Andyh747

Thanks, great suggestion. I have a few resistors but not enough to experiment. I’ll source some and do some experiments. 👍

See previous posts the sensor has failed. You could switch it on/off all day but unfortunately it won’t bring a failed sensor back to life.

It may have been on the way out but it’s now open circuit and heatpump shows unconnected so it’s failed completely now. I think I’ll just bite the bullet and buy a complete new sensor plus housing.

It's an MFT used for electrical testing. It goes from 0 to 999 Mohms. It's a Meggar 1741+ if you want to check the spec. Way more sensitive than a standard Multimeter.

See above. Tested with MFT. open circuit so definitely the issue. Now just need to source replacement. Can get whole unit from Europe but would be nice to just replace the thermistor.

Here's front and back of sensor. That's all there is to the sensor. The casing is just protection from elements and connector block. Photos attached.

Wiring already tested with MFT. The heatpump stats are constantly monitored. The outside temperature is reading 5 degrees and has been since the 8th Dec. Could be the heatpump interface but everything else is functioning. I'd like to test the sensor if possible but depends what type of sensor it is. I'll try and see if any writing on sensor. EDIT: In addition if the sensor is disconnected from the heatpump the heatpump reports an error with the sensor and the reading goes blank. So the sensor is providing valid connection to the heatpump but the value is not changing.

Yes see attached.

Hi All, I need to source a replacement sensor for this heat pump. Does anyone know what type of sensor this is and where a replacement can be obtained? Many thanks.

After a lot of effort I’ve managed to source replacement coils in the UK. A company called MJ Abbott Ltd in Wiltshire has them in stock. I’ve ordered two to keep a spare. I also ordered a replacement diffuser as the old one could do with changing. Just thought I’d update this thread in case anyone else ever comes across this issue and needs to source replacements. Thanks for the helpful comments and links provided.

Did you read my initial post? I've tested the coil with a resistance meter and swapped the coils around. It's open circuit on test.

That looks like it - great find. Pity I have to buy the whole thing though. Only need the coil. However if it's the only option then so be it.

Already tried that but the company which supplies these is Premier Aquatech but they've had to go back to the parent company in Germany and it's taking ages to get any information hence my post to see if anyone had a spare lying around 🤣

I've attached another couple of photos. One was taken while I was cleaning the manifold. If you need more let me know. It's a single base and each coil has a spring loaded valve which is normally closed to seal that port. When commanded the valve opens allowing air through the correct hose.

Yes but it is specifically designed to seal onto the manifold. There's a protruding ring on the base of the coil which seats onto the manifold. I can't find a match anywhere.