Think you have a refrigeration repair problem with an expansion valve? Here are a few suggestions.
1. Proper Installation: Make sure that the valve is properly installed. It's amazing how often the little things matter.
2. Proper Superheat Adjustment: Checking the superheat by the book can be frustrating. There are easier ways.
3. Flooding Back: I once had an expansion valve flooding-back refrigerant to the compressor. The owner wasn't very happy!!!
4. Frost or Ice: On properly operating medium temp equipment you should never see frost or ice on the valve or distributor. (Of course this does not apply if you are working on a low temp system.) Things to look for?
5. Low Suction Pressure: Many times a lower than normal suction pressure can be caused by the valve. But other factors can be misleading.
6. No Suction Pressure: You can drive yourself nuts trying to figure out why there's no suction pressure. Yet there's plenty of refrigerant in the system. This is where I start.
7. Emergency Repair For A Quarter: Check out this emergency refrigeration repair I've used more than once to get myself out of a jam!!!
When I first started working in the field, I always dreaded expansion valve problems. Now it has become as simple as seeing, listening, and touching.
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