Chris, I have been following your post.
I did review the ARP system a while back, just never made it to installing any, yet. I called and talked with them today. They are very down to earth, and they are a, know what they are doing company.
I am going with the Fridge Defend V5.11 with the fan control. I want to add the defrost fans inside the fridge and to cycle them you need the fan control version. The V5.11 has an alarm, so you know when you have a problem and you and tweak the settings as needed. Since most all the fridges I work on are older, there may be some level of coolant damage from prior owners, so the fridge may have limited life, but having the fire safety part is a big plus.
Since I already have a fan up on the roof vent and a thermal disk switch to turn it on and off, I may switch the roof vent fan to the Fridge Defend. You just parallel the inside defrost fans with the roof vent fans. The ARP fan relay is rated at 20 amps, plenty for the milli amp fans I use, and the ARP defrost fans.
Another reason for the Fridge Defend not yet mentioned is cold weather. I know you may not camp in cold down to freezing, and below, but in our area, freezing temps are here and we do winter camp.
If you want to get close to 32F outside or go below, the fridge as it stands in the stock configuration will slow down and may stop working. The heating may not stop, but the fluid can slow down flowing from what I have read. It seems Dometic does offer a lower vent hood that has some blocked off vents to lower the amount of cold air entering.
This Dometic lower vent is made for cold weather, just they do not list much else or fit the older Dometic vent frames. Norcold sells a cold weather kit to heat up a certain return tube on the cooling coil. Here is one of them.
https://www.amazon.com/Norcold-634913-Cold-Weather-Kit/dp/B00T36VI30I have not been able to find Dometic offering that heat strip. By using the heat strip on the Norcold and helping to reduce the cold air intake, it is reported you can go down to 0F. Some folks use an incandescent light bulb in the outside compartment.
The ARP system will help to shut off the boiler heat if the coolant stops flowing due to the cold weather for any reason.
Doug may be able to add some more to this and if he knows if Dometic offers a cold weather kit or do you just use the Norcold one? Most all of the older campers I restore have RM2652 fridges that I service.
Thanks
John
