Before checking the calibration on any gas thermostat, what should you check?

Before checking the calibration on any gas thermostat, it is essential to first verify the adjustment of the bypass flame. This is crucial because the bypass flame ensures that the thermostat operates correctly by providing a constant, minimal heat source to the sensing bulb. If the bypass flame is improperly adjusted, it can lead to inaccurate readings and affect the thermostat's performance. As a result, checking the bypass flame adjustment helps ensure that the thermostat will provide accurate temperature regulation, ultimately contributing to equipment functionality and safety.

While other factors, such as gas supply pressure, thermostat model, and equipment age, may be relevant in broader maintenance or troubleshooting contexts, they do not directly influence the initial calibration process of the thermostat itself. The accuracy of the thermostat's readings relies significantly on the proper adjustment of the bypass flame as the first step before any calibration efforts.