TM9-4120-401-14
Table 4-2. UNIT TROUBLESHOOTING - continued
MALFUNCTION
TEST OR INSPECTION
C O R R E C T I V E ACTION
REDUCED COOLING CAPACITY. - continued
5.
Step 9. Check operation of potentiometer TEMPERATURE control.
Test potentiometer TEMPERATURE control. (See paragraph 4-27.) Replace control if
defective.
REDUCED HEATING CAPACITY.
Step 1. Check that all doors, windows, and other openings in the room or enclosure are tightly closed.
Tightly close all openings.
Step 2. Check setting of potentiometer TEMPERATURE control.
Set control to fully WARM; then, if condition improves, adjust properly.
Step 3. Check that the louvers in the conditioned air intake and discharge grilles are properly adjusted.
Adjust louvers properly.
Step 4. Check to be sure that excessive cold, outside air is not being introduced through the fresh air
damper.
Fully close damper; then, if condition improves, adjust properly.
Step 5. Check airflow out of conditioned air (evaporator) discharge grille. If airflow volume is low:
(1) Adjust conditioned air (evaporator) intake grille louvers.
(2) Clean and service, or replace conditioned air filter element. (See paragraph 4-18.)
(3) Clean and service, or replace mist eliminator. (See paragraph 4-20.)
(4) Clean evaporator coil and entire evaporator section. (See paragraph 4-47.)
Disconnect input power before performing internal electrical troubleshooting.
Voltages used can be deadly.
Use disconnect switch (NOT POWER CABLE) to disconnect power to unit.
Damage to cable connector pins will result if cable is used.
Step 6. Check for loose or damaged wires and terminals.
Tighten loose or damaged terminals. Repair or replace damaged wires. (See
4-29
