measureQuick does not appear to calculate superheat and sub-cooling correctly, what’s up with that?
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- čas přidán 9. 09. 2024
- measureQuick does it the right way calculating average coil temperatures for saturation and condensing and using dew point and bubble point for refrigerant superheat and sub-cooling, This video explains why
Great explanation! Thanks Jim!
Thank you Jim, Keeping us on top.
Dank je jim goed werk :-)
On 410a, is condenser liquid temperature usually 20f higher than the outdoor temperature? And liquid line temp usually 10f higher than outdoor temp? Is that the general rule? Can you please direct me to where i can learn more about this?
What you’re talking about is called condensing temp over ambient, CTOA, And approach temperature. The condensing temp over the ambient varies with the type of condenser. Higher efficiencies have lower CTOA’s. A 13 SEER is typically 20° hotter than the outdoor air wear a 17 SEER is 15° higher than the outdoor air. Higher efficiencies have lower CTOA’s in general. The approach temperature is simply how close is the liquid line temperature to the outdoor air. Again higher efficiency condensers will have a lower approach temperature. That said the liquid line should always be at least 3° hotter than the outdoor air and typically always less than 10° high efficiency equipment. Refrigeration and air-conditioning technology, there is a chapter on “Typical operating conditions”. That is a good place to start
@@measureQuick wow thanks so much for the information. Love measurequick its the only app i use with my fieldpiece probes. Thanks again
Sorry Jim, this is not related to the video per se but I would love your feedback on this. The following happened yesterday, some context I’ve been doing this about 15 years and have performed easily over 100 evacuation by the book. Have you ever heard of or used refrigerant gas instead of nitrogen to break the vacuum for the triple evacuation? My boss have reprimanded me for using nitrogen. Explanation is that refrigerant gas is dryer. Feedback please? I’m begging you and I would love some science behind it if there is any.
With modern pumps, a triple evacuation is really not needed. You are better off with a single deep pull. The only reason to break a vacuum is if you have large amounts of moisture and you suspect that it has frozen, and you need to break the vacuum to stop the sublimation process. This is very rare, and likely only would be required for refrigeration applications or evacuations that were done in very cold weather.
Nitrogen and refrigerant have both been used for breaking vacuums. They are both very dry. The issues with using refrigerant is the environmental impact as well as the vacuum gauge is not calibrated for a refrigerant laden environment and it will read a false low, meaning that while it looks like it works better with refrigerant, it is actually only the refrigerant messing with the gauge. You can test this by hitting the sensor with a small amount of refrigerant vapor right out of the tank. The gauge will drop to 400-600 microns. This is because the gauges are thermal conductivity gauges and the refrigerant has different properties than the air/nitrogen it was calibrated for.
So sweep with nitrogen, pressure test, purge the nitrogen out to 1-2 psi and perform a single deep evacuation to 100-200 microns. Then do a decay test and assure that it does not rise above 500 in a 10 minute period for a typical residential system. For bigger equipment follow the manufactures instructions for the decay period.
Good info. Any ball park eta on the new testo gauges working with measure quick?
Already works with the Testo 550 & 557 - Live data streaming measurequick.com/tools/testo-digital-manifolds/
@@AndyHoltOutdoorUniversity Should have been more specific I guess, talking about the 557s.
Fieldpiece always makes you over charge system even in the newest SMAN with subcooling not right.
Like it👍
How often do the probes need to be calibrated
The probes cannot be calibrated, they should hold there accuracy for the lifetime (5 years is my guess for expected) After 5 years, I would recommend comparing them to a reference source to assure that they are still accurate. Pressure probes of all types can be zeroed. You can also offset the temperature probes. They have excellent long term stability.
Hi there again. Would target subcooling be the same if the outdoor temp is below 65f and indoor return is 65f as well or will subcooling be lower in that case?
No, subcooling will not change more then a degree or two under most conditions with the exception of a micro channel coil.
@@measureQuick thanks so much again
Jim I love you for all you do, but (there is always a but lol). Can you pleeeeeaaase change that when you hit the phones back button...... do I have to explain or I got many of you with me on this already 🤣. So many times I go into checking something then I want to go back to the previous page, I hit the phones back button (on Android) and it asks me if I wanna exit. Omg how many times did I hit exit by mistake, Jim the blood boils up at that point lol (feel my pain I'm in the hot attic or who knows where lol). Please for the sake of you know the thing, I beg you 🙏🏻. 🤣
When you say you want to “go back” does that mean to you go back to the previous screen or home?
@@measureQuick previous screen. Let's say I'm going in to check what my target SH should be, what values you give, then I hit the back button on the bottom (not the top, that does take me back) and it wants to exit MQ