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  1. #1
    Join Date
    Nov 2013
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    Looking for a tool to simulate 95 degree OAT on condensing unit

    Hi, I'm looking to put additional effort into testing delivered BTU's in the summer time. However, I often test the equipment in the morning before I reach the ideal 90 degree plus high OAT. I know there are some tools- restrictors & jackets- that can be used for simulating that high OAT. Can anyone recommend some tools that they have experience with?

  2. #2
    Join Date
    Apr 2010
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    Austin
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    Fieldpiece and probably others make windsocks and stuff like that. I predict a series of posts after this advising you to use cardboard, which will also work.


  3. #3
    Join Date
    Feb 2016
    Location
    Louisburg Kansas
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    I used a night light for that type of stuff.

  4. #4
    Join Date
    Sep 2015
    Location
    Indianapolis ,Ind.
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    I use a piece of plywood to restrict airflow coming from condenser to raise head pressure to desired COA temperature.

  5. #5
    Join Date
    Sep 2015
    Location
    Indianapolis ,Ind.
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    For example 95*ODA +DTD of 20* =115* condensing temperature.

  6. #6
    Join Date
    Mar 2010
    Location
    Rochester, NY
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    Check out Fan Handler- LA240.
    It’s basically a head press. control and it has worked great for me.

  7. #7
    Join Date
    Mar 2013
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    Billington Heights, NY
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    I dont know if there is any one "tool" that will do what you want, but in the past I have worked in situations where a small tent has provided a new fake " ambient atmosphere". You still have all the air flow but the tent allows the temperature inside to rise. In very low ambients you can use a torpedo heater to help raise ambient temperature.
    Experience - knowing when to get the hell out of the way and plug your ears. "Don't be a sissy. Turn it on!"

    Glennac - Failed my biology test today: They asked, "What is commonly found in cells?" Apparently "BL*** people" wasn't the correct answer.
    Poodle Head Mikey - "the world is well populated with the unknowing and the uncaring and the stupid."

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  9. #8
    Join Date
    Nov 2001
    Location
    east kansas
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    I've used a painters tarp and some strong magnets from Home Depot. Throw the tarp over the unit and let the tarp balloon up and recirculate the discharge air. Then I can regulate a corner opening for the head pressure I want.
    Beware of advice given by some guy on the Internet.

  10. #9
    Join Date
    Mar 2015
    Location
    Medford, N.Y.
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    Quote Originally Posted by CHAINIK View Post
    Fieldpiece and probably others make windsocks and stuff like that. I predict a series of posts after this advising you to use cardboard, which will also work.
    LOL. Using cardboard to control head pressure? Really?? Can it be?

    OH YEA! OH YES! It is written as so, in RSES, by RSES, for US TO USE AS A TOOL!!!

  11. #10
    Join Date
    Apr 2017
    Location
    Athens, Wi
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    Quote Originally Posted by HVAC_Marc View Post
    I dont know if there is any one "tool" that will do what you want, but in the past I have worked in situations where a small tent has provided a new fake " ambient atmosphere". You still have all the air flow but the tent allows the temperature inside to rise. In very low ambients you can use a torpedo heater to help raise ambient temperature.
    This is the best way. Go buy a ground blind from your favorite outdoor store and us the zipper on the door to adjust your temperature.

  12. #11
    Join Date
    Apr 2018
    Location
    HoustonTexas
    Posts
    22
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    Tarp around the condensing coil. Only wrap as much as needed to get the condensing temperature you want.

  13. #12
    Join Date
    Mar 2013
    Location
    Port St. Lucie, Fl
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    Just be aware that when you simulate the 95 degree ambient, that it won't be the same as the real deal due to altering of the heat transfer characteristics of the coil. You could have a 115 degree Saturated condensing temperature but due to the lower airflow the subcooling (and therefore BTU output) will not be the same as it would be when it is actually 95 degrees out. A TXV system would fare better than a fixed orifice system using this method.

    It really should only be used to get you in the ballpark as far as charging the system in cold weather.

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