Dead Expansion Valves?
No Refrigerant Suction Pressure?
Expansion valves die!!!
They shut down so tightly that you would swear the unit is out of refrigerant.
You connect your gauge hose to the low side of the commercial freezer and NOTHING!!!
No wonder the system is hot! You have a leak! Wow!!! Must be a huge leak!!!
Strange that all the refrigerant leaked out overnight.
You repaired the cooler unit yesterday and the freezer condensing unit was working great.
Nope. You can't see any obvious signs of a leak.
No broken cap tubes on the controls.
No oily areas on the equipment.
No sign of any rusting filter-driers. Strange!!!
Maybe the leak is inside the evaporator. Time to pressurize the system and begin looking.
You attach the high side gauge hose. To your surprise, the gauge needle jumps when you open the compressor discharge service valve.
There is plenty of pressure!!! But the low side gauge is showing nothing!
The unit is not out of refrigerant. It is off on the low pressure control.
If the commercial freezer uses a pump down system, maybe the thermostat is bad.
It's not opening the liquid line solenoid valve.
But the thermostat seems to be working. When you adjust the setting you can actually hear the valve opening and closing.
What about a restriction? Maybe a filter-drier? But you quickly forget that idea.
A filter-drier never restricts all the refrigerant.
It meters the refrigerant slowly.
There's also a temperature difference when you place your hands on each end.
Time to go into the freezer case. Time to check the last system part between the condenser and the evaporator.
The expansion valve!!!
What do I look for? What could cause the above scenario?
Chances are, you have a dead power element!!! For some reason it has lost its charge.
What causes it to lose its charge?
Carefully look at the cap tube connecting the power element to the sensing element.
I'll bet you'll find it broken.
Excess unit vibration shakes the tube until is snaps.
It must be secured. A dab of silicon applied to the evaporator and the cap tube works great.
What's that? You checked the cap tube and it's OK?
Guess you are going to have to disassemble the valve.
I have never found debris completely shut off the refrigerant flow.
Forget the small trash you find.
Instead, remove the power element completely.
Shake it!!! Does it rattle?
If so, it's dead!!!
You can also stick you finger into the head and easily move the diaphragm. Not good!!!
Replace it!!! You should be ready to go!!!
Remember!!! Secure that cap tube on all the expansion valves!!!
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