A heat pump dryer doesn’t really “heat” – it is more like a dehumidifier in a box.
If you have a current clamp then check the current to the compressor:
- if it sits at around 0.3 to 1.0 amp draw constantly then the compressor is running.
- if it spikes to roughly 10 amps for a few seconds before dropping to 0 (often with an audible click) then it is either mechanicaly locked up or the starter circuit isn’t working.
- if it doesn’t draw anything but there is voltage then check the cutout on the top of the compressor.
If it is running then after a few minutes there should be a noticable difference in the input and output pipes of the compressor.
Jem