Fridge Optimizer Software Update

Firmware version Click here to download

Note! All units sold at Seattle Boat Show have version or higher. Check back here regularly for new updates!


  • Ability to switch between compressor models
  • New ‘Demo Mode’ added for showing graphs and data without a connection to a compressor or sensors
  • Humidity history is now based on hour averages taken from readings every minute (instead of once an h)
  • Fixed an issue with humidity history graph scaling
  • Fixed the incorrect scaling of the temperature history graph.
  • Fixed color inconsistency in temperature history graph
  • Minor stability and UI changes



  1. Download the software update file here.
  2. Save the file on the desktop of your Windows PC.
  3. Open the update.msi file on your desktop
  4. Windows will complain that it’s downloaded from the Internet…
  5. Select “I understand the risk…” and click “Run anyway”
  6. Windows will now point out the file is from “An unknown publisher”.
  7. Click “Yes” to continue.


  1. Power off the fridge and disconnect the Fridge Optimizer ethernet cable.
  2. Connect the Fridge Optimizer to the PC via a mini USB cable. The port is on the side of the unit, under a dust cover.
  3. Let Windows locate and install the drivers for the new “Serial Connection”.
  4. Open the Windows Start Menu and locate the “Fridge Optimizer Updater”.
  5. Select the COM port of the newly installed Fridge Controller.
  6. Press “Upload”.
  7. The application will say “Uploading…” followed shortly (20sec) by “27122 bytes uploaded”
  8. Done! Unplug the Fridge Optimizer from the PC and install the dust cover. Plug the ethernet cable back in and power up the fridge again. Enjoy!

Frequently Asked Support Questions

I'd like to install my Fridge Optimizer head unit away from my fridge/freezer. How can I do this?

The head unit can be installed up to 30ft away from the connector block. The installation is quite simple but you will need to buy a longer cable. The cable is a standard "40 Ft Cat 5e RJ45 Ethernet" cable. These can be bought for about $10-20 online or at the nearest computer store.

What is a normal compressor run time?

This depends on the system's design and environment it's operating in. Most marine compressors run between 20% and 70% of the time. Lower is better but sometimes higher is in some cases unavoidable depending on the system and the environment it's in (a large fridge/freezer combo with stock insulation in the tropics will likely run even more).

What are the best temperature settings from my fridge/freezer?

To answer this we must first determine a couple of things:



  1. Where the Advanced Thermostat is placed in relationship to the cold plate/holding plate: If the thermostat is placed very close to the holding plate your will need to lower these values as the temperature there will be colder than in the rest of the fridge/freezer.
  2. What type of cooling system you have: Freezer - this in itself can be broken down into a star rating (European system)
    1. [∗] : min temperature = Low:-5°C High:−3°C (23°F to 27°F). Maximum storage time for (pre-frozen) food is 1 week
    2. [∗∗] : min temperature = −12 °C (10 °F). Maximum storage time for (pre-frozen) food is 1 month
    3. [∗∗∗] : min temperature = −18 °C (0 °F). Maximum storage time for (pre-frozen) food is between 3 and 12 months depending on type (meat, vegetables, fish, etc.)
    4. [∗∗∗∗] : min temperature = −18 °C (0 °F). Maximum storage time for pre-frozen or frozen-from-fresh food is between 3 and 12 months. (This is what you need to keep ice cream hard)Note: A 4 star freezer has 3 inch or thicker insulation to run economically. If you run your 1 star freezer with these settings it will likely use a lot of power.

Fridge/Freezer Combo- Make sure the Advanced Thermostat is placed inside the refrigeration section, close to the cold plate. Set the temperature as you would for a fridge (starting with: Low:4°C (39°F) and High:7°C (45°F)) and wait 12h and measure the temperature of item inside both the refrigeration and the freezer section. If both sections are too high, lower the temp values by 2 degrees. If one section is too high and one is too low try to find a mechanical adjustment between the sections (an opening that can be partially blocked or an insulating piece that can be used to block the cold plate in the fridge section). Different manufactures use different solutions to vary the temperature difference between the sections.

Refrigerator- Try running the system with a Low:4C (39F) and High:7C (45F). Measure the temperature of items inside the fridge about 12 hours. If they are too warm, try decreasing both values by 2 degrees and try again. If it's too cold, increase the two values by 2 degrees and try again.

The screen is too dark. Is there a way to make it brighter?

Yes, press a button and the screen will light up fully for 2 minutes.The screen will go into a low power mode about 2 minutes after a button was last pressed. This serves two purposes. 1. The head unit uses almost 2/3 less power in the low power state. 2. The head unit isn't lighting up the interior at night.

My Fridge Optimizer says my compressor is running 100% (or close to 100%) of the time. Why is that?

There could be many reasons for this. The common thing is that the system is unable to reach the temperature you set as the low temperature cut off. The first thing you should try is to increase the low and high temperature settings in the fridge. They should never be above what's considered food safe temperatures! Here are some other common causes for this problem:

  • You just put warm items in the fridge/freezer and the system hasn't had time to cool those items down yet. Just let is work some more and check back in a couple of hours.
  • The temperature is set to lower than the system is capable of handling. This could be due to the system's design (cooling capability of the compressor and/or insulation thickness)
  • The system has frost or ice on the evaporator. Manually defrost it and then adjust the defrost cycle interval and defrost length. This may require a couple of tries to tune it right for your system.
  • There could be dust on the condenser, not enough air circulation around the compressor or the condenser, a plugged water line (if the system is water cooled).
  • There could be too little or too much refrigerant (R134a) in the system. This is most likely in cases when the system has been serviced recently or not serviced at all in many years.​Please ask a local professional for advice! If you want to learn more there are some really good blog posts about this topic by a gentleman called Richard Kollmann. 
My fridge is still frosting up after installing the Fridge Optimizer. What do I do to fix this?

Start by defrosting the fridge manually so the system starts from a good state. Then adjust the settings for the automatic defrost timer. Navigate to the settings page on the head unit and decrease the cycle time by 2 hours and increase the cycle time by 10min. Leave the system running and use it as normal for about a week. If frost has built up, decrease the cycle time by an additional 2 hours and increase the length by an additional 10 minutes. ​A thin layer of frost build up between defrost cycles is normal. Anything more than a thin layer of frost should be adjusted away as it otherwise decreases the efficiency of the fridge.

My fridge runs on AC power. How do I connect the Fridge Optimizer?

The Fridge Optimizer head unit is powered from the DC side of the Danfoss/Secop controller. You must provide 12 or 24 V power to the controller block. However, the fridge will draw its power from AC, if that is available via shore power/inverter. Note that you will need the AC-DC connector block, so make sure you order the correct model.

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