RM3762 | DMR702 | DMC702

If you want to increase reliability, safety, and efficiency of your RM3762, DMR702, or absorption type DMC702, install the Fridge Defend by ARP.


Table of Contents

REQUIRED TO DOWNLOAD INSTALLATION INSTRUCTIONS - WEB PAGES ARE SUPPLEMENTAL - EACH VERSION OF CONTROL HAS INTRICACIES REQUIRING THE WRITTEN INSTRUCTIONS.

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


Dometic Recall

Dometic RM & DMR 7 Cubic Foot Cooling Units

The Dometic 7 cubic foot fridges are very efficient and economical as long as they are operated correctly. All absorption type refrigerators are susceptible to corrosion and then failure of the boiler unless the boiler is protected properly.

The Fridge Defend is a necessity to keep these fridges safe, reliable, and efficient.

Click here to see how the ARP helps prevent fires while improving reliability and efficiency.

This image shows the cooling unit compartment of a typical Dometic. Please note the 'Thermofuse' (Boiler Housing Thermal Switch). This snap disk type sensor will turn off the fridge if one of two conditions occurs:
There is an extreme over temperature in the cooling unit compartment, or there is a fire. Either failure mode results in the destruction of the cooling unit.

Please click here for further reading on the 'Thermofuse', search the key word 'thermo-fuse' within this document.

Also, see Error Code section below for more info on the thermofuse (also referenced as: Thermal Fuse, Thermal Switch, the original recall device).


ARP Control RTD Sensor

Install Boiler Sensor

This photo shows how the Fridge Defend sensor can properly manage the boiler temperature. This photo shows either an RM3762 or a DMR702 boiler assembly. Note, the Dometic 'Thermofuse' is outside the insulated housing, thus the thermofuse cannot sense the actual refrigeration process boiler temperature. Note the yellow arrow points to the proper location to install the Fridge Defend sensor. The flue tube is behind the yellow arrow tail. The green arrow points to the boiler tube, this is the proper location for the ARP temperature sensor.

WARNING: The temperature sensor must not be on or touching the flue tube, this will void the temperature sensor warranty. Insulation must be placed between the flue tube and the temperature sensor.

ARP Boiler Sensor Install

Click here for temperature sensor install video.

Click here for temperature sensor install photos and insulation.


RM3762 Cooling Unit Wiring

Control Location

This drawing shows the typical location to mount the Fridge Defend by ARP control box. Because the Fridge Defend is automatic once setup, we recommend mounting the controller in the cooling unit compartment. The ARP shown has been mounted on the Dometic controller housing, please see information below for wiring.

DMR702 & DMC702 Error Codes

The following table shows the fridge error codes. The right column shows the control panel 'temperature setting' LEDs that flash the error codes. Once one has successfully troubleshoot the problem and repaired, turn off the fridge and turn back on to reset the display.

ERROR CODE . MEANING
DMR702 LP Gas Falut Code . There is an error in the LP Gas system. Check gas pressure, gas valve, flame igniter, fuses.
DMR702 Thermistor Falut Code . The thermistor (temperature sensor) inside the fridge has an error. See troubleshooting section below for thermistor resistance. Check electrical connections.
DMR702 12 Volt Falut Code . The fridge supply voltage is out of the range 8 to 18 VDC. Use DMM to measure the supply voltage to the fridge. Check voltage at 'terminal block' as seen in first image on this page. Check ground connection to battery.
DMR702 Thermalfuse Fault Code . The boiler housing thermal switch is open. This device will never trip if the ARP Control is monitoring the boiler temperature. If this 'thermo fuse' trips due to the boiler overheating, the fridge has been destroyed, or the thermofuse is defective, which is generally the case because of the mounting location. Click here for more info.
DMR702 Thermalfuse Fault Code 2 . Please see the above error code, this is the same error code. "Thermal Switch or Thermal Fuse" is the Dometic recall which generally trips for no good reason, the Fridge Defend by ARP will prevent this recall from tripping due to an overheat situation.
DMR702 Communications Fault Code . There is no communication between the control in the cooling unit compartment and the display on the front of the fridge. Check the wiring connections, power down the system and restart.

Also see following section on troubleshooting & click on this link for more Dometic troubleshooting information.


RM3762 Error Codes

ERROR CODE MEANING
EO There is not communications between the Dometic control board in the cooling unit compartment and the front display panel. Check for bad wiring connections, power down and back up.
E1 LP gas valve fault. Check the resistance of the valve solenoid. Check gas pressure, purge LP lines and restart.
E2 There is an error with the refrigerated space temperate sensor (thermistor). Check for bad connections, use the table below to check thermistor resistance.
E3 The 'thermo fuse' on the boiler housing is open. If the boiler housing thermal switch trips due to over heating, most likely the fridge has failed. Install the patented ARP Control to protect from fridge failure.
E4 Problem with fridge power supply, not in the range of 8 to 18 VDC. Use DMM and measure power and ground to fridge. Check voltage at 'terminal block' as seen in first image on this page. Be sure to check ground connections.

RM3762 Thermostat

MESSAGE MEANING
LP The LP gas operation is locked out. This usually occurs with the propane bottle is empty, or this can happen if the flame is blown out and the fridge fails to reignite the flame. Check to see if propane needs to be refilled, check gas pressure. Turn off the fridge and restart to see if error goes away.
60 The cabinet (fresh food compartment) temperature is above measurement range. The fridge will run constantly, and possibly freeze the food in the cabinet if the sensor has failed. Click here for Dometic troubleshooting information.

The RM3662 has a method to check the Dometic thermostat which regulates the fridge cabinet (fresh food compartment) temperature. Use the control panel 'TEMP. SET' button to read the cabinet temperature by pressing the button once to display the current thermostat setting 1-5, where 5 is the coldest. The 'TEMP. SET' button can be pressed again to change the thermostat setting, or if one changes the setting to '3', and then wait 5 seconds, the cabinet temperature is displayed. Use this setting and the Dometic Service Manual Repair Specification to check the thermistor.


Wiring ARP Control on 7 Cubic Foot Dometic Fridge

RM3762

Click here if your fridge has a boiler thermal switch that is wired in line with the power supply.

DMR702; DMC702

Late model Dometic where Boiler Housing Thermal Switch (thermofuse) is wired directly to the Dometic control.

ARP Fan Install

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

Please see the full ARP User Manual and Installation Guide for more information needed before using your ARPrv Control.


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: DMC702 DMR702 RM3762 RM3762RB RM3762RBIMF RM3762LSS Units
ARP Control Boiler Temperature 185-195 185-195 185-195 185-195 185-195 180-190 Celsius
Off-Level Operating Limit dependant on ambient temperature
Minimum DC Power Supply 9.5 9.5 9.6 9.6 9.6 9.6 VDC
Maximum DC Power Supply 15 15 22 22 22 22 VDC
Maximum AC on 12VDC Supply Line 6 6 6 6 6 6 VAC

Fuses

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

AC Power

Operating Range 108-132 108-132 100-132 100-132 100-132 100-132 VAC

DC Heaters

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

AC Heaters

AC Heater Power Rating 325 325 295 325 325 325 Watts
Current 2.7 2.7 2.5 2.7 2.7 2.7 Amps
Heater Resistance per Heater (cold) 44 44 48 44 44 44 Ohms

LP Gas

Gas Pressure 10.5-11.5 10.5-11.5 10.5-11.5 10.5-11.5 10.5-11.5 10.5-11.5 inch w.c.
Gas Jet #57 #57 #53 #58 #58 #58
Gas Thermocouple 25-35 25-35 25-35 25-35 25-35 -- mili-Volts
Electrode to Burner Gap 3/16 3/16 3/16 3/16 3/16 3/16 inch

Fridge Temperature Sensor

Thermistor @ 33degF to 35degF 7k-10k 7k-10k 7k-10k 8k-10k 7k-10k 8k-10k Ohms
Please click here for more information on Dometic thermistor troubleshooting.
Also see this post on the thermal fuse issues associated with this fridge.

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