HVAC - Installing An A421 Digital Control In A Walk In Cooler
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- Опубліковано 10 вер 2024
- In this HVAC video, I replace an older A19 mechanical thermostat with an upgraded A421 digital control. The A421 includes many functions which include, Anti Short Delay, Sensor Offset for Calibration, Separate On/Off set points and more. On completion, I use the Testo 440 with 323 Air Quality Probe to verify. See some links below, Happy HVACing!
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Testo 440
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A421 Controller
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Good vid ! i used to use the a419 a lot. they got discontinued i guess. now i use the a421. i like them both a lot. i recommend u set your " asd " at 5 minutes for compressor short cycle protection. i put the probes in cooler evaps ( between the fins ) if u get freeze up problems. control by evap temp. off at about 15F ( somewhere between 10-20) on at 39. gives u a air defrost cycle every cycle.
Thanks for the comment. About the ASD, 5 minutes is too long for this application. It's a very small cooler, and opened often it also has sensitive products inside. When it needs to come it can't wait 5 ministers or there will be a deviation and that includes tons of paper work lol.
the anti short cycle delay does not work that way. it does not wait 5 minutes after it calls for cooling. the a421 is always counting how long it has been since it turned off. so, let's say it's been 4 minutes since the unit shut off and the temperature control is calling for cooling. the control will just wait one minute more so that the unit is not slamming off and on every 2 or 3 minutes. it just stops the unit from going on and off no sooner than every 5 minutes. compressor manufacturers actually want no more than six cycles per hour which is every 10 minutes. also check your setting for probe failure u want it most likely to fail cooling. i'm betting. so there's that too. " sf " should be set for "1" if u want it to fail cooling. or "0" if u want contacts open so unit does not run if that's more desirable for u. default factory setting is fail cooling or "1".
Great and thanks for sharing ! I still buy and replace mechanical thermostats for walk in boxes. Keep it up , sir.
@@OcRefrig yes okay, I gotcha. In my head I presumed it to be a delay on make to timer. But what you're saying makes more sense.
Same as a delay on break timer. as soon as unit shuts off timer starts counting.
Dude. Bad ass intro!
thanks man!
Hi I am working on draftbeer cooler on out side thermostat go to 40f the bartender say the draft beer is not cooling good
Paige are on 60f
The compresor is get off before to get a good cooling like 38 or 36
How can I get above 38 f on outdoor thermostat?
It manual Penn control Jhonson
Can I get down the thermostat? And how
Nice N.W Ohio & OcRefrigeration are here!
Subscribed
FYI when working on a low med temp its refrigeration work. HVAC/R that's what the R is for.
FYI, I'm well aware of that
Do you know how I can get it off of defrost ? For instance I’m service the system and it’s in defrost for another 30 mins and I wana get it off of defrost what do I do ?
Good video, Greetings from Panama
Do you have a photos for wiring without neutral wire? I have only black and red wires.
The diagram is available on the web, just Google it?
Nice work!
thank you!
Right hand drive? Nice video!!
haha, no, I'm using the camera on the front of the phone, it reverses the picture.
Is there a preference for calibration based off high or low temperatures? Better readings in cold or hot?
You only have to calibrate if the sensor starts reading incorrectly. Works great in hot and cold.
meads --- fyi those sensors are not immersion rated.
What's the difference between this one and the others 421 series
How to wire it?
According to the diagram in the manual
Like ranco better