Enhanced Cooling Efficiency: RV Interior Refrigerator Fan Installation Review

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M_MINCEY
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Enhanced Cooling Efficiency: RV Interior Refrigerator Fan Installation Review

Post by M_MINCEY »

I recently embarked on another mission to enhance the performance of my Dometic RM3663 3-Way refrigerator by installing internal fans. After conducting thorough research I stumbling upon recommendations from fellow RVers, I decided to give it a shot and purchased a couple of internal fans to see if they would improve the cooling efficiency of my fridge. Today, I completed the installation and eagerly await tomorrow's test to gauge the impact.

The installation process itself was fairly straightforward, thanks to the accompanying images and instructions provided by the manufacturer. The fans were designed specifically for absorption refrigerators, and their compact size fit perfectly within the unit. The materials used felt durable, ensuring they would withstand the demands of the RV lifestyle.

The true test, however, lies in the performance. The internal fans are intended to circulate air within the refrigerator, aiding in temperature regulation and ensuring a more even distribution of cold air. If my initial observations are any indication, these fans should make a noticeable difference. In terms of potential future modifications, I am contemplating installing an external fan at the back of the refrigerator. This addition could potentially provide an extra boost to the cooling process and further enhance the overall performance.

https://www.chinookrvforum.com/viewtopi ... 529#p21529

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2002 Chinook Destiny 2400 XL Class B w/Chevy 8.1 Vortec Engine.
M_MINCEY
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Re: Enhanced Cooling Efficiency: RV Interior Refrigerator Fan Installation Review

Post by M_MINCEY »

Here are some additional images of the installation that was completed.

Regards!

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2002 Chinook Destiny 2400 XL Class B w/Chevy 8.1 Vortec Engine.
deppstein
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Re: Enhanced Cooling Efficiency: RV Interior Refrigerator Fan Installation Review

Post by deppstein »

When I had my frig rebuilt by JC Refrigeration (the Amish Frig Guys), they installed a dual internal fan similar to yours, as well as an external fan with a thermo setting of 130 degrees to help keep the outside back of the frig cooler. Both work great. My frig runs one setting cooler than it used to and their electrical draw is not significant.
David
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Re: Enhanced Cooling Efficiency: RV Interior Refrigerator Fan Installation Review

Post by M_MINCEY »

Hello David, I greatly appreciate the information you provided. Prior to your suggestion, I was unfamiliar with JC Refrigeration. The reason I opted for these fans was due to their low amperage per fan (0.2A) and their quiet operation as brushless fans. Considering I have a total of four fans, with a combined current of 0.8 amps and a voltage of 12 volts, the overall power consumption amounts to 9.6 watts. This level of power consumption should not have any adverse effects on the MICRO P-711 board, especially considering it is equipped with a DC 5 amp fuse. Furthermore, I've been exploring the idea of replacing the incandescent bulb with an LED alternative, as this switch is likely to reduce the overall amperage usage. In terms of the installation of external fans, one of my concerns is ensuring the protection of the 12-volt circuit while also taking advantage of the 5 amp fuse on the P-711. I am considering piggybacking out of J2 on the board. I would greatly appreciate your thoughts and insight.

Best regards!
2002 Chinook Destiny 2400 XL Class B w/Chevy 8.1 Vortec Engine.
deppstein
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Re: Enhanced Cooling Efficiency: RV Interior Refrigerator Fan Installation Review

Post by deppstein »

M_Mincey—I don’t think I’m in a position to give you any advice…you are ahead of me! What you researched and did on your own, I had done as part of a complete rebuild of my 3-way (now a 2-way) Frig. The primary impetus for having the Frig refurbished was to replace the 17 year old tubing and “guts” to hedge my bets against having a refrigerant leak and fire—heard story here on forum and elsewhere of rusted equipment causing fires and didn’t want to take any chances of that happening to me since I run Frig on propane almost all the time. That’s how I found the JC Refrigeration folks who specialize on rebuilding “in place.” Not having to pop a window or whatever to get old Frig out and new one in. Others have gone to compressor Frig, but my use parameters and lack of battery power (I’m still using two group 31 wet cell deep cycle batteries) make that a less attractive option for me. The addition of the internal and external fan for improved efficiency was a bonus and secondary to my fire concern. All that to say that I didn’t really pay attention to how they wired the fans/where they tied into the Board, etc. I’m just not very good at that stuff.
Only real electrical mod I have made myself was to upgrade the original charger/converter to a “smart” Progressive Dynamics 4645 to improve battery charging. I also had someone do the wiring to tie my Zamp Solar Suitcase panels to my batteries, and replace the original Shurepower unit that connects alternator to house batteries with a Blue Sea unit as recommended by other (more knowledgeable) Forum members.
But, I’ll bet if you give the folks at JC Refrigeration a call and talk to them about where to wire an external fan, they will be will be willing to help you out. They are really nice people (you could even buy the fan from them).
Best,
David
chin_k
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Re: Enhanced Cooling Efficiency: RV Interior Refrigerator Fan Installation Review

Post by chin_k »

I wonder if it is worthwhile to have a thermostat for these recirculation fans? This way, it only draw the 9.6 watt when the air needs to recirculate, instead of running all the time? When the air is cold enough, it will only draw the power for the thermostat, which can be much less than one watt even if you use electronic thermostat. (mechanical thermostat use no electricity, but may not be precise enough).
2000 Concourse dinette, on 1999 6.8L Ford E350 Triton V-10 Chassis
deppstein
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Re: Enhanced Cooling Efficiency: RV Interior Refrigerator Fan Installation Review

Post by deppstein »

If I am boondocking for an extended period of time, I sometimes use an internal, battery operated, cubed interior Frig fan to save on electrical use. Works well when I need it.
David
M_MINCEY
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Re: Enhanced Cooling Efficiency: RV Interior Refrigerator Fan Installation Review

Post by M_MINCEY »

Once again David thank you for the reply, I recently had the opportunity to contact JC Refrigeration regarding my RV refrigerator's cooling issues, and I must say, their service was impressive. From the moment I reached out to them, they were incredibly helpful and knowledgeable.

During my conversation with one of their technicians, I inquired about the installation of external ventilation fans for my refrigerator. The technician informed me that they could connect the fans directly to the 12 Volts from the battery, providing an effective cooling solution. However, I expressed my concern about the lack of an in-line fuse to protect the circuit and the fans in case of any malfunctions. Surprisingly, the technician agreed with my observation and suggested an alternative approach.

Upon contacting Dinosaur Electronics for further clarification, I received confirmation that my proposed idea of utilizing the 12 volts power from the Dinosaur MICRO P-711 Dometic Refrigerator Board (J2) was indeed feasible. This consensus between JC Refrigeration and Dinosaur Electronics instilled confidence in me regarding the solution I had in mind.

To put the theory to the test, I decided to assess the effectiveness of the internal fans I installed in refrigerator. These fans are designed to circulate air within the refrigerator, contributing to temperature regulation and ensuring a more uniform distribution of cold air. At 12:00 PM, I switched on the refrigerator using propane, and at that time, the internal temperatures stood at 77 degrees Fahrenheit.

After two hours of operation at a setting of 4, I measured the temperatures in the freezer and refrigerator compartments. The freezer reached around 47 degrees, while the refrigerator showed a temperature of approximately 61 degrees. Admittedly, I did not capture the readings with my Remote Digital Wireless Fridge and Freezer Thermometer, as I was already contemplating the addition of external fans.

Curious to see if the installation of external fans would yield any improvements, I connected an oscillating fan to the back of the fridge and rechecked the temperatures at 7:00 PM. To my amazement, the freezer temperature dropped from 47 to 8 degrees, and the refrigerator temperature decreased from 61 to 48 degrees (images available below). Although this experiment lasted only 5 to 7 hours instead of a full day, the results indicated that my refrigeration goals could be met with the help of external fans.

Based on this small test, it is clear that both internal and external fans contribute significantly to maximizing the efficiency of my over 20-year-old refrigerator. Therefore, I have decided to proceed with purchasing the external fans this week. I intend to provide an update after their installation to share the overall impact on the refrigerator's performance.

In conclusion, my experience with JC Refrigeration and Dinosaur Electronics has been positive thus far. Their responsiveness, expertise, and willingness to explore alternative solutions have instilled confidence in me as I seek to improve my RV refrigerator's cooling capabilities. I look forward to the installation of the external fans and the subsequent positive impact on my refrigeration system.

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2002 Chinook Destiny 2400 XL Class B w/Chevy 8.1 Vortec Engine.
deppstein
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Re: Enhanced Cooling Efficiency: RV Interior Refrigerator Fan Installation Review

Post by deppstein »

M_Mincey…glad to hear of your positive interaction with the JC Refrigeration folks—and that you got the confirmation you were seeking from them and the Dinosaur Board techs. And thanks for taking the time to report on the results of your Frig cooling experiment. Good to know!
Chin_k…fyi, the external fan that the JC Refrigeration folks installed on the back of the Frig is tied to a 130 degree thermostat, so it only runs “as needed.”
David
BobW9
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Re: Enhanced Cooling Efficiency: RV Interior Refrigerator Fan Installation Review

Post by BobW9 »

M_Mincey, to be a viable test you need to let the temperature of the fridge and freezer stabilize before adding the fans. These 2-way and 3-way fridges take many hours to get to their normal operating temps - much more than 2 hours. I'm not even sure you reached normal temps for your fridge by 7pm, certainly the fridge at 48 degrees makes me think not (unless you're having an issue with the normal operation).

When I start up my fridge after the RV's been in storage, I always turn it on the night before. Then when I'm ready to start packing and loading the fridge in the morning, it's been at least 12 hours.

I do use internal fans in the fridge, but it is a difference of only maybe 3-5 degrees at most. The best thing the fans do is to circulate the air and keep the temperature more even over all the food, especially when the fridge is full. I find it also helps a bit with the metal fins icing over less. I have never found the freezer to need a fan - it is small enough, and always operates more efficiently than the fridge section, anyway. I also have never really found the need for external fans, though I do tend to avoid areas that are above 90 and humid.
2000 Concourse, Ford Triton 6.8 V10
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