On the front of the system is a light that they refer to as the heartbeat. Normally it will be a steady flash when everything is working correctly. In the event of a malfunction that flash will change to a pattern. If the issue is intermittent (or you shut the unit off/restart it) that code can disappear before someone can get out to look at it. So he told me if I ever experience a problem to write down the pattern just in case. When a technician arrives it will assist with figuring out and correcting the problem quicker.
On a side note, I've said this before in previous posts but I'll say it again. if you’re not getting your system checked out twice a year, in the spring and fall, start. I’ve been doing it for years and at least once in the past at my last house it caught an issue before it became a larger problem. With the company I use at least it also gives me priority service in the event of a problem. It's money well spent.
