Effect of disinfection function on Daikin heat pump

Our heat pump has functionality to disinfect the boiler (hot water tank) on a weekly schedule. I wanted to understand how much energy this consumes and how long this takes.

Test setup

• Daikin heat pump
• By default our hot tap water in the tank is set to 45 degrees Celsius
• Energy meters:
• 1 main meter for the overall house consumption (red graph)
• 2 sub meters measuring for the heat pump installation (1) the outdoor heat exchanger and (2) the indoor boiler. (yellow and blue graphs)
• Heat pump user interface with Advanced user enabled
• The test was done mid-October with an average outside temperature of 7 degrees Celsius

Test background

The disinfection was scheduled to start at 19:00 and the disinfection temperature was set to 60 degrees for a duration of 40 minutes. All of these parameters can be edited through the installer settings.

Test results

The graph clearly shows that the outdoor unit consumes energy (between 2300 and 1700W) first to start heating the incoming water up to 60 degrees from 19:00 until 19:40. From 19:34 onwards, the boiler itself consumes energy (4100W down to 3000W) to further heat the water inside the boiler up to 60 degrees Celsius until 20:18.

Summary

The heat pump consumes on an average 5-7kWh per disinfection that lasts roughly 80-90 minutes. The total estimated consumption per year is in between 250-350kWh.

Changing the parameters or disabling the disinfection function of a Daikin Altherma heat pump

In order to save on my energy consumption, I decided to disable the disinfection function of my Daikin Altherma heat pump. By default this function is enabled to run once a week at Friday evening. The purpose is to heat up the hot tap water boiler to a preset temperature during a certain amount of time, so that bacteria that can start to live in your boiler will be cooked to death. When speaking to Daikin, they told me that this function could be disabled, as long as you use daily or very regular hot tap water by showering e.g.

To understand how much energy the disinfection consumed, click here.

Steps to disable the disinfection function

1. Change the user level to installer. Steps can be found here.
2. Press the Back button and Navigate to the Installer Settings (Installateurinstellingen) and press OK.

3. Navigate to Hot Tap Water (Warmtapwater) and press OK.

4. Navigate to Disinfection (Desinfectie) and press OK.

5. To disable the disinfection, select Disinfection (Desinfectie) again and press OK. When asked to disable the function, change Yes (Ja) to No (Nee) via the Navigate buttons. The confirm by pressing OK.

6. Press the Back button. You are being asked to restart the heat pump. Press OK to confirm. The display will reset itself and show a message Busy (Bezig) and restart itself. Note the wrench symbol that indicates that we still have installer as user level.

7. Now you have disabled the disinfection function. Alternatively, you could also change the parameters so that the function runs during the afternoon (instead of 11pm), when there's more heat in the air to exchange into water.