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10

Trouble-Shooting

Refrigerators & Freezers • Trouble-Shooting

The trouble-shooting guidelines below are arranged
sequentially and should be followed in order. Start with
“General Trouble-Shooting” A, B & C; then go to “Specific
Trouble-Shooting of Electrical Components”, starting with
“A” and working through systematically to “F”.

General Trouble-Shooting

A. Appliance Does Not Operate

Check that:

1. The thermostat is not set to “STOP” or “OFF”.

2. The electrical system circuit-breaker for the appliance is

“ON”.

3. The fuse between the electronic control unit and the

power source has not blown.

4. The power supply cable is not faulty, loose or poorly

connected.

5. The fan is operating and there are no blockages.

6. The battery is delivering sufficient power. If the battery

voltage is less than 10.4V (on a 12VDC system) or
22.8V (on a 24VDC system), the unit will not operate.

7. The voltage on the electronic control unit terminal board

corresponds to that of the battery. If there is a voltage
drop of over 0.2-0.4V check that:

a. The size of the cable connecting the battery to the

electronic control unit corresponds to specifications
(see Electrical Wiring Guidelines in this manual).

b. All connection points in the power circuit are

properly tightened and secure.

c. There are no signs of oxidation on the battery poles

or contact points and the battery is properly main-
tained.

B. Excessive Appliance Noise

Check that:

1. The appliance and refrigerating unit are positioned on

flat surfaces.

2. The appliance is not touching other objects that may

cause vibration.

3. The refrigerant lines at the back of the unit (if appli-

cable) are not touching or vibrating against the appli-
ance.

C. Insufficient Refrigerating Capacity

Check that:

1. The door/lid is sealed properly and the hinges are

working correctly.

2. The appliance is not positioned close to heat sources.

3. The appliance and remote refrigerating unit (if appli-

cable) are sufficiently ventilated.

4. Excess frost has not accumulated on the evaporator

(frost acts as an insulator).

5. Dust has not blocked the condenser ventilation sources.

6. The fan rotates freely (in forced air models).

7. The appliance is not over-full.

Specific Trouble-Shooting of
Electrical Components

A. Check Incoming Voltage

1. Hold meter leads to the “+” (the larger of the two “+”

symbols with the positive, red lead) and “–” (negative,
black lead) connections on the compressor module as
shown in Figure 1.0 and verify there is incoming power.
If not then check battery and/or alternative DC power
source(s).

2. Check that DC polarity is not reversed. If it is then

correct wire connections.

3. The inrush current must not drop more than 3% when

the compressor first comes on (per ABYC standards,
3% = 0.36 volts for 12VDC or 0.72 volts for 24VDC),
monitor volt/ohm meter at start-up. For 12VDC unit the

Figure 1.0 - Incoming Voltage

Summary of Contents for tundra

Page 1: ...Refrigerators Freezers Tundra Technical Manual Service Training Revised 10 22 03 L 2120 ...

Page 2: ... Electrical Wiring Guidelines Direct Current 6 DC Wiring Diagram 6 Refrigerators Freezers Operation Temperature Control 7 Rotary Thermostat Knob Control 7 Loading the Appliance 8 Refrigerators Freezers Maintenance Defrosting 9 Cleaning 9 Cleaning the Exterior 9 Cleaning the Interior 9 Cleaning the Condenser 9 Refrigerators Freezers Trouble Shooting GeneralTrouble Shooting 10 Specific Trouble Shoot...

Page 3: ...o allow compressor oils to settle NOTE Though we state on our packaging to always keep unit upright we cannot control how the carrier handles our boxes This also applies if unit has been set on its side to affix the bottom flange piece Carefully review all wiring diagrams included If you purchase a DC onlyTundra Unit simply wire your unit directly to the appropriate DC power source If you purchase...

Page 4: ...4 Installation Tundra Ventilation Requirements ...

Page 5: ...ailure fan overload and electronic unit overheating as well as destructive battery discharge When an overload protection is activated the compressor enters a cycle in which it makes start attempts at approximately 60 second intervals until a successful start is achieved Overload Protections The compressor overload and start protection cuts off power to the compressor if the compressor speed drops ...

Page 6: ...18 T22 Models use a 277 ohm resistor Electrical Wiring Guidelines Direct Current ABYC Guideline E9 below meets or exceeds Trucking Industry Standard SAE J1292 Conductor Sizes for 3 Percent Drop in Voltage DC Wiring Diagram ...

Page 7: ... Temperature Control Each appliance is fitted with a manual thermostat which automatically maintains set temperatures Rotary Thermostat Knob Control 1 Select desired temperature by means of the adjustment knob 2 The refrigerator is STARTED by turning the knob clockwise Temperature setting range is shown using a band that thickens in the clockwise direction The thicker the band the colder the setti...

Page 8: ... day On the rack under the freezer compartment Eggs 1 week Use door compartment Butter margarine 1 week Use door compartment Cooked food cakes and soups in sealed containers and cooled 3 to 4 days On the lowest rack in the refrigerator Cold cuts cheese fresh pasta pastries cream tomatoes puddings chocolates lard 3 to 4 days On any rack Fruit and vegetables 1 week In the bottom of the refrigerator ...

Page 9: ...ntire interior surfaces and then turn the appliance ON Cleaning Before cleaning disconnect the appliance from the power supply If necessary remove the plug from the power socket Cleaning the Exterior Clean the exterior with warm and then with cold water Dry with a soft cloth Avoid use of abrasive products Cleaning the Interior Remove racks containers and ice trays Clean the interior using warm wat...

Page 10: ...r contact points and the battery is properly main tained B Excessive Appliance Noise Check that 1 The appliance and refrigerating unit are positioned on flat surfaces 2 The appliance is not touching other objects that may cause vibration 3 The refrigerant lines at the back of the unit if appli cable are not touching or vibrating against the appli ance C Insufficient Refrigerating Capacity Check th...

Page 11: ...ck wire sizes against the Electrical Wiring Guidelines 2 Flashes Fan over current cut out The fan loads the electronic unit with more than 0 5 A avg or 1 0 A peak Fan may be blocked fan wires may be loose or damaged or the fan motor has failed and is drawing over current to protect itself Visually inspect fan for blockage check wires for chafes or loose connections and repair Or if fan has failed ...

Page 12: ...ontinuity at the thermostat then it should be replaced 3 If there appears to be no problem above then check the resistor that is connected to terminal T This resistor is used to set the compressor motor speed Connect ohmmeter to either end of resistor assembly Figure 5 0 This is a 277 ohm resistor verify that it is operating properly to spec with the 277 ohm resistor the control circuit current sh...

Page 13: ... fan then replace it F The Refrigerant Circuit 1 If the refrigerator seems to be running properly and passes all of the above tests and there is no cooling in the unit then the problem may be a refrigerant leak 2 Do not attempt to charge unit in field Contact your service dealer or Dometic Corporation at 804 746 1313 or 954 973 2477 Ask for the Tundra service department Figure 7 0 Fan Terminals Fo...

Page 14: ... are designed to move air through a heat exchanger by a blower or propeller fan This design necessarily produces a suction on one side of the air handling component and a pressure on the other side Air handling components must be installed so that the suction pressure action does not 1 pressurize an area to the extent that structural failure occurs which could cause harm to occupants or bystanders...

Page 15: ...Notes ...

Page 16: ...3227 0699USA 804 746 1313 Facsimile 804 746 7248 www tundra cc 2000N AndrewsAve Ext PompanoBeach FL33069 1497USA 954 973 2477 Facsimile 954 979 4414 FleetsIndustrialEstate 26WillisWay Poole DorsetBH153SU England 44 0 8703306101 Facsimile 44 0 8703306102 ...

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