Honeywell 7-Day Programmable Thermostat

My heater stopped responding to this thermostat. I noticed the print on the display screen was a little dim so I replaced the batteries. The screen looked much better. I thought the issue may have been the batteries; however when I got home it was 50 degrees fahrenheit despite the thermostat being set to 66 degrees fahrenheit. The display screen shows "Heat on" yet the heater is not activating (the pilot is lit, I checked). This thermostat was already installed when I moved in, I do not have the original manual. Is there some sort of pairing procedure or perhaps a step that may not be obvious that I may not have done after replacing the batteries? It's mid winter and my daughter and I have been without heating for a week now. I don't have money to replace this thing right now and really need it to work. Any help or ideas would be greatly appreciated, thanks.

Here I am at 5:00 writing this review (when I shouldn't be awake) because of how terrible the programming on this thing sucks. My sleep time is set for 10:00pm @55 degrees, my wake up time is set for 8:00 am @74 degrees. Why is it that at 4:30-5:00 (3-4 hrs before set wakeup time) the heat is at 74 degrees. Mind you this ain't the first time this has happened, I tried resetting, I've tried setting new times/temperature but it still doesn't seem to help. Moral of the story is if you want to be able to stick to your regular sleep schedule or even try to relax and be comfortable in your own home then don't buy this piece of junk!!!!!

Worse thermostat ever! Whoever invented this needs to apologize. Programming is a nightmare. Move on, hits desired temperature, fan keeps running pushing cold air. There is a temperature set somewhere in the memory of 63. Like clock work at 7am that sets. I have no idea why. I have run through programming to many times to count, cannot find this set an. Like clockwork 7am 63. It's 0 degrees outside! Making me insane

Bought this thermostat a couple of years ago as a replacement for one that was defective from the start. This is used for the heating system at our vacation property. Arrived there yesterday and found the heating system off with a blank screen on the thermostat. I removed the thermostat and replaced the batteries that were down in voltage. The screen came back to life but I never re-installed it as this should not happen when the batteries get low. Batteries should be there only to retain memory in the event of a power failure. 24 volt control power was always present. I temporarily installed an old mercury bulb thermostat to get the heating system running. I have had a similar thermostat where I live for probably five years or more and have had no issues. I am a retired HVAC mechanic and used Honeywell almost exclusively so am somewhat disappointed.

What my previous thermostat did was if I set it at 70 degrees, on heat & auto fan, hot air would come out until 70 and stop. Then, if the temp drops below 70, the hot air would turn on again to bring it back up to 70. With this one, when I do the same, hot air comes out until it gets beyond 70 and then cold air starts coming out to bring it down to 70; it's constantly running the fan. There's no point of choosing heat and auto.