Here are two of the most common thermal expansion valve problems experienced at supermarkets and some potential solutions for each. The subject valves previously had been operating at the correct superheat setting.
Problem: The valve will not feed enough refrigerant.
Possible solutions:
• Check the TEV adjustments.
• Check the sensing bulb location.
• Check for moisture.
• Check for contaminants in the valve body.
• Check for a solid liquid column to the TEV.
• Check design pressure drop for required TEV capacity.
• Check for element charge migration.
Problem: TEV continuously or cyclically floods the evaporator.
Possible solutions:
• Check the TEV adjustment.
• Check for a solid liquid column to the TEV.
• Time study the flooding cycles.
• Check the evaporator for airside heat loading.
• Check the evaporator for unequal circuit loading.
Source: Sporlan Valve Co.
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