Curlybonce Posted December 31, 2020 Share Posted December 31, 2020 We woke up this morning to no heating and 2 error messages on the Danfoss DHP AQ air source heat pump. The messages are Com Error HP Card and Com Error Exv card. I've looked it up on the internet and it says the HP Card error message is "Communication broken between display card and heat pump card (outdoor)" and the EXV card error is "Communication broken between display card and expansion valve control card (outdoor)" We've checked both indoor and outdoor units for any loose wires but there's nothing obvious. Does anyone have any suggestions as what we could do? Thanks Link to comment Share on other sites More sharing options...
ProDave Posted December 31, 2020 Share Posted December 31, 2020 Start with a full power down re boot, just in case it is a software crash? Link to comment Share on other sites More sharing options...
Curlybonce Posted December 31, 2020 Author Share Posted December 31, 2020 I've done this a couple of times and it still comes up with the same error messages. Link to comment Share on other sites More sharing options...
Curlybonce Posted January 9, 2021 Author Share Posted January 9, 2021 In case anyone else gets these error messages, the problem turned out to be mice had eaten through the communication cable outside that goes to the external unit. This has been replaced and it's all working now. 2 Link to comment Share on other sites More sharing options...
ProDave Posted January 9, 2021 Share Posted January 9, 2021 Thanks for letting us know @Curlybonce and glad it turned out to be a simple fix. Link to comment Share on other sites More sharing options...
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