Carrier VVT-1T System

The slave thermostat display shows four zeros that either blink on and off or are constantly displayed. This means the thermostat is repeatedly cycling through its power-up sequence and cannot enter normal operating mode.

A Comfort Trend (CT) error is a transparent error detected by the slave thermostat, indicating difficulty in maintaining the desired temperature conditions in its zone. The thermostat does not display this error directly; it must be accessed and cleared using the PC Command Center software. It signifies that the zone temperature is not improving or is worsening over time.

The slave thermostat may not correctly indicate equipment fan operation, the current system mode, or time of day. The system controller might fail to verify communications with the slave thermostat, or the thermostat operates continuously in setback or comfort modes despite proper configuration.

This is a configuration option (F11 on the rotary switch) that controls whether Hardware Failure (HF) and Storage Failure (SF) diagnostic error codes are shown on the slave thermostat's display. If set to OFF, error codes will not be visible.

The slave thermostat's 'HEAT' annunciator is on, and the LED on the HR-03 relay pack is also lit, indicating that the relay pack is receiving a signal. However, the corresponding supplemental heating equipment stage is not energized. This points to a problem between the relay pack and the heating equipment, or an issue with the equipment itself.

The slave thermostat's 'HEAT' annunciator is illuminated, indicating a heating demand, but the LED on the associated HR-03 Relay Pack is not lit. This suggests that the supplemental heat source is not being energized, potentially due to a problem with the damper actuator or the relay pack itself, despite the system controller calling for heat.

This error occurs when the slave thermostat attempts to open the damper blade but the position sensor does not indicate that the damper is in the full-open position. This suggests a mechanical or electrical issue preventing full opening.

This error means the slave thermostat is trying to close the damper blade, but the electronic position sensor does not register that the damper is in the full-closed position. This can be due to a mechanical issue or a sensor problem.

An HF31 error indicates that the zone temperature sensor is reading a temperature outside its normal operating range of 30 to 180 F. This could be due to a sensor malfunction, improper installation, or wiring issues.

This error occurs when the supply-air temperature sensor in the zone damper reads a temperature that is outside its normal operating range of 30 to 180 F. The system detects an extreme temperature, indicating a potential issue with the sensor or its environment.

This error indicates that the airflow sensor is reading a value outside its normal operating range. The specific cause can vary depending on whether a VS/ZVS-01 airflow sensor or a PS pressure sensor is installed.

These are Fatal Hardware Failure (HF) errors indicating a critical internal micro-electronic component failure within the slave thermostat. When either of these errors occurs, the slave thermostat completely loses its ability to control the zone.

These errors indicate a micro-electronic component failure, typically meaning the slave thermostat's printed circuit board has failed. The system cannot function correctly due to an internal hardware issue.

The slave thermostat does not activate supplemental or auxiliary heat even when there is a heating demand of 1.5° F or more. The 'HEAT' annunciator (indicator) is not shown on the display.

A Meter Full (MF) error is a transparent error indicating that the zone usage meter on the slave thermostat has reached its maximum recording value. The meter stops recording further usage until this error is cleared. This error is not displayed on the thermostat itself but is accessed and reset using the PC Command Center.

The slave thermostat display remains blank even after 24 VAC power has been applied. This indicates that electrical power is not reaching the slave thermostat or there's an issue with its power circuit.

A Storage Failure (SF) error, specifically SF 01, indicates that the slave thermostat's stored Device Address has been corrupted or lost. The system will default to address 63. This is a critical configuration setting that needs to be corrected.

A Storage Failure (SF) error, specifically SF 02, indicates that the slave thermostat's stored Comfort Set Points (Cooling and Heating) have been corrupted or lost. The system will default to 74°F for both cooling and heating. These settings define the desired temperature range for the zone.

A Storage Failure (SF) error, specifically SF 03, indicates that the slave thermostat's stored Setback Set Points (Cooling and Heating) have been corrupted or lost. The system will default to 85°F for cooling setback and 60°F for heating setback. These settings are crucial for energy-saving during unoccupied periods.

A Storage Failure (SF) error, specifically SF 04, indicates that the slave thermostat's stored Damper Maximum Open Position and Damper Minimum Airflow Position settings have been corrupted or lost. The system will default to 15 (max open) and 5 (min airflow). These settings control the physical operation of the damper.

A Storage Failure (SF) error, specifically SF 05, indicates that the slave thermostat's stored Supplemental Heat Damper Position and Damper Size settings have been corrupted or lost. The system will default to 0 for position and 4r for size. These settings relate to how supplemental heating affects damper operation.

A Storage Failure (SF) error, specifically SF 06, indicates that the slave thermostat's stored Comfort Set Point Limiting settings have been corrupted or lost. The system will default to 66°F (Cooling) and 80°F (Heating). These limits prevent users from setting temperatures outside a specified range.

A Storage Failure (SF) error, specifically SF 08, indicates that the slave thermostat's stored System Options #1 settings have been corrupted or lost. This includes critical options like Local Setback Control, Zone Pressure Independent Operation, and Zone Supplemental Heat. Defaults are mostly OFF.

A Storage Failure (SF) error, specifically SF 09, indicates that the slave thermostat's stored System Options #2 settings have been corrupted or lost. This includes options like High Torque Actuator, Damper Modulation, and Set Point Lockout Override. Defaults are mostly OFF.

A Storage Failure (SF) error, specifically SF 10, indicates that the slave thermostat's stored System Options #3 settings have been corrupted or lost. This includes options like PGC Setback Rotating Display and Minimum Ventilation Damper Position. Defaults are mostly OFF.

A Storage Failure (SF) error, specifically SF 11, indicates that the slave thermostat's stored System Options #4 settings have been corrupted or lost. This includes options like Setback Programming Lock and Meter Setback Override. Defaults are mostly OFF, except Rotary Switch Lock which is ON.

A Storage Failure (SF) error, specifically SF 12, indicates that the slave thermostat's stored Setback/Comfort Program schedule has been corrupted or lost. The system will default to a program of 6 a.m. (ON, M-S) and 6 a.m. (OFF, M-S). This schedule dictates when the system switches between comfort and setback modes.

A Storage Failure (SF) error, specifically SF 13, indicates that the slave thermostat's stored Zone Temperature Sensor Calibration value has been corrupted or lost. The system will default to a Mid-Range Value. This calibration ensures accurate temperature readings for the zone.

A Storage Failure (SF) error, specifically SF 14, indicates that the slave thermostat's stored Supply-Air Temperature Sensor Calibration value has been corrupted or lost. The system will default to a Mid-Range Value. This calibration ensures accurate readings of the supply air temperature.

A Storage Failure (SF) error, specifically SF 15, indicates that the slave thermostat's stored Airflow Sensor Error Correction or Pressure Sensor Communication (for SSP-01E) setting has been corrupted or lost. The system will default to a Mid-Range Value. These settings are crucial for accurate airflow and pressure monitoring.

A Storage Failure (SF) error, specifically SF 16, indicates that the slave thermostat's stored Airflow Set Point has been corrupted or lost. The system will default to a value of 0. This set point determines the desired airflow for the zone.

A Storage Failure (SF) error, specifically SF 17, indicates that the slave thermostat's stored Setback Override Time Limit has been corrupted or lost. The system will default to 60 minutes. This setting defines how long a setback override remains active.

A Storage Failure (SF) error, specifically SF 18, indicates that the slave thermostat's stored Comfort Trend Demand Set Point and Comfort Trend Time Limit settings have been corrupted or lost. The system will default to 0 for both. These settings are used for detecting and reporting Comfort Trend Errors.

A Storage Failure (SF) error, specifically SF 22, indicates that the slave thermostat's stored PS Temperature Sensor Calibration value has been corrupted or lost. The system will default to a Mid-Range Value. This calibration ensures accurate temperature readings for specific PS (Pressure Sensor) components.

A Storage Failure (SF) error, specifically SF 23, indicates that the slave thermostat's stored Airflow Sensor Error Correction (for SSP-01E) value has been corrupted or lost. The system will default to a Mid-Range Value. This calibration corrects readings from the SSP-01E airflow sensor.

A Storage Failure (SF) error, specifically SF 25, indicates that the slave thermostat's stored Device Security Code has been corrupted or lost. The system will default to a value of 0. This code protects device settings from unauthorized changes.

A Storage Failure (SF) error, specifically SF 27, indicates that the slave thermostat's stored 2400 Baud Rate setting has been corrupted or lost. The system will default to ON. This setting pertains to the communication speed of the device.

A Storage Failure (SF) error, specifically SF 28, indicates that the slave thermostat's stored Zone Usage Meter value has been corrupted or lost. The system will default to 0. This meter tracks the usage of the zone.

SF errors (SF##) are non-transparent errors that occur when the slave thermostat replaces invalid data in its memory with default factory values. While not fatal, the system controller will not use zone information from this slave thermostat to determine the system mode.