RE: Superheat for a Marvair 48K wall pack system with a piston?

So what should my target superheat be with a R22 or MO99 system? Marvair compac 1 48K with a piston? I talked to marvair they are telling me 10-12 for superheat and 12-18 for subcooling. I was under the impression w piston was good for 20 degree superheat.

rick1981 Rookie Asked on June 15, 2018 in Commercial HVAC.
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I had to download the I&O manual to see what this was.


Usually with a fixed orifice, I use a superheat calculator that can be downloaded and enter my Indoor Wet Bulb and Outdoor Dry Bulb temperatures and determine my superheat from there.


In my mind, a fixed orifice is a fixed orifice and must comply with the rules, regardless of what type of system it’s installed in. So I have no clue how the manufacturer can determine a generic superheat value.


But on the other hand, I’m not super familiar with the equipment but it looks like a window shaker had a really large baby…lol.



Rookie Answered on June 23, 2018.
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