What should be the normal liquid level in the high-level tank of the thermal oil heater?

The normal liquid level in the high-level tank (often referred to as an expansion tank) of a thermal oil boiler varies based on the specific design, capacity, and operational conditions of the boiler system. The primary purpose of this tank is to accommodate the expansion and contraction of the thermal oil as it heats up and cools down.

ZOZEN thermal oil heater YQL series

Here are some general guidelines:

Design Considerations: The manufacturer's manual or design specifications will provide the most accurate information regarding the optimal liquid level. It's crucial to refer to this documentation to ensure proper operation and safety.

Cold vs. Hot: When the system is cold (i.e., at ambient temperature), the tank should be partially filled. As the thermal oil heats up, it expands, and its volume increases, filling up more of the tank. Therefore, there should always be some allowance in the tank to accommodate this expansion.

Safety Margins: Typically, the tank shouldn't be filled to its full capacity when cold to prevent overflows or excessive pressures when the oil expands upon heating. Conversely, it shouldn't be too low either, as that can introduce air into the system or not provide enough oil for the boiler's needs.

Visual Indicators: Many tanks come with sight glasses or level indicators that provide visual guidance on the oil level. These indicators often have markings for minimum and maximum levels, helping operators maintain the oil within the safe operating range.

Regular Monitoring: Regularly monitoring and logging the liquid level in the high-level tank is essential. Sudden or unexpected changes in the level can indicate issues like leaks, air ingress, or problems with the thermal oil itself.

Other Systems: In more advanced systems, electronic sensors or float switches might be used to monitor and control the liquid level, providing alerts if levels get too high or too low.