这个系列的上篇和后记，提到我们的HeatPump热泵和Furnace电暖炉的两次故障维修。谁知，那还没完呢，因为三月底我们发现热泵又不工作了。短短时间接连坏，我们要求免费的测试找出真正问题。努力之外，YORK Distributor分销商，同意让之前安装新系统的Dealer 代理的师傅上面检查。

邪门的是，4月9号，师傅上门那天，刚进来，我调高了一下控制的设置温度，热泵就又工作了。这，我们试过多次，热泵从没启动过。他还是用仪器设备在外面的热泵检测了一番，又进来在控制器上操作一番，告诉我们啥啥都正常，走了。

可是一周多后，4月17号，我们发现热泵又不工作了。跟代理扯皮之中，4月23号上午，它又开始时不时启动，正常工作，直到4月28号，又不动了。继续和YORK的分销商联系，终于，他们再次让代理师傅上门。这次，又更换了控制热泵启动的传感器 liquid line sensor。同时，他也重新装了一条连接室内的Furnace和室外的热泵的新信号线signal cable。原来，上次他们来安装新系统的时候，居然直接用了原来那条、用过不知道几十年的老线，没有换新线！

信号线在太阳房下面过的那一段，外面看不到。不过，从两头能看到的地方的状态来看，应该是损坏得不轻的。这样一来，就很好解释控制器坏、传感器一坏再坏、和热泵时好时坏的现象了。

把最先跟分销商沟通的邮件主要内容，放这里做个记录。顺便也证明一下，我最开始的判断是有道理的 ：）

2021年4月5日，email to YORK Distributor

We started to have problem during January 30th 2021, no heat at all ! Only cold air came out of the vents. (The dealer’s) technician came on February 1st to fix this. He did some tests but to my knowledge he didn't check the Heat Pump that time. He found out that it was a faulty thermostat and he replaced it, and charged only for labor by about $186. Heat was back.

In late February, we noticed that the furnace was often working and discovered that the fan of the Heat Pump was not turning at all, regardless of that the weather was not that cold… They (the dealer) came on March 2nd to check and found out it was a faulty Heat Pump cable/probe called liquid line sensor. They changed it and charged us another $186.

For the first a few days afterwards, we closely monitored the heat pump and saw it working fine.  So, we did not pay more attention until in late March... Only on March 31st, we realized that the Heat Pump Fan was not turning again!

We called them on April 1st to report this, and let them know we are not satisfied having those problems with our new system consistently and having to pay for labor $186 every time! So, they decided to run some simple tests assisted by us ……. The heat pump started to work.

We monitored the heat pump during that day and it was working fine. However, the next day April 2nd, the Heat Pump stopped working again. So, we did the same reset as what's done the previous day, but this time nothing happened!

At this point, we want a technical expert to run a complete diagnostic free of charge (under warranty) for the whole system and find out what's really wrong to cause these breakdowns in such a short period of time.  For us, it seems that the heat pump itself is fine, but something in the system related to signals is wrong, which trigged thermostat and liquid line sensor's failure.