker you fall behind, the longer you have to catch up...
Page 1
  • BobProperty
    • #2
    • 13th Oct 06, 6:53 PM
    • #2
    • 13th Oct 06, 6:53 PM
    Sounds like you need a re-arrangement of the plumbing pipework. What is an "Injection Tee" by the way? If you are trying to add just a method of having only the CH on and no hot water, then be aware that the range may require the hot water loop to be there all the time. This isn't my specialist subject but I do think a reworking of the pipework may be needed to achieve what you are looking for.
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    • plumb1
    • By plumb1 13th Oct 06, 7:05 PM
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    plumb1
    • #3
    • 13th Oct 06, 7:05 PM
    • #3
    • 13th Oct 06, 7:05 PM
    The injector tee is a special fitting, it is usualy made of stainless steel and will have pre-drilled holes which divert the water into the heatexchanger.
    You will need the make/model to order 1.
    There could be 1 already fiited as they are sometimes fitted straight into the boiler, but it could also be piped up wrong.
    As it is best to cross pipe.


    You can let Live help here

    http://www.rangecookers.co.uk/home.html
  • BobProperty
    • #4
    • 13th Oct 06, 7:42 PM
    • #4
    • 13th Oct 06, 7:42 PM
    Plumb1, I think we need more info from MrP as I was taking the phase "range cooker" to mean any sort of range cooker e.g. Rayburn. We don't know if it is solid fuel for instance. He could live in the wilds of the Peak District :confused:
    I was thinking he could have an old Rayburn type set up with hot water and a handful of rads that someone had "improved" at some point in the past by adding the pump.
    A house isn't a home without a cat.
    Those are my principles. If you don't like them, I have others.
    I have writer's block - I can't begin to tell you about it.
    You told me again you preferred handsome men but for me you would make an exception.
    It's a recession when your neighbour loses his job; it's a depression when you lose yours.
    • Mr Proctalgia
    • By Mr Proctalgia 13th Oct 06, 8:37 PM
    • 961 Posts
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    Mr Proctalgia
    • #5
    • 13th Oct 06, 8:37 PM
    • #5
    • 13th Oct 06, 8:37 PM
    Ok Folks - Yes its a gas fired Rayburn, not too old either. The set up is that it has one heat exchanger (Single flow and return) and two burners. One burner purely for CH, this is controllable electically via a stat, timer etc it also features pump overrun. The second burner is for "cooking" and is designed to leak up to 2.5Kw to the heat exchanger. This side of it has to work as a gravity feed to the (indirect) cylinder with if necessary a further heat soak across it as well. The central heating side can be either S plan or Y plan, but if S plan has to have a bypass fitted.

    The thought behind an "Injector tee" is that as the return from the cylinder and the return from the CH tee together on the return to H/E the pumped return stops the gravity flow, this is cured (for want of a better word) by reducing the diameter of the pumped return inside the tee and thus creating a venturi that sucks the gravity flow along with it. Imagine a 28m tube reduced to say 22mm with a pipe reducer and then stuck into the Tee so on looking into the Tee of the Tee Fitting you can see the end of the 22mm reducer, this acts as a jet that sucks the gravity return in around it (Still with me so far) and thus assists the flow to the DHW.

    HTH LOL
    The quicker you fall behind, the longer you have to catch up...
  • Mike4
    • #6
    • 13th Oct 06, 9:00 PM
    • #6
    • 13th Oct 06, 9:00 PM
    I don't know any company still making injector tees, but I'd imagine one could be made quite easily....

    I'd use a 28mm endfeed tee and a 28mm x 15mm fitting reducer. Cut the 28mm end of the fitting reducer down to about 5mm in length then insert it into the 28mm tee, with the 15mm end pointing into the tee as the injector nozzle. Install it and see if it works!

    Hope that helps.

    Cheers! M4
    • Mr Proctalgia
    • By Mr Proctalgia 13th Oct 06, 9:09 PM
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    Mr Proctalgia
    • #7
    • 13th Oct 06, 9:09 PM
    • #7
    • 13th Oct 06, 9:09 PM
    Just had another thought! I wonder if a 22 - 28 - 28 swept tee with the pumped side into the 22mm end would do the job?
    The quicker you fall behind, the longer you have to catch up...
    • plumb1
    • By plumb1 13th Oct 06, 9:30 PM
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    plumb1
    • #8
    • 13th Oct 06, 9:30 PM
    • #8
    • 13th Oct 06, 9:30 PM
  • Mike4
    • #9
    • 14th Oct 06, 10:57 AM
    • #9
    • 14th Oct 06, 10:57 AM
    Nice drawing. What did you use for it?

    However, I think this design would be dangerous and contravene the range cooker installation instructions. The original poster's system is probably designed with uncontrolled gravity primaries to the hot water cylinder so there is a heat sink to prevent the range cooker boiling it's water.

    Cheers! Mike4
    • plumb1
    • By plumb1 14th Oct 06, 4:35 PM
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    plumb1

    However, I think this design would be dangerous and contravene the range cooker installation instructions.
    by Mike4
    This is Range detailed layout, as per their installation instructions, how can it be dangerous, it clearly shows a open vent.
  • Mike4
    This is Range detailed layout, as per their installation instructions, how can it be dangerous, it clearly shows a open vent.
    by plumb1

    To quote the original poster, "I cannot stop it making hot water as its from a range cooker".

    It is impossible to prevent a solid fuel appliance producing heat when it is alight, hence the need for a heat sink (or heat leak), and the pipework layout you posted does not provide one. An open vent by itself is not good enough.

    Without any sort of heat leak installed, the range will quickly boil its water when neither CH nor HW is calling for heat. Steam discharging continuously from the open vent is most definitely not a Good Idea, and if the cold fill and open vent pipes should ever freeze, the range will turn into a bomb.

    Hope that helps... ;-)

    Cheers!
    M4
    • plumb1
    • By plumb1 14th Oct 06, 6:29 PM
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    plumb1
    Heatranger Models 216SFW & 355SFW

    With these models it is normal installation practice to pump-assist the central heating circuit, whilst retaining gravity circulation for the domestic hot water pipe-work.
    The heating pipe-work should be a two-pipe, small bore system with the radiators having the appropriate control valves and lock-shield valves for balancing. The control valves may be thermostatic, but it is recommended that at least one radiator should remain in operation with a manual valve, to serve as a heat-leak
    An injector tee (supplied with the Rayburn) must be fitted as shown below, to ensure that the gravity hot water circulation continues even when the pump is in operation. Note the correct position for this fitting. Drain-cocks should be fitted at the lowest points of the system.
    • plumb1
    • By plumb1 14th Oct 06, 6:34 PM
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    plumb1
    • plumb1
    • By plumb1 14th Oct 06, 6:36 PM
    • 2,979 Posts
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    plumb1
    • plumb1
    • By plumb1 14th Oct 06, 6:48 PM
    • 2,979 Posts
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    plumb1
    if the cold fill and open vent pipes should ever freeze, the range will turn into a bomb.


    M4
    by Mike4
    It is not a solid fuel appliance(gas)
    if the F/E were to frezze in any(gas,oil, solid fuel) open vented system it would explode, in extream case. More likely to evaporate water(steam) and boil dry, ending in cracked heat exchanger.
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