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  1. #1
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    Question about split systems



    Dear Friends,

    At split unit system while orifice as expansion valve is on outdoor unit, When you want install it, for example you see there are 5m copper pipes for installing.

    I had discussion with one of my friends :

    1 – He told me this 5m is accidentally and we can increase this length as long as we want.

    2 – I told him 5m copper pipe has plan behind. The initial diameter of orifice was calculated. When liquid line exits form condenser and pass form that orifice, Frigidity will starts 5m further by this reason company has put 5m copper pipe for jointing condenser to evaporator.

    If it is possible please share your knowledge with me.

    Sincerely yours.



  2. #2
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    Re: Question about split systems

    It depends on the manufacturer.

    Most installation instructions will state that the system refrigerant charge is sufficient for a certain length of pipe. If the length is extended, up to a specified maximum length, then a specific additional amount of refrigerant per metre should be added during commissioning.

    In modern, good quality, splits the expansion valve is electronic and the unit software maintains the required pipe temperatures.

    [Edit - 1] Daikin installation manual, https://bit.ly/2sHThQB , gives details of adding additional charge.

    [Edit - 2] Daikin service manual, https://bit.ly/2kVFth4 , check piping diagram for expansion devices.
    Last edited by Brian_UK; 08-06-2018 at 08:57 PM.
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  3. #3
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    Re: Question about split systems

    Quote Originally Posted by Brian_UK View Post
    It depends on the manufacturer.

    Most installation instructions will state that the system refrigerant charge is sufficient for a certain length of pipe. If the length is extended, up to a specified maximum length, then a specific additional amount of refrigerant per metre should be added during commissioning.

    In modern, good quality, splits the expansion valve is electronic and the unit software maintains the required pipe temperatures.

    [Edit - 1] Daikin installation manual, https://bit.ly/2sHThQB , gives details of adding additional charge.

    [Edit - 2] Daikin service manual, https://bit.ly/2kVFth4 , check piping diagram for expansion devices.
    Dear Brian_UK,
    First of all thanks for your reply.

    I know and you are right, When we increase pipe length we must charge more refrigerant as said in instruction.

    But still I have an important question, Suppose that we have 25m length between outdoor unit (condenser) and indoor (evaporator).
    Most of times as result of competition on price companies use orifice or capillary tube instead expansion/electronic expansion valve and this orifice is in outdoor (condenser).

    My question is here, Liquid line pass from orifice at outdoor unit and goes 25m (for example) until reach to evaporator.

    This 25m pipes length is same as evaporator ???! because as you know when liquid passes between orifice frigidity will start. Isn't it ?

    Sincerely yours.

  4. #4
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    Re: Question about split systems

    The liquid line is insulated so it is not the same as evaporator.
    When there is a suction line accumulator or liquid receiver in the outdoor unit the minimum pipe length exist,
    usually it is 5m. If the pipe length is less than 5m the unit will be overcharged.

  5. #5
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    Re: Question about split systems

    .

    Yes, think of the liquid line as an extension of the evaporator and that is the reason why it should be insulated. The instant the refrigerant enters this liquid line the refrigerant is saturated. This line is called a saturated line and for that reason it must be insulated.

    Rob

    .
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