I am having an issue with our thermostat, not sure if anyone here has any suggestions.
Basically, the furnace responds to the thermostat only when it has dropped like 8C. We will set it at 22C on "permanent hold" (holds the temp 24 hours a day until changed), and the furnace won't kick in until hours later when the house drops to 15-16C and we're freezing. Then, it will stay on for a long time warming the (older) home up to 22C. It is supposed to be able to maintain a temperature within 1F so something is definitely not right.
I have been though the whole manual multiple times, I've tried setting schedules (which it doesn't obey, or starts to obey completely at random, or hours after the scheduled start/stop times), and I have tried the simplest "permanent hold" setting which it also doesn't seem to care about. The thermostat will display "heat on" but the furnace won't be running and indoor temperatures continue to fall.
The system is set to "heat" all of that is OK. When it finally signals the furnace to turn on, it works great and as expected. The furnace fires up, and a minute or so later the fans kick in and we get lots of heat from the registers.
Any idea why the furnace doesn't seem to want to talk to the thermostat? It's a fairly new Honeywell touchscreen programmable thermostat.