你应该先查看一下你的系统有无自动切换功能。如果没有你，手动切换是可以的。只是别忘了切换回来。

从你的控制面板上看，当时heatpump 应该是处于停机状态，因为你设置为17度而室内是20度。二楼说的是对的，室外温度过低，heatpump的效率低下，如果系统没有自动切换功能，furnace 也会同时启动一会儿来补充（一般会有aux的字样出现在控制版）。其实留心一下，如果室外温度太低，且无自动切换装置，可人为的手切换成EM heat,这样只是furnace 起作用。等温度回升，再切换回来。

lscbaby 发表于 2017-1-4 12:14
it is normal that the external A/C gets iced in winter, but it does not affect the normal operation  ...

是 heatpump+furnance

it is normal that the external A/C gets iced in winter, but it does not affect the normal operation of the fan. The ice on the heat exchanger can not block the fan, because they are not touched at all. The ice just makes the heat pump work less efficiently. When outside is less than -10C, the heat pump will stop working, include the fan. This should be automatic, you can not do anything. I do not know in your house, the heating system is the combination of heat pump+baseboard or heat pump+furnace?

你这个是 heatpump 热泵，室外机的工作温度有极限的，在-7 到 -10之间。热泵不是使用加热管原理的，所以就算你使用，室外机一样需要运转。如果室外机一直有冰凝结，还阻止了风扇的正常运转，建议停用，不然容易打坏散热叶片。换成暖气片供暖。