American Standard Thermostat Troubleshooting

Each table below is a troubleshooting manual for different models of American Standard thermostat: they cover all basic problems with devices and provide all possible solutions to solve the issues. With these tables, a user can check out what might have caused the malfunction, and fix it on one’s own. Please, note that some guidelines are general, and professional help can be required.

American Standard ACONT200AN11AA Thermostat Troubleshooting

ProblemCauseSolution
Display will not come on.1. Blown fuse or tripped circuit breaker.1. Replace fuse or reset breaker.
2. Furnace power switch OFF.2. Turn switch to ON.
3. Furnace blower compartment door or panel loose or not properly installed.3. Replace door panel in proper position to engage safety interlock or door switch.
4. 360 ohm resistor not installed.4. Install 360 ohm - 5 watt resistor
Display comes on and goes off.360 ohm resistor not installed.Install 360 ohm - 5 watt resistor
Temperature display is incorrect.Temperature display needs calibration.Calibrate Sensor
Cannot set Heating setpoint above 80 degreesDeadband between Heating and Cooling set to highDecrease Deadband setting
Service indicator Flashing on and off.Control EEPROM write error.Press any key and Check / Re-enter Setup Choices.
Service indicator solid on and in temperature display.Indoor temperature sensor open or shortedReplace Control
Temperature setting will not change. (Example: Cannot set heating higher or cooling lower).1. Upper and/or lower temperature limits were reached.1. Check the temperature setpoints:
2. "Keypad locked" is displayed on LCD.Heating limits are 40 - 85F.
Cooling limits are 65 - 90F.
2. Unlock keypad - press Up+Down arrow together until icon disappears.
Room temperature overshoots when Energy Savings Key ($) is used or the Heat/Cool settings is changed more than 2 degrees.Oversized heating or cooling equipment. Control can not respond fast enough to prevent overshooting.Set Control Response rate to "Fast"
Heating will not come on.1. System Mode not set to Heat.1. Set Mode to heat and raise the setpoint above room temperature.
2. Minimum off time delay being enforced.2. If heating does not come on within 5 minutes, Check Heating.
3. Loose connection to control or system.3. Check / Repair connections.
4. Heating system requires service or control requires replacement.4. Repair system / Replace control.
Cooling will not come on.1. System Mode not set to Cool.1. Set Mode to cool and lower the setpoint below room temperature.
2. Minimum off time delay being enforced2. If cooling does not come on within 15 minutes, contact servicer.
3. Loose connection to control or system.3. Repair connections.
4. Cooling system requires service or control requires replacement.4. Repair system / Replace control.
Cool ON or Heat ON is displayed, but no warm or cool air is coming from the registers.1. The heating equipment turns on the1. Wait one minute after Heat ON is displayed and then check the registers.
fan when the furnace has warmed up to a setpoint.2. Check Heating and Cooling system.
2. Heating or cooling equipment is not operating.
Control does not respond to keypad presses.1. "Keypad locked" is displayed on LCD.1. Unlock keypad - press Up+Down arrow together until "Keypad locked"
2. Keypad failure.2. Replace Control.
Fan does not operate properly in heat or cool mode.1. Incorrect wiring.1. Correct wiring.
2. Heating or cooling equipment inoperative.2. Repair system.
Fan runs all the time.1. Fan mode set to ON.1. Set fan mode to AUTO.
2. Shorted control wiring.2. Check / Repair wiring.
Cooling cycle too fast or too slow. (Narrow or wide temperature swing).The location of the control and/or the size of the cooling system may be influencing the cycle rate.Verify cycle rate adjustment
Heating cycle too fast or too slow. (Narrow or wide temperature swing).The location of the control and/or the size of the heating system may be influencing the cycle rate.Verify cycle rate adjustment

American Standard ACONT800 Thermostat Troubleshooting

Problem Solution
Some or all keys on the display do not work; why?Comfort control screen is locked
Comfort control is asking for heating or cooling to come on (screen shows "Heat On" or "Cool On" in display) but there is no heating or cooling runningCall your local heating and/or cooling contractor to check your heating and/or cooling system
Under the Fan on the screen, Auto and On or Auto and Circ are shown. What does this mean?The Fan is programmed for either On or Circulate.
Why doesn't the comfort control respond when I touch the keys?Check to determine if the screen is in the Locked or Clean mode

American Standard ACONT802 Thermostat Troubleshooting

SymptomPossible CauseAction
Display does not come on.Comfort control is not being powered.Check for 24 Vac between В and Rc.
Temperature settings do not change.The upper or lower temperature limits were reached.Check temperature setpoints.
Check Installer Setup Numbers 0600 and 0610; modify as needed.
The keypad is fully locked.Check Installer Setup Number 0670 to change keypad locked options.
Heating or cooling does not come on.Comfort control minimum off- time is activated.Wait up to five minutes for the system to respond.
System selection is not set to Heat or Cool.Set system Selection to correct position.
System type selection is incorrect.Check Installer Setup Number 0170 and make sure correct System type is chosen.
Comfort control is calling for Heat (Heat on) or Cool (Cool on) but no heating or cooling is running.Heating or cooling equipment is not operating.Check wiring.
Check Installer Setup Number 0170 and make sure correct system type is chosen. Verify operation of equipment in System Test mode.
Comfort control does not respond when touch areas are pressed.The keypad is locked.Check Installer Setup Number 0670 to change keypad locked options.

American Standard ASYSTAT 340 Thermostat Troubleshooting

SymptomPossible CauseAction
Display will not come on.Thermostat is not being powered.Check if the thermostat is mounted and latched on the wallplate-mount and latch the thermostat on the wallplate.
Check if the circuit breaker is tripped-reset the circuit breaker.
Check if the fuse is blown-replace the fuse. Check if the system switch is in the Off position-set to Heat or Cool.
Temperature settings will not change (Example: cannot set the heating higher or the cooling lower).The upper or lower temperature limits were reached.Check that the temperature setpoints are within range
Heating: 50° to 99° F (10° to 37° C) Cooling: 50° to 99° F (10° to 37° C).
Heating will not come on.No power to the thermostat.Check that the setpoint is above room temperature-reset temperature or wait for room temperature to fall.
System selection is not set to Heat. Heating setpoint is below room temperature.Check if the circuit breaker is tripped-reset the circuit breaker.
Check if the fuse is blown-replace the fuse. Check if the system switch at the equipment is in the Off position-set to Heat position. Wait five minutes for the system to respond.
Cooling will not come on.No power to the thermostat.Check that the setpoint is below room temperature-reset temperature or wait for room temperature to rise.
System selection is not set to Cool. Cooling setpoint is above room temperature.Check if the circuit breaker is tripped-reset the circuit breaker.
Check if the fuse is blown-replace the fuse. Check if the system switch at the equipment is in the Off position-set to Cool position. Wait five minutes for the system to respond.

American Standard ASYSTAT 570 Thermostat Troubleshooting

SymptomAction
Heating or Cooling will not come on.Check that the SYSTEM switch on the thermostat is set to Heat or Cool. Check if the circuit breaker is tripped—reset the circuit breaker.
Check if the fuse is blown—replace the fuse.
Check for air movement at the register.
Check power to the heating or cooling equipment.
Temperature setting is too warm or cool.Adjust the temperature by pressing either the ↑ or ↓ key.