I have heating coolling units. I have 3 of them and can't get them to work F40 is coming up on everyone. PLEASE help asap

Sounds like it is a bit late for a blown fuse.
Call a heating engineer to repair it.

he is right. your installer must not have installed a backdraft damper.

If you need further help, reach me via phone at https://www.6ya.com/expert/thomas_092728000e6acb79

F.40 or f40 Miele cm5 coffee machine fault stuck at heating up phase this was resolved by using a different converter plug as the transformer in the power supply I had it plugged into was not carrying sufficient power to operate the machine I have a German imported machine and needed a converter 2 pin to uk 3 pin with 13amp fuse bought the converter from Amazon

There are some thermal sensor in the inside unit and out door unit which is used to measure the Coolling and compressor heat. If any one of the sensor is faculty then that error message will appear.
If you wish to get some more details about air-conditioner repair then check the following link
http://electro-medical.blogspot.com/

The "F40" fault code indicates a Cooktop Lockout error. There is a "Lockout" control board that locks out the cooktop from operating whenever the "Clean" cycle is used. It's not normal to display "F40" unless there is a "Lockout" or an "EOC" (electronic oven control) failure. It may need one or the other or both boards replaced. If the cooktop will operate after the range has cooled and unlocked then it may need the EOC and not the Lockout board. If you can ignore the beeping and the F40 and the range will heat up again in the clean cycle and complete the clean cycle then it could have a faulty Lockout board. Here a link to a YouTube video with the instructions on how to access and replace the EOC.

Here is the lockout board if you need to order it.
Here is the EOC board if you should need it also.

All parts come with a 365 day, any part, any reason return policy.

The F40 error code indicates a communication failure between the main machine control board and the motor control board for the blower motor on the dryer.

This can be caused by a loose wiring connection or a blown fuse.

This sounds like the thermal protection is activating. Make sure the vents and heatsinks have FREE AIRFLOW. If the sound cycles on and off, it could be a failure of the heater in the one vacuum tube in the unit. The heater could cooll and reconnect and then heat and disconnect.

I believe the unit you are describing is a heat pump. Heat pump are great when the temperature isn't below 30 With low ambient temps. outside it is much more efficient and comfortable to run aux. electric heat from the heat pump.

The EASY but Time consuming way (If you Only hagve USB 1), is to just RESET the unit.
The manual will run you through it, and reload.
I have both Gigabeat Room, and Win/Player 11, and have reset and reloaded a few times.
Just take some time (Specially with Gig Room)
Good Luck

Because bootloader found ,must copy again GBSYTEM