Manual
2 www.mastercool.com
HOLD will blink under the thermocouple temperature reading. The
pressure values can still be changed and the superheat or subcool
values will update. The thermocouple can be unplugged from the
unit and the temperature reading will remain. Turn the unit off and
the temperature reading will be lost.
To unfreeze the thermocouple temperature, press HOLD again or
turn the unit off.
To Change Units
1. With the Subcool/Superheat Calculator off, press the POWER
button.
2. Press and hold the ENTER button for two to three seconds until
the current temperature unit is displayed.
3. Use ▲ or ▼ to select the desired temperature unit.
4. Press ENTER to save. The current pressure unit will be
displayed.
5. Use ▲ or ▼ to select the desired pressure unit.
6. Press ENTER to save. The unit will return to normal operation.
To Update the Refrigerant List
CAUTION: This requires removing the back of the 52246 and
installing software on a PC. You will have to be connected to the
internet while updating the refrigerants. If you are not comfortable
doing this, return the unit to Mastercool to add the refrigerant(s) you
need.
System Requirements:
• PC operating system – XP or newer
• Memory – 4Mb Hard disk space
• Internet connection
1. Go to www.mastercool.com/pages/software_updates.html
2. Click on “Refrigerant Update Install Package”.
3. In the pop-up window, select RUN. The installer will download
and open.
4. A pop-up window will display stating: The publisher could not be
verified. Are you sure you want to run this software?
Choose RUN.
5. Follow the instructions to install the software. In the “Install
Complete” window, there is a check box. Uncheck the box if you
don’t want the downloader software to open immediately.
NOTE: a driver will be installed as well. If you get a pop-up window
asking for permission to do that, click YES.
6. A shortcut to the Mastercool_Refrig._Downloader software will be
on your desktop.
Alternative Method
1. Click on SAVE instead of Open in step 4 above.
2. Save the file to your desktop or somewhere you can remember
where you put it.
3. Double click on “Mastercool_Install_Package” to start the
installer.
4. Continue from step 4 above.
Prepare the 52246
1. Remove the battery
2. Remove the four screws in the back of the unit. (see Figure 1)