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rkoepsell · 08-28-2013, 09:52 AM

I have a 2011 23D trailer and, when I turn on the refrigerator, the external heat exhaust fan runs almost continuously, even when the outside temperature isn't particularly warm. Is there some sort of thermostat/thermocouple that can be adjusted or checked? Thanks

dznf0g · 08-28-2013, 09:58 AM

I believe they use a thermal switch in the chimney area. That's what I did for a mod (mine had no factory fan) I used a 140* switch, so it is on all the time except in cool/cold weather, when the burner/element is off long enough for the switch to open.

I don't know what AS uses for a switch temp, but I suppose you could move it higher or lower on the chimney to balance on/off time weighed against refer cooling efficiency, of course.

overlander63 · 08-28-2013, 10:58 AM

The switch is not on the chimney, but on the coils of the cooling unit itself.
If you really wanted to, a combination of an on-off switch and a good, quiet computer fan will help the noise level a lot.

dznf0g · 08-28-2013, 11:03 AM

I did install an on/of switch as well. I have found the fan reall isn't necessary unless ambient temp is above 80 - 85*F. Terry, could moving it around on the coils then produce different on/off times?

DoggerStream · 03-26-2014, 09:02 PM

Hi:

We were told by our Airstream dealer than this fan (I believe he called it the reefer fan) has to be on everytime the refrigerator is on. Last weekend, we were in Joshua Tree Ntl Park and it averaged about 75 degrees. The fan ran the entire 2 1/2 days and only shut off in the middle of the night when it got really chilly. Where would I install the on/off switch? Wouldn't this be redundant since there is already a switch on the inside of the trailer? Also, it seemed that like our batteries died a lot quicker on this trip than other trips where the fan didn't run as much. We have a 19 foot Bambi CCD International.

Thank you,
Laurie

subfan1 · 03-26-2014, 09:17 PM

Laurie, yes you can turn the fan off with the switch inside your trailer. We turn ours off at night and open the top door while we are at our campsite for additional cooling. I'm going to add ducting from the boiler out to the door. Someone here has done it with good results. Reducing the heat in the compartment thus reducing the amount of time fan stays running.

idroba · 03-26-2014, 11:24 PM

See this thread on the subject. It is long and involved.

http://www.airforums.com/forums/f425...lly-11811.html

You will find my post #96 on ducting of the boiler heat out to reduce the heat in the compartment that the fan has to deal with. Some other posts after that # have questions and my answers.

subfan1 · 03-27-2014, 05:43 PM

I went ahead and bought the elbows and installed them similar to what you did idroba I'll have to wait until the next trip to see what kind of difference this makes. What is the center thing that moves around that comes out of the center of the boiler? I had to move it around to get the elbow inserted flush to the top of tube.
Thanks for the tip

idroba · 03-27-2014, 06:58 PM

The center thing is a flue baffle which is a screw shaped piece of metal which twists the heat and exhaust gasses so they touch the side of the boiler tube and transfer heat better. I also had to fiddle around with it a bit so it would not interfere with the added ductwork.

I hope you like the modification, it took a big portion of the heat load from my upper cabinet when operating on propane. Then the quieter fan does the rest.

perryg114 · 03-28-2014, 06:23 AM

On the older fridges there was no fan. Why do the new fridges require a fan when the old ones did not?

Perry

subfan1 · 03-28-2014, 06:28 AM

I'm thinking because the older units are vented to the top?

perryg114 · 03-28-2014, 06:34 AM

They all are because of the flu for the propane fumes.

Perry

subfan1 · 03-28-2014, 08:02 AM

The trailers with the two vented doors on the side are not vented to the roof therefore the need for a fan. These are the smaller 8 foot wide newer models.

idroba · 03-28-2014, 08:34 AM

Airstream has used several venting systems over the years. The first and best one was when the air came in through a screened opening in the belly pan and up through an opening in the sub floor, and out through a vent in the roof. Access to the refrigerator back was through a door in the outside of the trailer. Gravity did all the work to remove the refrigerator heat and it was an excellent system.

The next variation eliminated the hole in the belly pan and sub floor, and brought the cooling air through the access door to the back of the refrigerator by cutting vent holes in the door and screening it. Air still went out the roof vent. It worked pretty well.

The latest twist is to put two outside access doors on the refrigerator compartment, both with holes, to eliminate the roof vent. The air chimney is only about 3' high max and so does not work nearly as well as an 8' high stack of the old system. So, to augment the air flow, they put a fan at the top access door to move air through the system.

The problem is that the fan they use is loud and takes power all the time to run it. For us boondockers the noise is unwelcome in quiet locations and the constant battery use is not good.

The partial solution has been to replace the original fan with ones which make less noise and use less power. I have gone one step farther by directly venting the boiler heat and propane gasses from the top of the refrigerator directly to the outside so they don't add to the heat which must be eliminated by the fan in the compartment.

BTW, the earliest Airstreams with propane refrigerators used a 2" vent pipe for the propane heat and gasses from the boiler and that pipe went up through the roof like a plumbing vent. The refrigerator coil heat went directly into the rig, via a screened vent in the countertop. I had a 1960 which was set up that way from the factory.

Ask a question, get a pageant! Grin.

idroba · 04-22-2014, 10:29 AM

Quote:

Originally Posted by idroba

The partial solution has been to replace the original fan with ones which make less noise and use less power. I have gone one step farther by directly venting the boiler heat and propane gasses from the top of the refrigerator directly to the outside so they don't add to the heat which must be eliminated by the fan in the compartment.

I want to post that in getting the FC out this week I noted a discolored spot on the upper refrigerator vent cover. It turns out that my direct venting of the boiler heat to the outside vent was/is hot enough to damage the clear coat on the vent cover.

So, anyone following in my footsteps needs to be aware of that possible disadvantage. I don't intend to change my system but I sure don't want anyone else to do it not understanding what I have just now found.

I made another post on the subject, with a photo and am trying to find that post so I can make a similar statement there.

KWC · 08-27-2014, 04:06 PM

Yesterday we had to take our airstream to have the AC repalced and turned off the fridge for the 2 hr journey and while in the shop. . The cooling fan stayed on and was still running when we left the unit. Should the fan be on even when the fridge is off (gas also) ?

idroba · 08-27-2014, 04:27 PM

No, the fan is thermostatically controlled with a Klixon switch on one of the cooling fins. I don't know what temperature at which it operates, but it should be high enough so it is never on when the refrigerator is not running. I think you have a defective thermostat in the fan circuit.

KWC · 08-27-2014, 05:10 PM

Thanks . We have a 2012 23fb international Serenity which is new to us. Any idea where the thermostat is located? Had a quick look in the out side upper compartment and recognized only the fan ? We are in S Fl and the temps are in the 90's and high 70's at night.

murreywalker · 08-27-2014, 05:34 PM

There are two solutions (IMHO) to the "cooling" fan in the 23 as far as I'm concerned.

1. When camping and the noise is bothersome, go out and remove one of the bayonet clips that supply 12v.

2. Install a cutoff switch in the closet next to the microwave and tie it in to the fan which is behind the microwave.

idroba · 08-27-2014, 06:31 PM

Quote:

Originally Posted by KWC

Thanks . We have a 2012 23fb international Serenity which is new to us. Any idea where the thermostat is located? Had a quick look in the out side upper compartment and recognized only the fan ? We are in S Fl and the temps are in the 90's and high 70's at night.

On my 2014 FC 20, when you lift the upper vent you can see the fan and the wires which go to it. One of them goes to a little round device with ears on it. That is screwed to one of the fins on the upper right side of the uppermost coils on the unit. On mine, that is the thermostat. Mine also has a switch with light on it inside, so the fan can be turned on and off manually, assuming the thermostat says it is warm enough.

Now, your 23 may be different, and I understand that not all rigs with a fan had a switch inside to turn it on and off.