If a tank only fills once and doesn't refill until the power is reset, where is the issue likely located?

The scenario describes a tank that fills only once and does not refill until the power is reset. This suggests that the system is experiencing a problem with the level sensing mechanism. A shorted long probe circuit can cause the level sensor to malfunction by continuously reporting inaccurate water levels to the control system. As a result, the control mechanism does not trigger the refilling process after the initial fill.

In many steam equipment systems, long probes are used to detect water levels within the tank. If the probe circuit is shorted, it may read the water level as sufficient even when it is low, preventing the refill valve from opening. This would lead to the observed issue of only one fill occurring until the entire system is reset, which clears the error state and allows a single refill.

Other potential causes, such as a faulty power supply, clogged water inlet, or dirty water filter, would manifest differently. A faulty power supply would likely prevent the operation of the entire system rather than just affecting the refill process. A clogged water inlet could prevent the tank from filling at all, not allowing it to fill even once. A dirty water filter might impact water flow but would not stop the system from recognizing that the tank needs to refill.