Daikin Altherma HT Temperature Sensor Question - Caution: Mentions AI...

Air Source Heat Pumps (ASHPs)

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Marzipan71

(@marzipan71)

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Joined: 3 years ago

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Topic starter 19/11/2025 12:00 pm

Hi All - first post for a while, hope you are all well, and warm! I have a Daikin Altherma HT ASHP that uses an EKHWP-500PB thermal store - its a bit of a beast, at 500L capacity. Dimensions (and this is important) are 1660mm height x 790mm wide x 790mm deep. The unit uses a Daikin EKTESE2 sensor to measure water temperature. This is housed within a dry channel in the unit called a 'sensor pocket for tank temperature sensor' in the manual (link below) - i.e., it is not directly in contact with the water in the store. The thermal store creates temperature-stratified water - different from a regular water tank. Its built for solar thermal but I don't have the installed.

The water temperature sensor is clearly a crucial part of the system. The system was installed in 2020ish. I had very little faith in the installer and the relationship broke down to the point that we are no longer in contact. The sensor seemed to have been installed at an arbitary depth of around 80cm or so, so roughly half way down the thermal store. Its always bugged me that I could find no reference on the internet to a recommended depth for the water temperature sensor.

Enter AI! ChatGPT and Google Gemini have both told me - using reference to the exact model of the sensor and the manual for the thermal store - that the sensor should be put into the sensor pocket until it touches the bottom. That would be a depth of 135cm, which is quite different to how the installer (caveat above) had installed it. Both AI thingummies said look at the diagrams in the manual - the pocket is that depth for a reason, and it puts the sensor tip in the 'how water zone'. I can see the logic in this - it would make sense for Daikin to manufacture the sensor pocket to a depth that would correspond to a recommended depth for the sensor tip, no?

So - I'm no huge fan of AI and its talked rubbish to me about things I know about - so go easy on me bringing it into the conversation. But as I say, I can see the logic and I can't find anything on the internet about the actual Daikin recommended depth for the tank temperature sensor.

Does anyone have experience of the depth to which the temperature sensor should be installed?

Let me know if I've missed anything obvious here. Thanks for reading!

EKHWP300-500P(B), EKHWDH500B, EKHWDB500B, EKHWC500B, EKHWCH300-500(P)B, EKHWCB500PB_0081618744_05_0317_Installation and operation manual_English.pdf

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