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A quick question for the HVAC folks.

Discussion in 'Off-Topic' started by Wrench75, May 16, 2019.

  1. Wrench75

    Wrench75

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    Take a look and let me know what you think. Thanks.

     

  2. zboys

    zboys NES Member

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    Yes it should be blowing straight up, did you exchange with exact motor/blade. Any chance blade was flipped
     
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  3. grizquad

    grizquad NES Member

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    I used to use a shop rag for my"suck test". Did you change fan from original motor to new motor? I would check with manufacturer web site and see if they have a different pitch fan that will solve your problem. You should be getting strong airflow out the top (hot air) and strong suction across the coil ( the whole coil). Good luck
     
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  4. Asaltweapon

    Asaltweapon NES Member

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    Is the replacement fan motor the same size (height) as the old one?
     
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  5. arsco

    arsco NES Member

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    The bottom edge of the shroud should be at about the middle of the fan blades. Sometimes non OEM motors will have a longer depth forcing the fan to far into the condensing unit
     
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  6. mgrick02

    mgrick02

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    Basically it’s hard to say now. It’s not rocket science but as you know now should have measured the blade height before proceeding. New motor could be longer in height and the shaft longer . It just needs to be close to the shroud and go from there.
    And how’s the cooling? You don’t have a set of gauges to check the head pressure to see if running efficiently.
     
  7. Wrench75

    Wrench75

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    The motor is an exact replacement. It's made by a different manufacturer but the specs and dimensions are identical. I reused the fan and it is definitely not flipped over.
     
  8. Wrench75

    Wrench75

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    Cooling is a bit better. I did measure the height of the fan and set it to the same place. As I said in the vid it is venting exactly the same way it was before the motor shit the bed. However they stopped making this model in 2004 and the capacitor in it was dated may 2010. So someone has been in it and replaced at least the cap but could have replaced the motor as well so there is no guarantee that it was set right when I bought this pace last year. My engineering schooling made me OCD about details lol. So I made sure it is set up EXACTLY the way it was. For whatever that is worth in this case.

    For that matter, before I set the fan height I flipped the motor over and lowered the fan as close to the motor as I could while still being able to spin it. Then I measured the gap from the edge of each blade to the same spot on the motor's casting with a feeler gauge just to make sure I didn't tweak it when I took it off the old rusty shaft it was fused to. Like I said OCD.

    I'll try raising the fan a bit and see if it helps. Thanks.
     
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  9. mgrick02

    mgrick02

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    I was going to say make sure the mf are the same for the run capacitor. Should be if it’s the same specs as the old motor. They say you should always replace the run cap with a new motor. Most are dual run caps in a condenser. One side for the compressor and the other side for the fan.
     
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  10. Wrench75

    Wrench75

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    I did replace the cap and it also is an exact match. 35/5 mf 440v dual run round. It starts and runs just fine it's the heat exhaust that is the only problem. Thanks.
     
  11. wilco_99

    wilco_99

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    It's not a problem with the fan blade....you have a dirty condenser coil. Get some coil cleaner and give it a good cleaning. index.jpg
     
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  12. arsco

    arsco NES Member

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    I would assume the motor has been changed before.

    I also wouldn't worry to much. Make sure the compressor isn't over amping and move on.
     
  13. arsco

    arsco NES Member

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    Nubrite is some nasty stuff. Be careful. nasty on skin and will eat most finishes
     
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  14. wilco_99

    wilco_99

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    Stuff works great! Just mix it to directions.
     
  15. arsco

    arsco NES Member

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    Does work great. It's just nasty stuff.

    Pumped about 40 gallons through my coil gun in the last few weeks
     
    Last edited: May 16, 2019
  16. Asaltweapon

    Asaltweapon NES Member

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    I wait till after the pollen season.
     
  17. arsco

    arsco NES Member

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    Ya me too. RTUs next to construction running high head.

    Dust from the on site cement plant and all the dirt next door has not been fun
     
  18. Wrench75

    Wrench75

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    That's a nice thought but it doesn't change the fact that the system couldn't get the house below 80 deg. during the summer last year. It would literally run all day and never stop. I would have to manually shut it down and turn it back on 15 min later. I'm pretty sure there is a separation in the duct work. The volume coming out of the vents on one side is very low compared to the other side.

    The unit is a 3 ton cooling a 1260 sq/ft double wide. I had the warranty co. send down an HVAC tech a few months ago and he checked the pressure, A-coil (which is practically brand new), etc... He agreed that it should be cooling the place better and said he also thinks there is a duct problem. Then told me that the warranty co. doesn't cover duct work.

    I just want to make sure that the condenser is working as well as possible before I go under and start pulling down the vapor barrier and insulation to deal with the ducts. I'm probably going to buy an all in one outside unit and call it a day. But since I'm a stay at home dad with a baby about to turn 1 next month time is at a premium to say the least. I'd like to get it running well enough to get us through the hotter months and deal with it in the fall when I'll have more time available since I'll be doing the install. Then having someone come down and charge me an arm and an a**h*** to charge the system.
     
  19. Wrench75

    Wrench75

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    So I should pull off the black grate before spraying to save the paint?
     
  20. arsco

    arsco NES Member

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    Ill do the best i can to help over the interwebs. i missed or didn't know about an underperforming system complaint.

    If you don't have all the tools needed to give us the info not much I can do from this side
     
  21. Wrench75

    Wrench75

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    Also, from what I have read you should expect to cool about 400 sq/ft per ton under ideal conditions. So this unit is just a hair under sized and SC heat is far from ideal conditions. It's 82 right now and going to be 89 tomorrow. It was 78 in here when I turned the unit on 2.5 hrs ago. It's still 78 in here. I'm thinking I should step up to a 4 or 5 ton?
     
  22. Wrench75

    Wrench75

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    Actually my BIL 10 min away is an HVAC tech and has all the tools. He also recently tried to have my FIL bring my son to him so he can baptize him against my wishes (BIL is a deacon). So I told him the next time I see him I'm going to beat him into a coma. Which I have every intention of doing. So I won't be borrowing his tools or having him come look at it.
     
  23. zboys

    zboys NES Member

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    I doubt your undersized at 3 tons, a doublewide trailer?
    Id check the returns first, and any chance you have a zone damper in one half that isnt opening?

    With AC I never guess, do a heat gain and see exactly what you need, too big will give you more problems.
     
  24. wilco_99

    wilco_99

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    Maybe this will help? It's where I would start anyways.
    If the condenser is not blowing air out the top, your not moving air. If your not moving air through the condenser your not condensing. If your not condensing your starving the evaporator. If you starve the evaporator you get poor cooling. Start with cleaning the condenser.

    A 3ton unit should cool that trailer no problem unless it has walls of Swiss Cheese.
     
    Last edited: May 19, 2019 at 6:44 AM

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