Ecodan ASHP idle / standby

[Itrium]

I have an ecodan ASHP running in WC with third party on/off thermostats connected to IN1 and IN6 terminals. When both thermostats are satisfied, the UFH pumps turn off as expected. The heat pump goes into idle mode but the pump to the ASHP itself keeps running and the water in this primary loop is kept heated by the heat pump.

It seems a waste of energy keeping this loop heated especially as the thermostats could switch off for several days in warm periods. Is this normal operation? If so, is there any way to switch off the heat pump besides manually turning it off at the controller?

I would be interested to hear if this is common to ecodans using third party thermostats or if there is some setting to turn off the heat pump when idle.

 

[PhilT]

Does this happen all the time or only at colder temps? I had this same issue at colder temps in the early days and it was the freeze stat setting which I turned off completely as I have antifreeze.

Edited January 3 by PhilT

[Itrium]

I’ve got the freeze stat setting turned off, set to **. At the moment the thermostats are set to close for turning off the heating. I was wondering if flipping the logic with the DIP switches so that the heat pump ran with closed thermostats would help?

[sharpener]

I imagine since this is easy to do you will have tried it by now.

 

Did it work?

[Itrium]

After much playing around, I believe this is caused by the room sensor settings in the initial settings. It was originally set to ‘Main RC’. The pumps on the two zones would turn off by the third party thermostats but leave the heat pump running. Changing this to ‘Time/Zone’ and setting the time to always on, allowed the thermostats to turn off the heat pump as well. Unfortunately the room temperature is monitored as -33’C.

The 2 zone configuration seems fairly common, Mitsu even supply a kit for this. Its a pity they don’t provide understandable documentation 😬