Now being the new owner of a 2601TFB, I can' find any information on "why" or "when" to switch this exhaust fan on? My old 2176B had no such fan and I'm not sure what the purpose is.

Would it be to help exhaust any fumes using the propane for the Refer while traveling?

Hi Bruce - The exhaust fan is not there to get rid of fumes. It draws air over the heat exchanger fins behind the refrigerator which helps to cool them down. Essentially, the heat removed from the inside of the refrigerator is transferred to these fins by the action of the ammonia coolant. As the fins heat up, they lose the ability to accept additional heat from the space you want to keep cold. So, moving air across them gets rid of some of that excess heat to improve your cooling efficiency.

If you go outside and if the refrigerator fan is actually running, you can feel this air flow and heat at the vent behind the refrigerator. I say "actually running", because the fan does not start turning until the temperature at that heat exchanger reaches some threshold level (I think it's 120 degrees, but I could be wrong). So, just flipping the switch does not actually start the fan, it just "arms" it so it will run when things heat up.

Some people don't bother to turn the fan on if it's cold out. Personally, I turn it on any time the refrigerator is on. AND, if you are traveling with the refrigerator on and the top is down, the fan SHOULD be on because the air circulation behind the refrigerator is restricted.

- Jack

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Hi-Lo 1707T - Tire Minder TPMS on Tow Vehicle and Trailer, 300W Solar Battery Charger, Equal-i-zer WDH, Progressive Dynamics Converter, Fan-Tastic Fan, LiFePO4 battery 12V DC Electrical System, SoftStartRV mounted on A/C
2024 F150 Platinum FX4 3.5L PowerBoost SCrew

Thanks Jack! I wasn't aware that it is automatic. Than makes much more sense now. With my old 2176B while traveling, I always had the roof vent cracked open a bit, and had the rear window open a bit too (that didn't work too well on dusty roads!).

Bruce, I replaced my noisy, high amperage, OEM fan with a couple PC fans. The thread where I discuss this is here: http://www.hilotrailerforum.com/f35/...rator-fan-261/ My installation narrative, with pictures, starts in post #11.

The original fan was loud enough to wake me at night, and it used more battery power than the two new fans. We like to boondock camp, so saving power is a big deal for us.

- Jack

Should the fan be blowing onto the fins or exhausting warm air out?

Quite an informative Thread! Thanks for the tips. Still have to get a 110 Amp to 30 Amp adapter to even know if the previous owner made any changes. Although, it probably wouldn't bother me to much anyhow, except the Battery use.

Hi Tom. The original fan had the air being drawn in from the lower openings at the side of the trailer, up through the fins of the heat exchanger (radiator) and out through the fan and the upper openings. So, the fan "pulled" air across the fins, rather than "blowing" air onto them.

Using the principle that warm air rises, I simply duplicated that direction of air flow, since trying to reverse it seemed to me to be less effective.

However, I built the shroud so that the fans would concentrate the air movement THROUGH the fins rather than pulling some of the air from other places.

- Jack

Thanks Jack. I don't remember which way the factory fan is blowing but it's mounted in the upper vent. I did at one time re mount it to lower the noise but didn't help much. I added a small 110v fan in the lower vent area tilted s bit up blowing in and up and it is almost silent. I just leave it plugged in where the fridge plugs in and let it run all the time when hooked to shore power. I switch the factory fan on but it never needs to run when the 110v fan is running.

Sounds right, Tom. I think having a fan in the lower section would certainly keep the fins cool. I thought it would be easier to replace the one in the top, since I didn't like it anyway, so that's the route I took.

- Jack

I'll get a picture of it this weekend. Going on a first of the season shake down trip.

I will need to run my fridge with the top down. Is the fan enough? I almost think I need to do a mod and put in an exhaust or fan to move the gases out when it is closed. I think when the top is closed that the seal is broken and gases could vent into the cabin. ???

I think I'm pretty typical when it comes to running the fridge down the road. I start about 24 hrs earlier, with the trailer on shore power. I turn the fridge on in the ac mode, a few hours later, when well cooled, I stock it with my cold stuff from the house. Just prior to leaving, I switch to dc mode thus running off the TV. (I have up-graded my TV wiring with heavier gauge wire for more amps to the Hi Lo). We usually drive from four to six hours on the road, then set up camp. Have never lost ANY food. I have forgotten to switch to 12v on two occasions, run about four hours on the road and the refer is STILL very cold. Because of safety (in my mind), I have never driven with the refer on gas.
As for fan noise, check out the "sushi mod".
Tree

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2703 Tow Lite
2002 Escalade
Bonita Springs, Fl. &
Andrews, NC

Although the Switch has been "on" ever since I obtained it, I've yet to "hear" the exhaust work on my 2000? Don't know that it even works, and am Not too worried about it because the Refer almost works too well!

Have to keep it set low, especially on Gas, because it tends to freeze some liquids, etc.

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Formerly 2176B Classic since 1988, needs work!
Now 2600TFB since May 2017
1982 G20 3/4 Ton Chevy Sportvan
Navy Vietnam Vet