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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?
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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.
The great professors of the art are not immune from the malignancy of matter and the eternal cussedness of inanimate objects.
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I used a night light for that type of stuff.
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I use a piece of plywood to restrict airflow coming from condenser to raise head pressure to desired COA temperature.
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For example 95*ODA +DTD of 20* =115* condensing temperature.
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Check out Fan Handler- LA240.
Its basically a head press. control and it has worked great for me.
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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.
Nest is POO!!
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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.
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Originally Posted by
CHAINIK
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!!!
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Originally Posted by
HVAC_Marc
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.
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Tarp around the condensing coil. Only wrap as much as needed to get the condensing temperature you want.
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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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Field piece makes an adjustable charging jacket. It straps onto the top of the unit with an adjustable drawstring hole on top to adjust the amount of airflow let through to get the exact pressures you want.
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Originally Posted by
shellkamp
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.
Curious,
I always thought that if my liquid line was 95 and a clean condenser puts out a liquid line temp that is within 2 or 3 degrees of ambient, then it is exactly the same thing as running the condenser in a 92 to 95 degree ambient. Am I missing something?
I understand that most condensers are designed with a dedicated sub cooling circuit that - of course - will not really get used as such when the condenser is wrapped with a tarp. But if one moves 2 tons of BTUs with a big coil and 95 degree air as one does with a little coil (made so by a trash bag) and 30 degree air, then the refrigerant doesn't know the difference. My subcoolong readings bear that out very consistently. And this is the design philosophy behind flooded condenser systems. Can you clarify your viewpoint maybe? Just because I am sure does not mean I am right.
You cannot really tell if the coil is dirty with this method of course, but for charging it is right on the money in my experience.
I liked to use super light weight plastic. Folds up small, and the air movement keeps it sucked up against the coil and in place. And it takes no time to set up whatsoever. Sometimes I borrow a trashcan lid and put my toolbag on it if I am too lazy to go to my truck to get it.
Dont forget to run the furnace for a few minutes to give yourself a little load in the space if it is cool inside.
Hmmmm....smells like numbatwo to me.