What device can be installed in a commercial A/C split unit to protect it from freezing

Don't bypass electrical contactors, replace it. Bypassing it will burn out the switch and possible cause a fire.

A switch or circuit tells the contactor to supply power and a solenoid smashed the double pole contacts together, 2 negatives and 2 positives. The switch doesn't carry the power, the contactor does.

It is a Protection Device

https://www.emerson.com/documents/commercial-residential/comfort-alert-diagnostics-for-commercial-applications-en-us-160794.pdf

https://climate.emerson.com/documents/comfort-alert-user-manual-en-2884458.pdf

There is a video here. I haven't watched it

https://www.google.com/search?q=Emerson+Comfort+Alert+Commercial+Diagnostics

Full list of Gree Air Conditioner Mini Split Units Fault Codes. When error codes appear on the Gree air conditioner indoor display, this tells the user there is an issue with the Gree AC unit. The error code displayed will inform you of the issue or problem that is occurring with the air conditioner. Knowing what the error code means and its definition will help you to understand and troubleshoot the exact Gree air conditioner part that needs to be fixed, cleaned, repaired, or replaced. You can then clean, fix, or replace the Gree part yourself and save money. See below for all error codes that can occur on Gree Mini Split AC's.
Gree Mini Split Air Conditioner Error Codes - How To Fix
Gree Viero AC Mini Split PDF Owners and Troubleshooting Manual
GREE DUCTLESS AIR CONDITIONING & HEATING SYSTEM INSTALLATION MANUAL

Gree Mini Split Air Conditioner Part Names and Locations
INDOOR AND OUTDOOR UNIT
The Gree Air Conditioning Vireo System has onboard error code diagnostics. The outdoor unit will provide status indicators and the indoor wall unit and remote control will display error codes. The following is a summary of the codes with explanations...
GREE AC DIAGNOSTIC ERROR CODES
Gree Vireo Mini Split Air Conditioner Error Code F0
Refrigerant Leakage Protection
1) Refrigerant leak(s).
2) Indoor coil temperature sensor not calibrated.
3) Refrigerant flow is restricted (ex. valve, exv, debris)
Outdoor Unit Red Light Indicator - 9 flashes and 1 sec Off
Gree Vireo Mini Split Air Conditioner Error Code E1
System High Pressure
1) Over charged with refrigerant.
2) Blocked or dirty outdoor coil.
3) Extreme outdoor ambient conditions
Gree Vireo Mini Split Air Conditioner Error Code E2
Indoor Anti-Freeze Protection
1) Low return airflow.
2) Indoor fan speed is too low.
3) Indoor coil is blocked or dirty.
Outdoor Unit Yellow Light Indicator - 3 flashes and 1 sec Off

Gree Vireo Mini Split Air Conditioner Error Code E4
Compressor High Discharge Temperature Protection
Please refer to the malfunction analysis (discharge temperature, overload) in service manual.
Outdoor Unit Yellow Light Indicator - 7 flashes and 1 sec Off
Gree Vireo Mini Split Air Conditioner Error Code E5
Overcurrent Protection
1) Supply voltage is unstable.
2) Supply voltage is too low and system load is too high.
3) Indoor coil is blocked or dirty.
Outdoor Unit Yellow Light Indicator - 5 flashes and 1 sec Off
Gree Vireo Mini Split Air Conditioner Error Code E6
Communication Malfunction
1) Communication cable is wired incorrectly between indoor and outdoor units.
2) Indoor or Outdoor control board malfunction.
Outdoor Unit Yellow Light Indicator - Continuous On
Gree Vireo Mini Split Air Conditioner Error Code E8
High Temperature Resistant Protection
1) Incorrect refrigerant charge level.
2) Refrigerant metering device malfunction.
3) Compressor malfunction.
Outdoor Unit Yellow Light Indicator - 6 flashes and 1 sec Off
Gree Vireo Mini Split Air Conditioner Error Code EE
EEPROM Memory Malfunction
Control board malfunction.
Outdoor Unit Yellow Light Indicator - 11 flashes and 1 sec Off
Gree Vireo Mini Split Air Conditioner Error Code C5
System Configuration Malfunction
1) No jumper cap inserted on the control board.
2) Incorrect or damaged jumper cap on control board.
3) Indoor and outdoor units are not compatible.
Gree Vireo Mini Split Air Conditioner Error Code Fo
Pump Down or Gathering Refrigerant Status
Optional Service Mode
Outdoor Unit Yellow Light Indicator - 17 flashes and 1 sec Off

NOTE: All of the Gree Air Conditioner Model Numbers below are applicable for the error codes on this page...
Gree AC Vireo Models: VIR09HP115V1A, VIR12HP115V1A, VIR09HP230V1A, VIR12HP230V1A, VIR18HP230V1A, VIR24HP230V1A, VIR30HP230V1A, and VIR36HP230V1A.
Gree Mini Split Air Conditioner Error Code Charts
Gree Mini Split AC Remote Control Button Names
Gree Mini Split AC Remote Control Icons Display Screen

Gree Mini Split Air Conditioner Air Filter Cleaning Procedure
Gree Viero AC Mini Split PDF Owners and Troubleshooting Manual
GREE DUCTLESS AIR CONDITIONING & HEATING SYSTEM INSTALLATION MANUAL
Need help with error codes on your Gree AC? Please leave a question below and we will be happy to help.

Low on freon, dirty evap, dirty filter or maybe restricted at the metering device

you'll have to be more specific in what you are attempting. Split systems are common place, but some are 220 vac some are 110 vac, some have remote controls, etc etc etc.... some have integral thermostats on the indoor unit, some do not and need an external thermostat, exactly what are you calling a 'motorcontroller'?

Hi there well it sounds like you got a R22 gas leak thats all

Depends what you are trying to record? Some TV stations have protection built in so you cannot record. If you are trying to copy a video from VHS to DVD and it's a commercial movie etc then it won't.
You can get a "box" that will get rid of copy protection signals, but only from outside the unit sources. Internal dub to dub protected sources cannot be copied.

How many times is the light blinking? Also is the light red, yellow or green? The light blinking is telling you exactly what has failed.
(# of RED blinks first)

1 High Pressure Protect
2 Indoor coil freeze protect
3 Low pressure protect

4 Compressor discharge protect

5 Low pressure/Overcurrent protect

6 Indoor-outdoor communication error
8 Hi-Temp protect
10 AC Voltage Low

Each of these has maintenance required steps to resolve the errror. Let me know how many blinks your getting...

Kelly

theunit is in freeze protection.what you need to do is hold the t-stat buld to bring the temp up and it will come back on shortly.dont unplug the unit.when it gets to cald it goes into freeze protection so pipes in house dont freeze

do you have a kink in that suction line?

ok, on these units, if by high side line you mean the small tube going from outside to inside, that tube is actually on the low side, the metering device is in the outdoor unit. If you shut the unit down, let everything thaw then restart and find that small tube is freezing up right at the outdoor unit right away, my guess is its low on charge. I see that you put some in, make sure it is the right knid of refrigerant. they do not hold alot. Where is your suction pressure running. If you put 2 to 3 pounds with no change, you may have overcharged but that is telling you that there is a restriction in the line inside the outdoor unit, probably the filter if it has one, or the metering device itself. Let me know what you find.