twin fans mounted behind the fridge

Sorry I should have indicated that the two door side by side was a Dometic NDR 1292.The coach is a 2004 Fleetwood Pace Arrow model 37C. I did notice two fuse holders with glass fuses in them so I will check them out and see if the said fans will operate. Thank you all for your responses! Safe roads!

Here are the images.

Sure Sam

1. The attic fan thermostat replaced a non-working fixed temp thermistor. This allowed to adjust the fan on, set point so the fans come on sooner & run longer, improving heat transfer.
2. The Twister fans replaced a pair of OEM sleeve bearing fans. One OEM had seized & the other was getting louder. The Twisters have magnetic bearings so the fan floats on a magnetic field. This reduced noise, current draw, & increased reliability I hope. (3 years and still church mouse quiet)
3. The ISO board (R-Max 1/2") was added mainly to block solar gain. I did this to both keep more of the cold in the freezer & upper chill box & as a buffer to the slide wall heat gain when the sun is beating on that side of the trailer. The amount of improvement was not discreetly monitored, I believed it did help a bit.
4. The internal chill box thermistor mod of adding resistance in parallel initially consisted of a 100K? pot. I have since added a 33K? fixed resistor in series with the pot to get the full range use of it and added a switch to return to stock if the pot fails or to test. (The original Radio Shack pot failed after 2 years) This mod makes the controller believe the chill box is warmer than reality, causing it to keep the heater on longer thus driving down the inside temp 2-8°F.

Previous to the mods our unit had difficulty when temps were above 90°F, a 5 setting was not keeping it out of the 46-54°F range. now the unit hovers in the low-mid 30's on 2 or 3 depending on outside conditions. (Hi 90 - 100's I set it on 3) The efficiency is greatly improved IMHO, YMMV.

One side effect is the Digital readout on the fridge is now erroneous, now reads 38-40 vs 33-35 & not linear in its error. We use an inside/outside remote thermometer to keep track of actual temps.

When the pot failed (went from 100K? > 5K?) the symptom was a freezing chill box as the heater never shut off. Switching the mod off is safer than turning off the fridge @ night.

We have setup in a mid Texas church tarmac lot this summer for 3 weeks @ 90 - 103° temps and not a problem.

Pics to follow.

SCClockDr wrote:
Hi All

I made a few mods to our Refer to improve its cooling function.

• Replaced failed external fan thermistor with an attic fan thermostat from Lowes
• Replaced the OEM external fans with Magma 12CM Fan Magma Component Twister Bearing Detach Blade
• Added R-Max Iso board insulation to the rear of the refer and the inside of the slide wall.
• Installed a 100K pot from Radio Shack in series with the chill box internal thermistor to fool the control board's temp sensing

A couple of sample images.

Looks great. But could you tell us how this improved the efficiency?

Thanks,Sam

Hi All

I made a few mods to our Refer to improve its cooling function.

• Replaced failed external fan thermistor with an attic fan thermostat from Lowes
• Replaced the OEM external fans with Magma 12CM Fan Magma Component Twister Bearing Detach Blade
• Added R-Max Iso board insulation to the rear of the refer and the inside of the slide wall.
• Installed a 100K pot from Radio Shack in series with the chill box internal thermistor to fool the control board's temp sensing

A couple of sample images.

Old-Biscuit wrote:
If fridge is installed in a slide out it should have (needs) external fans to move more air across coils due to lack of natural draft. They are normally wired from fridge 12V system and have a t-stat that controls ON/OFF....IIRC they turn on at 85*F

The tstat is at 130 degrees to turn ON. Doug

You do not say what kind of unit you have but if it is the 4 door unit I believe they all come standard with the double fans. As Old-Biscuit said these are thermostatic controlled. Check fuses first, then make sure you have proper connection, then check the thermostat that controls the fans. I believe in most cases you will find that thermostat is at the top of the coils. I am sure if you get your model number and serial number, go on the internet and you can download a detailed manual for the unit, at least if it is a Norcol. That is what I did and it gives a good trouble shooting guide, etc. A very valuable addition to my manuals.

If fridge is installed in a slide out it should have (needs) external fans to move more air across coils due to lack of natural draft. They are normally wired from fridge 12V system and have a t-stat that controls ON/OFF....IIRC they turn on at 85*F

.

1. State the Year/Brand/Model number of the refer
2. I will guess a Norcold 1200 series or a Dometic NDR series
3. If Norcold and your refer is in a slide, then those fans are critical for the refer to operate. If Norcold, NO FUSE for the fans if the inside controls function. There is a Tstat on the rear upper condenser fins that controls the Fans. Jump those 2 wires and the fans should come on. If NOT, the odds are the fans are defective.
4. If Dometic the fuse will be at the rear bottom by the electrical connections to the refer. Dometic has the same tstat on the upper fins that control the fans also
5. IF the refer shuts down, then the odds are you have a Norcold, as Dometic's will not shut down from lack of ventilation
6. Are you getting a NO CO code? Doug