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  1. #27
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    Quote Originally Posted by RoBoTeq View Post
    I'm not making this a fact. Just an assumption based on heresay and manufacturer's not addressing it any differently. What you state makes sense as well. Then again, I urge techs to lower indoor airflow to increase latent heat removal which also reduces efficiency.

    Sometimes it's not all about efficiency
    Amen,at least in steamy Florida,comfort rules!

    Customers report raising the stat temps as they are cold,same with lower cfms for heat pumps,wonder where the SEER is at < 400 and even < 350 cfms per ton.

  2. #28
    Join Date
    Nov 2007
    Posts
    47
    Quote Originally Posted by RoBoTeq View Post
    On a 50' line the capacity using 7/8" instead of 1-1/8" is 97% of full capacity.

    So, if a 3 ton unit actually did produce 36,000 Btu of cooling (which they don't), it would only produce 34,920 Btu of cooling using a 7/8" suction line.

    Do not mess with the liquid line though. Big difference between liquid and vapor.
    Is this 3% reduction in capacity independent of the size of the heat pump, or does this percentage increase as the capacity of the heat pump increases?

    For example, if a 3-ton unit has a 3% reduction in capacity, is this also true for a 4-ton and a 5-ton? Or, would a 4-ton have something like a 6% reduction and a 5-ton have a 9-10% reduction?

    TLY

  3. #29
    Join Date
    Nov 2007
    Posts
    47
    Quote Originally Posted by dash View Post
    Check the mfrs. specs,might just be a 3% capacity loss.
    Are these specifications published? I need to know by what percent the capacity of a Goodman GSH130481AA Heat Pump (4-ton) is reduced by using a 7/8'' O.D. suction line rather than the specified 1-1/8'' O.D. suction line for a 50' line.

    Also, I'd like to know if this reduction equally affects sensible and latent capacities.

    Thank you,
    TLY

  4. #30
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    Published by some if not all brands,may be difficult to find,ask your contractor.

  5. #31
    Join Date
    Nov 2007
    Posts
    47
    Quote Originally Posted by dash View Post
    Published by some if not all brands,may be difficult to find,ask your contractor.
    I was hoping to find the information here from someone. If I bought a lottery ticket and asked my contractor for this information, well...let's just say my odds would be better winning the powerball.

    Where did you get your original 3% capacity loss information?

    Thanks,
    TLY

  6. #32
    Join Date
    Jun 2007
    Location
    Metro St. Louis
    Posts
    181
    Quote Originally Posted by TLY View Post
    Are these specifications published? I need to know by what percent the capacity of a Goodman GSH130481AA Heat Pump (4-ton) is reduced by using a 7/8'' O.D. suction line rather than the specified 1-1/8'' O.D. suction line for a 50' line.

    Also, I'd like to know if this reduction equally affects sensible and latent capacities.

    Thank you,
    TLY
    I glanced thru the two versions of the HP specs that I have. The numbers provided in the document did not change when they spec'd the larger size lines.

    I would therefore conclude that the specs provided are based on 7/8", and either the larger size didn't have an appreciable impact or they just haven't finished updating the numbers for the larger size.

    Finally, do a google on "GSH13 specs". The ones I saw all had 7/8" specified. If the numbers are the same, then stop worrying about it.

  7. #33
    Join Date
    Nov 2007
    Posts
    47
    Quote Originally Posted by Waterloo View Post
    I glanced thru the two versions of the HP specs that I have. The numbers provided in the document did not change when they spec'd the larger size lines.

    I would therefore conclude that the specs provided are based on 7/8", and either the larger size didn't have an appreciable impact or they just haven't finished updating the numbers for the larger size.

    Finally, do a google on "GSH13 specs". The ones I saw all had 7/8" specified. If the numbers are the same, then stop worrying about it.
    Thank you, Waterloo, from your search suggestion I did find a service manual and found the information I have been looking for. On page 45, there is a table "Capacity multipliers as a function of suction line size & equivalent lenght" that indicates I will have a 4% capacity loss by using the 7/8'' line @ 50 ft. A 5-ton unit will have a 7% loss of capacity.

    What this means for me is that a 4-ton unit will have 43,200 Btu's/hr cooling capacity. (45,000 x 94%) That's 3.6 tons of cooling.

    TLY

  8. #34
    Join Date
    Dec 2006
    Location
    Dallas
    Posts
    189
    I.D. = 1.00 = 0.785 SQ IN
    I.D = .75 = 0.441 SQ IN

    0.785 / 0.441 = 78% reduction in surface area. (or 0.75" has 56% of the surface area of 1.00", how ever you want to look at it)

    If you can drywall and paint it's probably going to save you $$$ over the years. If you spend $1000 on drywall and a painter, probably not worth it even in 10 years. If you have a leak in the old lineset - probably worth it.

    I had a new 1 1/8" and 3/8" ran through 35ft of wall last year - cost me a case of beer to trick my brother to do the drywall. Tricked wife into painting. Absolutely worth the xx% efficiency savings.

    Anybody find any hard efficiency % yet?

  9. #35
    Join Date
    Dec 2006
    Location
    Dallas
    Posts
    189
    TLY, you are correct - per that manual for a 5Ton until the loss on a 50 ft lineset is 7%.

    Here's how it pans out:

    Tons 5
    Annual Cooling Consumption $1,500
    Efficiency loss 7%
    Cost without 7% loss $1,395.00
    Annual loss $105.00
    Drywall bill $1,000
    Years for break even 9.523809524

    I always find ways to bend the rules about talking about pricing.

  10. #36
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    Quote Originally Posted by TLY View Post
    I was hoping to find the information here from someone. If I bought a lottery ticket and asked my contractor for this information, well...let's just say my odds would be better winning the powerball.





    Where did you get your original 3% capacity loss information?

    Thanks,
    TLY
    Memory from another brand,similar situation,could be 4% maybe more,always check.

  11. #37
    Join Date
    Nov 2007
    Posts
    47
    Quote Originally Posted by gonekuku View Post
    I.D. = 1.00 = 0.785 SQ IN
    I.D = .75 = 0.441 SQ IN

    0.785 / 0.441 = 78% reduction in surface area. (or 0.75" has 56% of the surface area of 1.00", how ever you want to look at it)
    Not to be picky, but the volume of the 1 inch pipe will be reduced by 44% when going to the .75'' pipe. Also it is a reduction in volume, not surface area.

    Thanks for your information.

    TLY

  12. #38
    Join Date
    Jun 2007
    Location
    Central, FL
    Posts
    871

    Hmm Ok

    I agree, according to the Trane manual you may lose about 3% of capacity, I do know for a fact that Goodman has change several Manuf. recommendations in order to meet the ARI standards in capacity & EFF. Just remember to do a subcooling check on the unit to asure a proper charge. However, if you do start to lose compressors and a goodman rep goes out there it will void your warranty. The odds of that is slim but it has happen and can thats were your judgement comes in. Good Luck!
    WARNING:IF YOU DON'T KNOW THEN DON'T DO, SO THOSE WHO KNOW WHAT YOU DIDN'T KNOW DON'T END UP UNDOING WHAT YOU DID SO IT COULD GET DONE RIGHT!

  13. #39
    Join Date
    Nov 2000
    Location
    Eastern PA
    Posts
    68,923
    All ratings are under ideal lab conditions. Trying to nitpick about capacities and efficiencies can drive you crazy for absolutely no gain. Every time you turn your system on it changes efficiency and capacity statistics (unless you know for a fact that the voltage in your home is constant and you change your filters between every start up).
    Government is a disease...
    ...masquerading as its own cure…
    Ecclesiastes 10:2 NIV


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