In recent weeks, it has become apparent to me that the external temperature sensors on Nibe* heat pumps are very prone to the effects of the Orkney weather. The image to the right shows the internals of a typical Nibe outdoor sensor that is suffering from the ravages of the local Orcadian weather.
These sensors are critical to the correct operation of the heat pump and its failure can cause incorrect operation or total deactivation of the system as a whole.
My prototype control circuitry for a cheap proportional hydronic central heating diverter/blender valve is progressing well.
The MkI version worked well with just mechanical switches. Producing a valve which can be set and held in any position of its normal rotational path. This now allows me to produce a CT (Constant Temperature) valve and control unit for well under £100. A significant saving on current units,which sell for several hundred pounds.