DM2852 • DM2862 • DM2872 • RM2807 • RM2811 • RM2812 • RM2820 • RM2852 • DM3862 • RM3862 • RM3962 • RM3972 • RM4804 • RM4872 • RM4873

The Fridge Defend by ARP improves safety, efficiency, and reliability, can you live without it? This page show the install for the vast number of models Dometic makes for 8 & 9 cubic foot volume.


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 RM3862

Dometic 8 & 9 Cubic Foot Cooling Units

The Dometic 8 and 9 cubic foot fridges are found in both Class-A and Class-C motorhomes. In addition these excellent fridges are also found in many Fifth Wheel RVs.

The Dometic cooling unit design is very efficient when compared to other cooling units, but there is a trade-off for efficiency, these cooling unit are vulnerable to boiler overheating that can result in a damaged refrigerator, or even worse, a fire. Click here to see how the ARP helps prevent these problems.

This photo shows a typical Fridge Defend installation within the cooling unit compartment. The Fridge Defend is mounted directly to the Dometic control box. Please see below for wiring diagrams by refrigerator model.


Airstream RM2862

Airstream RM2862

This photo is a Dometic RM2862 with the Amish cooling unit installed in an a Airstream trailer. The owner of this fridge led Airstream caravans. This gentleman went through a number of refrigerators, both new and rebuilt. When he found out about the Fridge Defend by ARP he was intrigued to say the least.

One issue with the Airstream trailer is the distance the fridge is mounted from the vent. We highly recommend the Fridge Defend + Fan Control for this application.

Please click here for more information on the Fridge Defend + Fan Control.

RM3862 Amish Cooling Unit

Install Boiler Sensor

This photo is a Dometic RM3962 boiler, all of the 8 and 9 cubic foot fridges have similar boilers. The two green arrows show a crimp that is put into the boiler tube to hold the inner percolator tube in place. Do not place the tip of the ARP temperature sensor (blue arrow) so it straddles the gap resulting from these crimps.

Please be careful to position the ARP temperature probe away from the flue tube (red arrow). In addition, fill the area around the temperature sensor with insulation so that the area between the black arrow and the flue tube is packed. If there is a gap between the temperature sensor and the flue tube, the heat from the flue tube will give the temperature senor a false reading thereby preventing the control from functioning properly, thus fill all gaps with insulation.

Click here for temperature sensor install video.

Dometic RM3862 Cooling Unit

This photo is of a Dometic RM3663, it is similar to the above photo, but it shows more detail of the cooling unit compartment.

Please note the heavy power wires on the right side of this photo. Please be sure to always insulate these wiring harnesses that run through the cooling unit compartments. The heat from the cooling unit can melt the insulation on the wires, thereby causing an electrical fire. Yes, not all fires that originate in the cooling unit compartment are due to the boiler of your fridge overheating!


Wiring ARP Control on 8 and 9 Cubic Foot Dometic Fridge

RM2807; RM2811; RM2812; RM4804; RM4872 (Early 2-Way)

Please click here for the details of wiring the 2-way models without the boiler thermal switch recall.

RM2852; DM2852; RM2862; DM2862; RM3862; RM3962 (Late 2-Way with Recall)

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

RM2807; RM2811; RM4804 (Early 3-Way Modles)

For the early 3-way models where all of the current is routed through the power supply to the fridge control. The ARP can not power the 3-way heater and a relay is required.

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: RM2807 RM2811 RM2812 RM2852 DM2852 RM2862 DM2862 RM4804 RM4872 RM4873 RM3962 Units
ARP Control Boiler Temperature 185-195 185-195 185-195 180-190 180-190 180-190 180-190 180-190 185-195 185-195 185-195 Celsius
Off-Level Operating Limit 0
Minimum DC Power Supply 9.6 9.6 9.6 9.6 9.6 9.6 9.6 9.6 9.6 9.6 8 VDC
Maximum DC Power Supply 22 22 22 22 22 22 22 22 22 22 18 VDC
Maximum AC on 12VDC Supply Line 6 6 6 6 6 6 6 6 6 6 6 VAC

Fuses

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

AC Power

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

DC Heaters

DC Heater Power Rating 215 215 -- -- -- -- -- 215 -- 215 -- Watts
Current 17.9 17.9 -- -- -- -- -- 17.9 -- 17.9 -- Amps
Heater Resistance per Heater (cold) 0.67 0.67 -- -- -- -- -- 0.67 -- 0.67 -- Ohms
Fuse 30 30 -- -- -- -- -- 30 -- 30 -- Amps

AC Heaters

AC Heater Power Rating 325 325 325 325 325 325 325 325 325 325 325 Watts
Current 2.7 2.7 2.7 2.7 2.7 2.7 2.7 2.7 2.7 2.7 2.7 Amps
Heater Resistance per Heater (cold) 44 44 44 44 44 44 44 44 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 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 #58 #58 #58 #58 #58 #58 #58 #58 #58 #58 #58
Gas Thermocouple 25-35 25-35 25-35 25-35 -- 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 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 8k-10k 8k-10k 8k-10k 8k-10k 7k-10k 7k-10k 7k-10k Ohms
Please click here for more information on Dometic thermistor troubleshooting.

If you can not find what you need please use the Contact Us form from the top or bottom menus.