7-4 Vogt
®
VT Service Manual
Troubleshooting
MACHINE “FREEZE-UP”
The following situations may cause machine “freeze-up”:
1. Harvest hold switch is improperly set
2. Improper fan control setting
3. Low head pressure limiting available gas for defrost
4. Dirty, scratched, or dented evaporator surface
5. Chopper motor or motor contactor defective
6. Interruption of electric service
7. Off on low pressure and reset without clearing tubes.
8. Low pressure safety switch improperly adjusted, causing termination prior to harvest.
9. Loss of water pressure.
10. Defective hot gas solenoid valve.
11. TXV not adjusted properly or functioning properly. Ice freezing too far up tube.
Note: If ice is freezing too high (onto the top flange holding the evaporator) the ice may not drop
from the evaoprator tubing. See page 8-6 for adjusting TXV.
Clearing a “freeze-up can be accomplished by placing “On/Off/Clean” selector switch in the “Clean”
position and circulating water over the tubes.
CAUTION: Clearing “freeze
ups” should be done using only water. Use of
any foreign objects (example: hammer or screw driver) may damage tube
surface. If tube is dented or scratched, ice will not release properly.
will void the evaporator warranty.