I have a TH8000, a Heil DC90 furnace and an Amana heat pump. During the winter my daytime temp is 65 and at night I set it back to 55.

Everything has worked fine for the last 18 months until the last couple of nights (which have been cold but not remarkable). What happens is that at some point in the night the Thermostat resets to 65 and a message appears between the SET TO temperature and the "Following Schedule" which says "Emergency Override". I only detect this has happened when I wake up way too hot :-) but the last two nights this has been at 3:30 the first night and then 5am the second night.

I've checked the 0620 setting which is correctly set to 50. Is there something else I can do?

Here is all you need.

http://customer.honeywell.com/techlit/pdf/PackedLit/69-1894EF.pdf

Thanks for the file hvac1000 but I've read this and the installer manual and neither address the error I'm being thrown in the middle of the night. I can't find any reference anywhere to an "Emergency Override". Any insights for me or should I call Honeywell?

Thanks.

Call Honeywell.

I know why it says emergency override. You have a heat pump and you are using a setback schedule on it. That is a NO NO. To test my theory take the set back off the thermostat (REMOVE the setting and have no set back).

The reason for this is that the Honeywell has a auto safety set up. IE A heat pump takes a very long time to recover after a set back. The thermostat knows this and does a Emergency override of the set back so that the house will be at the proper temperature when it goes back to normal non set back temperature. I believe Honeywell calls it Intelligent Recovery.

Without this feature your house would never be warmed up when you woke up.
Call Honeywell and confirm.