Bad ground and reverse polarity detection for HVAC controls

摘要

In exemplary embodiments, HVAC controls and corresponding error detection methods are disclosed. In an exemplary embodiment, an HVAC control generally includes a digital input configured to receive a digital signal, an analog input configured to receive an analog signal, and an error indicator. The control is configured to receive a neutral signal at the analog input, determine a voltage of the neutral signal with respect to earth ground, and operate the error indicator to indicate a normal state if the voltage is below a first threshold, a bad ground state if the voltage is between the first threshold and a second threshold, and a reverse polarity state if the voltage is above the second threshold.

主权项

1. An HVAC control comprising:
a digital input configured to receive a digital signal; an analog input configured to receive an analog signal; and an error indicator; the HVAC control configured to receive a neutral signal at the analog input, measure a voltage of the neutral signal with respect to earth ground, to operate the error indicator to provide a first indicator status indicative of a normal state if the measured voltage is below a first voltage threshold, to operate the error indicator to provide a second indicator status indicative of a bad ground state if the measured voltage is between the first voltage threshold and a second voltage threshold, and to operate the error indicator to provide a third indicator status indicative of a reverse polarity state if the measured voltage is above the second voltage threshold; wherein the first voltage threshold and the second voltage threshold are different, and wherein the first indicator status, the second indicator status and the third indicator status are different.