For the past 2 40+ deg. mornings when in heat mode there is a clicking noise coming from the outdoor compresor package. This sounds like a relay picking up and dropping out constintaly at about 3 second intervals. I have a similar second heat pump unit next to the problem unit. It is running fine and is NOT cycleing into defrost mode. This leads me to think it is not in the defrost circuit. I have not been able to get my wife out of bed these chili mornings to open the the access panel and start troubleshooting. When it happens next time my plan is to grab a flashlight and visually ck it out. Any sugg? Is there a manual available? Thanks.Scott. Please e-mail: scott.lang@aps.com