Minnesota Special Engineer Boiler License Practice Exam

What action can be taken to remedy a water-logged expansion tank?

1. Drain it completely

2. Replace it

3. Check air levels and recharge

4. Install a new regulator

The correct answer is: Check air levels and recharge

When addressing the issue of a water-logged expansion tank, checking air levels and recharging the tank is the appropriate action to take. An expansion tank is designed to absorb excess pressure caused by the thermal expansion of water in a heating system. It typically contains a bladder or diaphragm that separates air from the water, which allows the tank to function correctly. If the expansion tank becomes water-logged, this indicates that the air pressure has diminished, which can result from water entering the air side of the tank. By checking the air levels, you can determine if the pressure is too low. If it is, recharging the tank by adding air will restore its proper function, allowing it to effectively absorb pressure fluctuations in the system. Draining the tank completely would remove both air and water, which doesn't address the underlying issue of air pressure balance. Replacing the tank can be unnecessary and costly if the problem can be remedied through simple maintenance. Installing a new regulator does not directly address the specific issue of the water-logged tank, as regulators are more concerned with controlling pressure in the system rather than managing the air-water balance in an expansion tank. Therefore, checking air levels and recharging is the most effective and efficient solution to rectify the water-logged