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New heat pump with 5/16" liquid line?

Does anyone know of manufacturer that has ratings for their heat pump to be used with a 5/16" liquid line? We have a replacement job, that has an existing 25' silv flos'ed liquid line that we would like to re use. I know most manufacturers now are calling for 3/8", But if possible we would like to re use this line and save the customer the extra charge in having it replaced. Thanks to all. '

Comments

  • Steve Minnich
    Steve Minnich Member Posts: 2,642
    About 25 years ago, I had a compressor fail within the warranty time frame. I was denied the warranty because I used a 7/8" suction line on 4 ton system that should have had a an 1 1/8" suction line because of its extended length. That was a hard lesson to learn. I never give them an opportunity to deny, anymore.
    Author - Hard Knocks: My Life Inside Boiler Rooms
    PHC News Columnist
    Minnich Hydronic Consulting & Design, LLC
    https://heatinghelp.com/find-a-contractor/detail/minnich-hydronic-consulting-and-design
    SuperTech
  • JUGHNE
    JUGHNE Member Posts: 8,195
    Was this 5/16 on an old R-22 system?
    Ruud/Rheem did the 5/16 years ago.

    A new 410A HP?
  • zepfan
    zepfan Member Posts: 309
    Thanks for the response. It is a Trane 1987 2 ton, r22 air handler, and we would be installing an 410a hp and air handler
  • unclejohn
    unclejohn Member Posts: 1,700
    Should be ok up to 3 tons. Add as much 3/8th as you can at the unit. I have never had a warranty job denied.
  • JUGHNE
    JUGHNE Member Posts: 8,195
    Is the remaining oil from the R-22 system a concern?
    Or how do you deal with it?
    Or is it as much of the issue that was thought when 410A became popular?
  • John Mills_5
    John Mills_5 Member Posts: 935
    Rheem is fine with it in long lengths up to 3 on, above better be pretty short.

    Otherwise I'd check with tech support on the brand you want to use. I called 1 brand once and was told absolutely nothing less than 3/8". Dead comps usually don't go back so yes, warranty won't be denied but it will cost someone!

    Old lines blow out with nitro and unless you had a burnout, should be OK. Of course if easy to change I'd much rather see shiny new copper. POE oil is a GOOD cleaner removing any crud built up on the inside of the old lines.
  • JUGHNE
    JUGHNE Member Posts: 8,195
    On a walk in cooler I had both TXV plugged screens twice after 134A and new oil.
    So for a heat pump with possibly TXV inside and out, also reversing valve, where is the best place for the bi-flow filter drier.....would one for each end be a consideration?
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 8,602
    5/16 will be fine for 2 tons. Blast it with nitrogen first
  • G Averill_2
    G Averill_2 Member Posts: 45
    Our refrigeration and air conditioning staffs recommend a product by Nu Calgon, item number Rx-11-flush when changing refrigerants. Take a look on their website.
    SuperTech
  • pecmsg
    pecmsg Member Posts: 1,925
    Flushes cause more damage and are not advised. just blow out the line set. No issues with a mixture of POE & MO.
    Remember the POE oil is a cleaning agent, We recommend a suction filter in use for several days to trap any and all crap that will come back to the compressor. Remove it after a few days.
    unclejohnChrisJicy78
  • Cayman
    Cayman Member Posts: 1
    edited March 2020
    Hey guys, I have a similar situation as the original poster here. Replacing a 2.5 ton R22 Trane HeatPump that has an existing 5/16" liquid line. Replacing the unit with a Goodman GSZ140301 (2.5 ton HeatPump) and a Goodman ARUF37C14 a/h. The existing lineset runs through interior finished space of the house and the HO doesn't want a new lineset running up the exterior wall. In this case, the a/h is in the attic with a total 50' lineset run with approx 18' of that being a vertical lift. Goodman's technical publication 107 makes a 5/16" for a/c only applications, but, makes no mention of heatpump applications. Thought I'd reach out to you for your thoughts. Do you think I can get away with using the existing lineset? Thanks in advance.
  • pecmsg
    pecmsg Member Posts: 1,925
    Cayman said:

    Hey guys, I have a similar situation as the original poster here. Replacing a 2.5 ton R22 Trane HeatPump that has an existing 5/16" liquid line. Replacing the unit with a Goodman GSZ140301 (2.5 ton HeatPump) and a Goodman ARUF37C14 a/h. The existing lineset runs through interior finished space of the house and the HO doesn't want a new lineset running up the exterior wall. In this case, the a/h is in the attic with a total 50' lineset run with approx 18' of that being a vertical lift. Goodman's technical publication 107 makes a 5/16" for a/c only applications, but, makes no mention of heatpump applications. Thought I'd reach out to you for your thoughts. Do you think I can get away with using the existing lineset? Thanks in advance.

    and there's your answer.

    Contact Goodman tech support before taking on the job.
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 8,602
    3/8 is good for 3 1/2 tons at 25' so I don't see 5/16 being an issue on 2 1/2 at 25'

    Heat pump or ac makes no difference it's the same amount of liquid flowing only the direction changes. The weight of R-22 and R-410 in a liquid phase is virtually the same
  • ratio
    ratio Member Posts: 2,732
    In the lineset sizing paperworks I've read, the liquid line size was dictated by refrigerant velocity as well as pressure drop & often gave a range of sizes. That said, I can't recall seeing any R-410A A/C system that permitted anything smaller than 3/8". It's possible that it'd work, but I'm quite sure that Goodman, or any other mfgr, will not honor a warranty that doesn't meet their minimum spec.

    If it were me, I'd walk away. I don't know how reasonable the homeowner is, but I know how those kind of things fall out for me.

    Ironman
  • GW
    GW Member Posts: 4,034
    we did that on a condo 3 years ago, no issues yet. 2 ton
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • Ironman
    Ironman Member Posts: 6,339
    edited March 2020
    Get the manufacturer to okay it in writing. If they won't, then tell the customer it has to be changed.

    Gentlemen, we cannot let the customer dictate what's proper design or procedure. That's our job.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    pecmsgicy78ratio
  • ratio
    ratio Member Posts: 2,732
    I just came across a doc about this today, attached. It shows a 5/16" liquid line as being acceptable for up to 31/2 ton with 120' of lift to the condenser.

    And a maximum equivalent length of 90' for a 1/2" suction line on a 11/2 ton unit!!

  • pecmsg
    pecmsg Member Posts: 1,925
    ratio said:

    I just came across a doc about this today, attached. It shows a 5/16" liquid line as being acceptable for up to 31/2 ton with 120' of lift to the condenser.

    And a maximum equivalent length of 90' for a 1/2" suction line on a 11/2 ton unit!!

    That's for Trane the OP is installing Goodman!
  • ratio
    ratio Member Posts: 2,732
    Sure, but it's the same physics. Should work fine (although that's no guarantee the factory will honor their warranty [if necessary]).

    TBH, I posted it for the next person looking for info on using a 5/16 liquid line.

    And to marvel about a 1/2 suction line. I don't do much refrigeration, that sounds way small to me!

  • pecmsg
    pecmsg Member Posts: 1,925
    That chart shows the extra charge if a 5/16th is the liquid line. It also states the new equipment will not have a AHRI # or meet the DOE energy requirements.

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