I had a new American Standard ACONT800 termostat installed. Our old thermostat had a settings for "system: heat, aux heat, cool, auto, or off" The new Amer Standard themostat has all but 'auto' for system. The manual says "auto, (if enabled). My question is, how do I enable it? can't find it anywhere on the internet

Google tcont800 installation manual. option530 should be 0 not 1. Press system button, 2 and 4 square hold until screen changes, option 530 --0

Had error code 91 on Trane XL19i thermostat. Heat season on duel fuel system. Repair tech said board is bad ($963) and transducer ($1000). Unit is 3 ton 12 years old. Does it make sense to repair or put in a new unit?

Could be cupel of reason #1 if you just installed new thermostat has to be programmed for two heat one cool heatpump. #2 you have lost a wire usealy white on w2 and black on E .or if you have a very old t-stat might be time to replace sounds like old t-stat

Well, if it wasn't doing that before then you more than likely know its in your wiring. Cools down then heats back up sounds like the auto change over is on, and the heat setting is higher than the cool setting?

Auxiliary Heat is used to turn the electric heat strips ON, If the heat pump is not working. Or if the heat pump can't bring the space temperature up to Set Temperature it will display Aux Heat ON....... Assuming you have a Heat Pump System with Auxiliary Electric Heat as Back up...... If the tech didn't install a jumper wire from AUX to W on the subase which is in back of the Display on the Thermostat.....you won't get Auxiliary Heat if the Thermostat is set for Auxiliary Heat. Other wise the thermostat will turn the heat pump on first and then the electric heat (Aux Heat) if it needs it to satisfy the set temperature....... Hope this helps

Wiring seems right, but it needs to be wired like the original tstat. Meaning if W was connected to w1 on the old, that's were it goes on the new. If it was on aux heat then your wiring seems correct. If its operating the aux heat "on its own", then that's were your issue is at.(?) Also, there is a configuration menu in the new tstat. It needs to be set up for your system, heat pump, 1 cool, aux heat or 2 heat 1 cool, O should engage the reversing valve(RV=O). If you didn't write down or pic what you started with, it will be tough for you, and us, to wire your unit correctly. And there is no factory installed fuse on the outdoor. The indoor will(should) have a 3 or 5amp "blade" fuse, (car fuse but not the new smaller style, the 80's to 90's style). Its on the indoor circuit board. Hope this helps!

Leave the factory jumper between R & RC. Connect the wires to the new stat just as you have them labeled. Use a piece of thermostat wire to make a jumper from AUX to E terminals. Your new thermostat should give you instructions on how to access the installer set up. You are going to set it up as heat pump with aux. I see this is 2 days old but if you need any help let me know.

Remove the cover of the circuit board and controls on the outside unit. Some units have a thermostat that allows you to set the temperature at which it switches to the second stage of heat. Set that for about 34 degrees.

I have a honeywell TH8320U thermostat and American standard Air handler with heating unit put in. THE thermostat works fine with the ac and follows the programs I have set. However the heat is a different story. The thermo clicks on to follow program but the unit does not run. (auto settings) If I place the thermo in heat and turn it to on I get heat?

You need to go into the installer setting to change it from heatpump to single stage gas heat.Go to www.honeywell.com if youve lost them.