We have digital programmable thermostats in our house and have it set to 70 during the day and 65 at night yet it reads 75 all day and night. We end up turning off the system during the day. Does anyong know what the cause of this would be?? Is this an easy fix?? Something I can do??
Thanks

It sounds like the issue might be with multiple thermostats wired to one furnace. The way I understand it that can be done two ways: if they are wired in parallel then any thermostat calling for heat will trigger the furnace, and if wired in series then all must be calling for heat.

I won't attempt to try to troubleshoot this over the internet, but it should be easy to test by turning one all the way down and see if the other will control the temperature properly. It could be one bad thermostat or a mistake in wiring.

You have reached the limit of what I know about these things though. Myself, I would call a pro. Good luck!

There could be one of two things causing this.
one the thermostat is the wrong one for the type of system its connected to, or the Heat anticipator is incorrectly set.

The first one is a no brainer. Check the package that the controls came in to see if this device is compatable to your furnace and zone system.

The second one is a little tricky.
There should be, depending on the brand stat you purchased one or two screws on the thermostat, not the plate you screwed to the wall first but on the back of the control itself. This screw(s) can be turned one way or the other. When looking at the instructions for the thermostat you will see where they are located. This screw in simple terms pre-heats the thermostat to fool it into thinking that the room is warmer then it really is. Or anticipates the room temps. This in turn turns it off sooner. The end result is the room continues to warm up from the left over heat coming from the ducts or baseboard heaters and the result is the room does not overheat.
Each type of heating system depending on which type it is and what controls you have, have special settings in order to make the control work properly.

Also if you have zone control dampers on your warm air system most likely you will need to purcase the correct set back thermostat for the zone damper system that is installed into your home. The off shelf thermostats purchased at the big box stores most likely will not be conpatable to your system.

Zone damper systems can be tricky, As one zone calls and then turns off, the first thermostat may keep the zone open and allow for additional heat to enter that zone even if you do not need it, Thus the overheating of that area.

As far as incorrect wiring, I doubt that. If the system is turning on at all, most likely you wired them correctly it just the setting or not the correct (internal wiringing) thermostat purchased.Very common problem.