Check High Temp Thermostat
refrigeration
Description
With the Main Power switch out of OFF, the EVHTS circuit is open; the unit alarms and no heat is allowed.
Activation Conditions
With the Main Power switch toggled out of the OFF position, the EVHTS circuit is open.
Unit Behavior
Engine and Electric Operation: Alarm AND no heat allowed.
Reset Conditions
Auto Reset when the EVHTS circuit is okay for 15 minutes, or alarm may be manually reset via keypad or by turning the unit off, then back on again.
Corrective Actions
1. Check Evaporator Area For High Temperature - Check Evaporator temperature using a test thermometer. EVHTS opens when the temperature of the evaporator becomes very high (Refer to Section 2.11). (For example, if the heaters are on when the fan is not running.) If the temperature of the evaporator section is very warm (hot), it will have to cool down before the EVHTS closes. 2. Check High Temperature Thermostat (EVHTS) - Inspect thermostat and connector. (See wiring schematic Section 10.3) Check for damage to the thermostat. Verify no damage or corrosion in connector. 3. Check High Temperature Contacts Contacts must be closed when temperature is normal. Unplug EVHTS and check for continuity. Must be 0 (zero) Ohms. Cannot be opened (infinite ohms) or shorted to ground. If HTT is open below temperature, (Refer to Section 2.11) replace HTT.