Dometic Cooling Unit | NDA1402 | NDR1402

The Dometic cooling units NDA1402 & NDR1402 require the Fridge Defend by ARP for safety, reliability, and efficiency.


Table of Contents

Instructions: Subjects are listed on left. Click the link to the right to go directly to the subject matter on this page.

Instructions: Subjects are listed on left. Click the link to the right to go directly to the subject matter on this page.

Dometic NDA1402

Dometic 13.2 Cubic Foot Fridge

The Dometic 1402 series of fridge is found in Fifth Wheels and Class-A motorhomes. These fridges are no longer made, thus is is highly advisable to install the Fridge Defend by ARP on these units to insure a long life.

Please click here to see how the Fridge Defend by ARP protects your fridge.

Due to the heat that is generated by this particular cooling unit, we strongly advise using the Fridge Defend + Fan Control to increase the efficiency of the referigerator.

Click here to see how the ARP + Fan Control saves you money.

Dometic Thermal Sensor

ARP Sensor Install

This section shows the temperature sensor install on the models the NDA 1402 & NDR 1402. The procedures illustrated here apply to all of the Dometic left hand boiler fridges.

Please see Dometic Left Hand Boiler Temperature Sensor Install Video

The first step is to disengage the tab at the back side of the heater door access.

The green arrow shows where a screwdriver was used to bend up the corners of the tab. The red arrow shows the use of needle nose pliers bending the tab so that the bottom of the boiler housing can be opened.

Sometimes this tab is toward the back of the fridge, therefore not easily accessible. There are two methods to deal with this, one is to skip directly to the next step without disengaging this tab. In this case, aluminum HVAC tape can be used to reseal the access door, see images below.

The second method is to grab the boiler housing with both hands and twist the housing around to gain access to the tab.

Dometic Boiler Housing

To disengage the bottom of the door, cut a short slot - as shown by the red arrow. This slot allows the door to be disengaged from the cooling unit boiler housing by sliding the door to the right as shown with the green arrow. Please note that the door is disengaged in this photo.

Dometic Door Removal

This photo shows a Dometic NDA1402, the heater access door has been opened, the green arrow points in the direction to move the access door out of your way. The ARPrv temperature sensor has been clipped on the cooling unit boiler tube.

Please note that the sensor is above the electric heaters. The blue arrow points at the crimp in the Dometic cooling unit boiler tube. The ARPrv temperature sensor tip (red arrow) shall be in contact with the Dometic boiler tube. Restated, the temperature sensor tip shall not be straddling the air space created by the Dometic boiler crimp.

The manufacturer puts the crimp in the tube to hold the percolator tube within the boiler tube. Please see our How an Absorption Refrigerator Works to understand the basic principles of an Absorption Refrigerator.

Dometic 1292

After insulating the ARPrv temperature sensor and including extra insulation within the boiler housing, reverse the above order to shut the heater access door. Tape the bottom of the heater access door, as seen in this photo with HVAC Tape.

Click here to view the RM7030 page to see more ARP sensor install information.

Cooling Unit Wiring

The Fridge Defend installation requires a load relay for the 1402 that is not included in the installation kit.

NDA1402 (Two Methods)

Method 1) This wiring method controls the power to the fridge, click the following link for more information:
NDA 1402 requires a load relay due to the high amperage draw.

Method 2) This method requires a little more skill and a resistor to control the fridge by fooling the thermistor into turning off the fridge:
Alternate method using thermistor, no load relay needed.

ARP Fan Install

Please click here for the ARP blower fan and temperature sensor installation.

Please see the full User Manual and Installation Guide for more information needed before using your Fridge Defend control.

NDA 1402 Error Codes

Er 11 Heating element in frozen food compartment faulty.
Er 12 Heating element in refrigerated food compartment faulty.
Er 13 Heating element in drain pipes faulty.
Er 14 Fan in freezer faulty.
Er 15 Fan in refrigerator faulty.
Er 16 Air temperature sensor in freezer faulty.
Er 17 Air temperature sensor in refrigerator faulty.
Er 18 Temperature sensor (thermistor) on cooling surfaces in freezer faulty.
Er 19 Temperature sensor (thermistor) on cooling surfaces in refrigerator faulty.
Please click temperature sensor check.

Dometic Service Manual Repair Specifications

Please note that all of the following specifications are believed to be accurate. If any errors are found, please bring them to our attention as soon as possible. For critical specification please contact Dometic as they make changes to their specifications without notice.

FRIDGE MODEL: NDR1292 NDR1492 NDA1402 Units
ARP Control Boiler Temperature 185-195 185-195 185-195 Celsius
Off-Level Operating Limit dependent on ambient temperature
Minimum DC Power Supply 9.6 9.6 8.5 VDC
Maximum DC Power Supply 22 22 18 VDC
Maximum AC on 12VDC Supply Line 6 6 6 VAC


Board 12VDC Fuse 3 3 3 Amp
Board AC Fuse 5 5 5 Amp

AC Power

Operating Range 100-132 100-132 100-132 VAC

DC Heaters

DC Heater Power Rating -- -- -- Watts
Current -- -- -- Amps
Heater Resistance per Heater (cold) -- -- -- Ohms
Fuse -- -- -- Amps

AC Heaters

AC Heater (both heaters) 420 420 420 Watts
Current 3.5 3.5 3.5 Amps
Heater Resistance (cold) 34.28571429 34.28571429 34.28571429 Ohms

LP Gas

Gas Pressure 10.5-11.5 10.5-11.5 10.5-11.5 inch w.c.
Gas Jet #76 #76 #76
Gas Thermocouple 25-35 25-35 25-35 mili-Volts
Electrode to Burner Gap 3/16 3/16 3/16 inch

Fridge Temperature Sensor

Thermistor @ 33degF to 35degF 7k-10k 7k-10k 7k-10k Ohms

Please click here for more information on Dometic thermistor troubleshooting.

Dometic Service Manual Downloads

⇑ See above for troubleshooting info on this page ⇑

Service Manual Download: NDA1402, NDE1402, NDR1402.

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