Monitoring Legionella Cycle on Ecodan

Hi All,

I’ve just started monitoring my Ecodan setup and am slightly confused by the data when the legionella cycle is running.

I’m not seeing the Tank Temperature go above 50 and there’s no appreciable increase in electricity consumption.

I’m wondering if there’s something wrong with the immersion… Do you guys see spikes when the cycle is running?



Hello Chris

Ecodan’s have the immersion heater connected via a second supply. There should be a second mains cable that goes into your indoor controller which is then switched by a relay in the main controller before going to the immersion heater.

Does your monitoring on the Ecodan include that separate supply? Is it even wired in? I’ve seen one installation where the immersion heater was wired in to the main controller but there was no secondary supply connection connected - and so when the relay would switch on/off it wouldn’t do anything…

Note: Immersion heater should be connected independently from one another to dedi-cated power supplies. and the diagram showing this separate supply below:

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There’s a separate supply and two fused switches on the wall with two wires coming into the control unit.

Interestingly, they were both switched up (in the traditional off position) when I just checked. I’ve set the cycle to run at 11:00 so will see what happens then.

Do you know why there would be two wires here?

Im not sure, booster heater, pumps on seperate supplies? any labels?

Unfortunately not… However, I believe I’ve gotten to the bottom of the problem.

It seems the reset button had popped on the immersion heater. Resetting it and I’m now seeing heat and power recordings.

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