What is the recommended procedure for testing a float type LWCO?

The recommended procedure for testing a float type Low Water Cut-Off (LWCO) is to isolate and drain the LWCO to shut down the main burner. This method ensures safety during the testing process, as it allows you to confirm that the LWCO functions correctly and safely by simulating low water conditions. By isolating and draining, you are directly assessing the unit's response when the water level drops below the operational threshold, which is crucial for preventing boiler damage or unsafe operating conditions.

In contrast, increasing the pressure gradually might not accurately test the LWCO's ability to detect low water levels, since it's not directly related to the water level condition the action is intended to monitor. Opening all valves for inspection is not a focused test procedure for the LWCO and could introduce hazards without providing valuable information regarding the unit’s functionality. Calibrating the pressure sensor, while important for overall system accuracy, does not address the essential operation of the LWCO in response to low water conditions. Therefore, isolating and draining the LWCO is essential to ensure that it operates correctly under low water situations.