Table 4-1. Direct Support Troubleshooting.
TEST OR INSPECTION
Step 3. Test for defective expansion valve.
Test for properly functioning expansion valve per para. 4-26.
Replace defective expansion valve.
If expansion val ve is not defective, replace compressor (see para. 4-28).
4. SUCTION PRESSURE TOO LOW.
Step 1. Airflow across evaporator coil is restricted.
Check for clogged evaporator coil. Clean as required.
Check for defective evaporator fan motor. Replac e if defective (see para. 4-12).
Check for clogged mist eliminator. Clean as required.
Check for clogged return air filter. Clean as required.
Step 2. Check for restricted dryer.
Step 3. Check for defective expansion valve.
Test for defective expansion valve. Replace if defective (see para. 4-26).
Step 4. Check for mashed or crimped refrigerant tubing.
Step 5. Check for low refrigerant charge.
Refer to servicing refrigerant system para. 4-6 and recharge system as