What is an acceptable condition for the heater resistance testing?

In heater resistance testing, it is important to measure the resistance of the heater under a range of temperatures to ensure proper functionality. An acceptable condition for conducting this testing is to perform measurements both below 40 degrees Fahrenheit and above 90 degrees Fahrenheit. This approach allows technicians to assess the heater's performance at extreme temperature conditions, which is critical in understanding how the heating element will operate in real-world situations typically faced in school buses.

Testing at extremely low temperatures (below 40 degrees Fahrenheit) and at high temperatures (above 90 degrees Fahrenheit) can help identify potential issues that may not be apparent at moderate temperatures. For instance, resistance values can change when temperatures shift outside this range, indicating a failure or inefficiency in the heating element.

By ensuring the heater is tested comprehensively across these temperature extremes, technicians can confidently evaluate the performance and reliability of the heater system.