American Standard thermostat troubleshooting

American Standard ASYSTAT500C thermostat troubleshooting

SymptomPossible CauseAction
Display does 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 at the equipment is in the Off position—set to the On position.
Check wiring between thermostat and HVAC equipment— replace any broken wires.
If 24 Vac is present, proceed with troubleshooting.
Temperature setting does 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: Heating: 55 to 85?F (13 to 29?C) Cooling: 65 to 99?F (18 to 37?C).
Heating does not come on.No power to the thermostat. System selection is not set to Heat. Heating setpoint is below room temperature.Check that 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 On position.
If 24 Vac is present, proceed with troubleshooting.
Wait five minutes for the system to respond (thermostat displays Wait).
Set system selection to Heat.
Cooling does not come on.No power to the thermostat. System selection is not set to Cool. Cooling setpoint is above room temperature.Check that 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 On position.
If 24 Vac is present, proceed with troubleshooting.
Wait five minutes for the system to respond (thermostat displays Wait).
Set system selection to Cool.
System on indicator (flame=heat, snowflake= cool) is lit, but no warm or cool air is coming from the registers.Heating/cooling equipment turns on the fan when the equipment has reached the setpoint.Wait a minute after seeing the flame or snowflake and then check the registers.
System on indicator reads Filter and backlight is flashing.Filter expired.Refer to the Filter Indication section.
Outdoor temperature not displayed or is incorrect.Filter expired.Press B twice for outdoor temperature when filter expiration shows on display.
Installer did not activate this option. Outdoor sensor is connected incorrectly.Refer to the Filter Indication section.
Contact installer or service technician.
LED is lit.System switch is set to Em. Heat. Compressor failure.Move switch to Heat or Auto Contact service technician.

American Standard ACONT800 thermostat troubleshooting

QuestionAnswer
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. See the Fan Schedule section for more information
Why doesn't the comfort control respond when 1 touch the keys?Check to determine if the screen is in the Locked or Clean mode. See Screen Locked or Cleaning Comfort Control Screen sections

American Standard ACONT200AN11AA thermostat troubleshooting

SymptomPossible CauseAction
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
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.
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 the fan when the furnace has warmed up to a setpoint.1. Wait one minute after Heat ON is displayed and then check the registers.
2. Heating or cooling equipment is not operating.2. Check Heating and Cooling system.
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