Refrigerator Service Manual Models: DC440, DC451, DC490 DE441, DE451, DE461, DE490 MRFT415, MRFT440, MRFT460 NORCOLD, INC. P.O BOX 4248 SIDNEY, OH 45365-4248 Part No.
Trouble Shooting - Table of Contents -- Procedure A - Thermostat “ON” Compressor does not run ........................................................... 3 -- Procedure B - Compressor Resistance ....................................................................................... 4 -- Procedure C - Power Supply Output Voltage ............................................................................... 5 -- Procedure D - Compressor Amp Draw ...............................................................
Trouble Shooting - Procedure A Thermostat "ON" Compressor does not run NO Check Battery Voltage Short Circuit DC 5 V Power Supply Failure Change Power Supply DC 2 V Normal See Procedure B Measure terminal voltage of Temperature Control between TP1 & TP2 Is Temperature Control LED on? YES Wrong Correct DC Voltage Compressor runs YES (10.
Trouble Shooting - Procedure B Compressor Resistance Note: Perform procedure at room temperature. 0 Measure compressor resistance Internal Compressor Failure 3 +/-.5 Normal Change Cooling Unit See Procedure C ART01192 Turn the refrigerator to OFF. Remove the black wire to the compressor. Measure the resistance of the compressor bewteen Point A and Point B.
Trouble Shooting - Procedure C Power Supply Output Voltage Measure voltage between A & B at the compressor Below 15 V AC Power Supply Failure Change Power Supply 0 V AC Power Supply Failure Remove Power Supply Check F3 fuse on circuit board Ohms: Replace Power Supply & Cooling Unit 0 Ohms: Replace Power Supply ART01196 15 - 25 V AC Normal See Procedure D F3 Fuse B A A Figure 3 - Measuring Power Supply Output Voltage Figure 4 - DE Models only - F3 Fuse Location Figure 4A - DC Models only
Trouble Shooting - Procedure D Figure 5 - Measuring Amp draw of Compressor 6
Trouble Shooting - Procedure E Thermister Check-Out Turn the refrigerator to OFF to measure resistance of the Evaporator Thermistor. 1.6K - 29K Ω = good Thermistor. Disconnect the three pole connector (Figure 6) Measure resistance (Figure 7). Thermistor will stop compressor operation. Replace Thermistor. Ω = openThermistor windings. An open The Evaporator Thermistor is checked by measuring the temperature and resistance of the Thermistor (Table 1).
Trouble Shooting - Procedure F 8
Trouble Shooting - Procedure G 9
Trouble Shooting - Procedure H Auto-Shut Off Device Trouble Shooting Shut-Off Device WARNING Do not operate refrigerator with Shut-OFF Device disconnected. Operating the refrigator without device may cause compressor failure. To determine if Shut-OFF Device is functional, disconnect the Shut-Off Device from the Temperature Control. Connect the Temperature Control direct to power supply. IF refrigerator operates, replace the Shut-OFF Device. If no operation, replace the Temperature Control.
Trouble Shooting - Wiring Schematic 10 or 8 AMP Blade Fuse + DC DC 12-32 V - DC Red Battery In + Red Black DC Out Black Battery In - DC Out Orange AC - IN (L) White Converter AC - In (N) - + AC/DC AC 85-132 V + DC 24 V DC 24V Fan Motor AC/DC Part Red Black Compressor Fan Red Temperature Control + TP 3 F2 Fuse DC Input - DC 44.
Ventilation - Procedure I Ventilation is necessary for the correct operation of the refrigerator and to increase the life of the refrigerator cooling system. Ventilation allows the natural air flow that is necessary for good refrigeration. Cooler air comes in from the living area of the vehicle through a lower intake vent, goes around the refrigerator coils where it removes the excess heat from the refrigerator components, and goes out into the living area of the vehicle through an upper exhaust vent.
Ventilation - Procedure I In addition to the required vents sizes, a fan can be added to increase the refrigerator performance and to decrease the refrigerator current consumption . A fan kit is available through Norcold part distribution network. Refer to Fan Kit Assembly chart on page 12. 1. Side view of refrigerator 2. Ventilation Fan 3. Air Intake 4.
Ventilation - Procedure I VENTILATION REQUIREMENT CHART Refrigerator Model Min. Vent Sizes Without Fan Min.
Trouble Shooting - Quick Reference 1. Check for 12 VDC (supply voltage) at rear of the refrigerator. Turn refrigerator ON, operating voltage is between 10.5 VDC to 32 VDC. 2. Check for voltage (15 VAC-25 VAC) at compressor between points A and B. If voltage is not within range, refer to Procedure C on page 5. B A B A 3. Take an Ohm (2.5-3.5 Ohms) reading at compressor between points A and B. If Ohms is not within range, refer to Procedure B on page 4. 4. Take an Amp (1.5-2.
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