Manitowoc E07

What does Manitowoc E07 mean?

E07 indicates the thermal expansion valve (TXV) is starving — delivering too little refrigerant to the evaporator. The control detects this by comparing inlet and outlet temperatures of the evaporator; when the temperature differential exceeds 12°F in the wrong direction, it signals refrigerant starvation. The cause is either a restricted liquid line, a plugged TXV inlet screen, or a low refrigerant charge.

Symptoms

• Freeze cycles are excessively long before E07 triggers shutdown.
• Evaporator inlet temperature is much colder than the outlet during the freeze cycle.
• Ice slab is thin or forms incompletely before the fault logs.
• Suction pressure is lower than normal when gauges are connected.

Common causes

• Restricted liquid line filter-drier from moisture or debris contamination.
• Clogged TXV inlet screen blocking refrigerant flow to the valve.
• Damaged or failed TXV unable to meter refrigerant properly.
• Low refrigerant charge from a system leak.
• Previously opened refrigeration system introducing moisture or debris.

Diagnostic steps

1. 01

   Inspect the liquid line filter-drier

   Check for a temperature differential across the filter-drier with the system running. A notable drop in temperature across the drier indicates restriction; replace the drier and evacuate the system before recharging.

2. 02

   Check the TXV inlet screen

   If the refrigeration system has been previously opened, debris or solder flux can plug the TXV inlet screen. Recover the refrigerant, remove and clean the screen, or replace the TXV assembly.

3. 03

   Verify refrigerant charge

   Connect manifold gauges and compare suction and discharge pressures to the published charging chart for the current ambient temperature. Low suction pressure with clean components points to a refrigerant leak.

4. 04

   Check for refrigerant leaks

   Use an electronic leak detector or UV dye to inspect all brazed joints, valve bodies, and the evaporator for leaks. Repair any leak before recharging the system.

5. 05

   Replace the TXV if mechanically faulty

   If the inlet screen is clean and charge is correct but the evaporator temperature differential remains abnormal, the TXV itself is faulty and must be replaced. Recover refrigerant before removal.

When to call a professional

All refrigerant recovery, system evacuation, leak repair, and recharge work requires EPA 608 certification. TXV replacement involves opening the refrigeration circuit and must be performed by a licensed technician. Do not add refrigerant without first diagnosing the root cause.