Altherma Flow Temp Issue Updated

[Jon Glanfield]

This is an update on an aged thread regarding some problems we had on an Altherma. Just briefly:

The initial requirement was sized incorrectly by Daikin from an over enthusiastic SAP
The single unit that we installed was half what was required
The original unit would never actually reach flow temp as per the setpoint regardless of whether WC or fixed set point was selected

Eventually Daikin agreed to provide a second unit FOC, we took responsibility for re-sizing and system design and in line with recommendations from here set up the 2 new units with a 500 litre buffer and separated the house control from the HP control.

The flow temp issue was traced to a damaged/inoperable thermistor which was changed out.

With 2 units the house which is 700 sqm with a revised heat loss of circa 21kw is now performing much better.

We have installed a meter on the incomer to the board dedicated to the heat pumps and currently it is performing 15% better than the predictions suggested by the Daikin software.

Many thanks to all who contributed to our understanding of the issue

[Brian_UK]

Many thanks for the update Jon.