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Open discussion on improving the Dometic refrigerator performance.


HOW-TO

"Improve Refrigerator
Hot Weather Performance"



A Dometic tech said I need an exhaust fan for my refrigerator to improve its cooling in hot weather.

There are 2 ways I can go.

1. An exhaust fan installed in the section accessed through the fridge access panel. Bob Hunt has used this set-up (see pictures in my thread Casitas in hot weather) and is pleased with the results. I can buy the exact fan as Bob's at Camping World tomorrow.

2. Install a fan, that the Dometic tech left with me, in the upper exhaust panel. The downside to this plan is that I would have to drill out the rivets on this panel to install the fan. I would then have to reinstall the panel. The upside is that I already have the fan. However, since a new fan is only $25 and Camping World is less than an hour away, money is not a major factor.

I would like to hear back on 2 issues. Would it be better to have a fan below blowing toward the coils even though there are obstacles between the fan and the coils? Or, would it be better to mount a fan in the upper portion which would pull air out of the compartment and therefore draw air from the bottom?

Also, how difficult is it to remove the vent panel and reinstall it?

Either way, I am going to do what Bob did and not use a thermostat. Instead, I will install an on/off switch and that way I will have full control over the fan.

I need to do this soon so that I can test the fan to see if poor exhaust is the reason the fridge will not cool in hot weather.

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REPLY(S)

Bill,

I've been watching your situation with interest. I found a website with what I think is good info. I'll post it below.

Also, in my business networking group there is an appliance repair guy. I asked him what I could do to increase the efficiency of my Casita refrigerator. He said add a fan to the top and exhaust the hot air. Next best thing is to add a fan to the bottom and push hot air up. Getting the hot air out is the key. Notice that web site below is concerned with baffels. I think my Casita only has the upper baffel. I may do a little modifying to try and improve the efficiency.

Michael (113* today)

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If air flow is the problem, then how come mine always cools and freezes without a problem??? It must be the same set-up. I would think something else must be amiss or we would all be needing fans installed. Just a thought. James. Regardless, I do hope that resolves your problems. I hope mine keeps working, headed for Big Bend for about a week.

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Thanks for the quick replies.

I looked at the website and it said the preferred location for a fan was at the top.

James, your point about other Casita refrigerators is well taken. My original post last month received replies like yours saying that refrigerators in Casitas were doing fine in hot weather. I want to eliminate venting as a possible problem before going back to Dometic. Funny you should mention Big Bend. It was a trip to Big Bend last year when my fridge worked very poorly. It was late June and very hot. However, when I camped up in the Basin the overnight lows were below 60 and my fridge still never got cold. When I returned I had a Dometic tech look at it. He said nothing was wrong. Then Dometic did not want to pay for the call as a warranty call since no problem was identified. I had to call a Dometic service manager to get authorization for the service call. It was not a pleasant scene. Oddly enough, the fridge worked better the next time out.

Enjoy Big Bend. It is a great place. A Casita is a great trailer to take up to the Basin. Big rigs can't go up there due to the hair-pin turns at the top and the small campsites. There is no electric at the campsites. I don't remember if there is water. It is very scenic and the temps are not bad for Texas in the summer. We had to wear jackets at night. Be careful coming down. I lost my trailer brakes coming down. The added pressure on the truck caused its brakes to fail. By the time I got to the bottom I had no brakes. I was lucky that there was no traffic and that the hair-pin turns are at the top or I would have crashed. There is a long straight-away at the bottom that allowed me to slowly come to a stop. The brake pads on the truck were really smoking. I had to wait awhile for them to cool down. I don't know what happened to the trailer brakes. I unplugged the trailer from the truck and plugged it back in and they worked again. Maybe it never connected when I hooked up and I didn't notice. I was driving an F150 then. I now drive an F250 with the larger brakes and I always look at the brake controller light when hooking up. If you get a chance, go to the Davis Mountains. Another great spot.

I'll let you know how it works out.

Bill

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Venting is only a problem in extreme hot weather conditions. The Casita does not have the "best" venting. The Casita design (because of space) is pretty good. I had an expert certified Dometic repair person tell me that the Casita is Very well built.

You need a long vertical tube to get the best convection venting. On very hot days, a short vent does not draw very well. Thus, a fan helps expel the heat. Note the Casita is considered to have "Poor Venting". The other thing I noticed is that the Casita does not have the lower baffle. At least I could not see one on mine when I looked up there this afternoon.

I hope this helps.



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I just noticed that the Dometic tech left a DC24V 0.25A fan. Is there a problem with using a 24V fan on a 12V system? The fan is a Sanyo Denki model 109D1224H101. It is no longer listed on their website.

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After messing around all day with this fan situation I decided to install a fan like Bob Hunt has in his trailer. I was going to go to Camping World in the morning and buy a fan like Bob's and not use the one I have (it will not fit in the bottom section).

I went out to get things ready for an early start tomorrow and I realized I don't have has much clearance as Bob. My gas line sticks out a lot farther than Bob's gas line (see his picture). I can't put a fan in the bottom.

That was the final straw. I got out the drill and drilled out the pop rivits on the upper vent cover. At that point I figured if I mess it up I'll just take back to Casita and let them fix it.

So far, so good. The vent cover is off without damage. The fan is temporarily wired and running. The vent cover is held on with tape. I'm going to monitor the situation for a few days - watch the temps - open the fridge door and then see if it recovers, etc. If all is well I'll permanently mount the fan and reseal and rivit the vent cover back on.

I'll post a picture when it is finished.

Bill

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The fridge worked very well today and it was very hot outside. Yesterday I had the fridge on max. Today I had it on 4 and later turned it down to 3. Temp stayed under 40 all day. I opened the fridge door a number of times. Each time the fridge recovered very quickly. The fan seems to be making a world of difference.

When you take off the vent cover you can see some design problems. Most obvious is a variation between the Casita design and the "Almost Good Venting" shown in Michael's picture. The vent opening is not above the cooling unit as the picture says it should. There is also only 1 baffel in the Casita design.

I did not use a thermostat. Instead, I drilled a hole in the wall between the fridge and the under sink cabinet. I then installed a toggle switch. To turn on the fan I just open the cabinet door and reach in and flip the switch.

I am going to monitor the performance for a few days before I reinstall the vent cover.

Many thanks for all of the opinions and suggestions.

Bill

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Bill,

Did you mount the fan at the bottom like Bob did? Or did you find a way to mount it at the top?

This is Bob's photo - fan mounted at the bottom.

Michael - Atascadero, CA

Fan Installation

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Michael,

I could not mount the fan the way Bob did because my gas line extends out about 3-4 inches farther than Bob's. It was in the way for any kind of lower section mount without re-plumbing the gas line.

I mounted the fan on top of the baffel. I used brackets that used for roof trusses. I will post a picture. I'm also going to try to secure the fan from the top if possible.

I will post a picture tonight or tomorrow.

Bill

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Here is a photo of the fan I installed in the upper vent. The brackets are for roof trusses. Not very pretty but they allowed me to raise the fan to be a little more centered in the hole. The brackets are screwed to the baffel and the fan is rivited to the brackets. I'm going to try to find a way to fasten the fan from the top before I close it up.

Day 2 and the fridge is working fine. I came home to 106 in the trailer and 36 in the fridge with the control set on 4. I opened the fridge door and let the temp go above 50. Within 15 mins the temp was back to 38. Before installing the fan the temp would not have recovered until a few hours after sundown, if at all.

Upper vent mounted fan

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Instead of using a thermostat, I installed a toggle switch in the wall between the fridge and the under sink cabinet. The heavy wires at the top are the new 10 gauge wires I ran to the fridge. The lighter wires are the old wires to the fridge. I use them to power the fan.

Fridge Fan Switch

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Wow! Nice fix, Bill. In the 30s when it's in the 100s. Wow! Which way is that fan pointed? Does it blow onto the coils or exhausting away from the coils?

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The fan blows away from the coils. I can hardly believe the difference in performance. Before the fan, if I opened the fridge door I would lose about 5-10 degrees and the fridge could not recover until the evening. If I opened it again, the same would happen. Now I can open the door for a few seconds and then close the door. I can then watch the temp on the digital thermometer initially rise about 5 degrees. But in less than a minute it starts to drop and will go back to the temp that it had before I opened the door within 5 mins or so.

The fan is a Sanyo but I saw one just like it at Radio Shack ($18.99) when I went in to buy the switch. Radio Shack had the fan in AC and DC models.

The Dometic tech wasn't very good about showing up on time, but he sure knew what he was talking about. He identifed the problem in less than 5 mins without using any tools. He felt the top of the fridge and said it was too hot. He then felt around the vent. He said the hot air was not moving out and was backing up into the sides of the fridge. Three other Dometic techs missed the call.

He also told me how to rewire the DC wiring. I've rewired it but have not tried running on DC yet.

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Bill, you stumped me on "rewiring" the DC. How would you do it other that through the terminal block provided by Dometic? Sure like to know before Thursday morning. Thats when I take my Casita back to be rewired with 10 ga. The fan do make a difference. I had rather have mine at the top but diden't want to remove the vent and re-rivet. May do that anyway. I'm keeping my eyes open for another type vent that can be used on the upper side.

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Wow, I just use a ac/dc fan that I plug into my extra socket in the refrigerator cabinet. I then prop it so it is blowing up and out. My refrigerator does not get that cold though...

I am testing mine right now for a two-month trip for my trailer coming up in a week or so.

Eric

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Bob,

The Dometic tech told me to wire the fridge directly from the battery. He said to also put a fuse on the line. I have it wired but I don't have a fuse in the fuse holder yet so there is no current. I've been so busy at work and messing with the fan that I haven't had a chance to try the 12 volt wiring.

Bill

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Eric,

When I got home today it was 100 outside, 105 in the trailer and 34.5 in the fridge with the setting on 4. I opened the door and the temp recovered in a few minutes. I have never seen the fridge work so well. I highly recommend an exhaust fan.

I figured that was enough testing so I shut it down and reinstalled the vent. I was pretty sloppy with the caulk. I don't have a delicate touch, but it should not leak. I'm taking to Houston in a few weeks. That should be a good test.

Two month trip? Sounds nice. Have a good time.

Bill

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Two months, but only my trailer will be gone that long, I will only be gone about 10 days in October (my buddy is using the trailer the first half). I got my fridge down to a nice chill in about 3 hours, so mine is still cranking okay with the setup i'm using. I just wish I had a better fan setup, so when I get back I may change it to the way you set it up.

It's too bad that fan doesn't come standard equipment with Dometec refrigerators.

Eric

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Wonder if you'd get the same effect by "hanging" the fan on external or outside of the top vent and using alligator clips to attach to the refer's dc connections.

We've never had a problem with any of our refrigerators ... except having lettuce and veggies freeze. In extremely hot weather, we just crank up (down) the temp setting. Problem then is, at night, when it cools down, stuff freezes if you don't lower (raise) the temp setting.

But it would be nice to have a fan to put on the outside of the vent for extended long-term hot weather stays ... and some down and dirty way to connect it to power.

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Well, in the morning heading out for Rice for my rewiring job, and other mods. I measured the upper refg. vent and its the same size as the lower vent/access. Im going to find out if the lower vent can be put in the upper vents place. I think that would give more circulation. The sq/in of opening in the lower access panel is more than in the upper vent, and would allow easy access to the upper part of the refrig. Charlie, I found a squirrel cage fan on the net that was about 12" long for $25 that looked like it would set right on the baffel. It was 12vdc/.5a/6w. If anyone would like the web page I'ed be glad to send it.

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BTW, forgot, the squirrel cage fan was 44.1 cfm. That should provide good air flow and not effect the gas burner.

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I'm wondering if you can reach in the back after you remove the upper vent and seal up the top angled-baffle so that the heat won't reach the top of the fridge inside the Casita.

I have the same cooling problem too. I just returned from the Dometic dealer in Dallas and they replaced the thermostat (they had to remove the fridge to do it). Still barely working on the road and it takes until late evening before it really cools down. But then I have to turn it down to 3 during the night so it doesn't freeze. But the minute we are on the road again, it won't cool like it should and it isn't the size of the wire causing it, because I used gas too.

But it is making sense now that I see how I can't get it to raise in temperature on the road. That's because there is nothing forcing the hot air to the outside. Because when I go inside, I feel the top of the fridge and it is hot. So the heat is staying inside while we drive and the fridge is not cooling very much.

I would like to look to see if the top angled damper can be sealed so that the heat cannot pass to the fridge on the inside. If not then I'm installing a fan up there too. I use one down below, but if doesn't force enough air up.

Any comments on this idea? Bob Steffen

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Bob, after seeing the inside of Bills refg. with the upper vent removed, there's not much telling how its baffeled. I would like to see a curved sheet metal deflector from side to side and sealed, and to be certain the baffel was the * inch of the coils, the way it should be. His looked like it went from side to side, but some may not. It depends on the installer on the assembly line, and what he picks up. Then again, everyone may be alike. Thats why I would like access to the top and any given time. It appears that heat build-up is the problem. The top of my inside cabinet also gets very warm, not hot, but feels like maybe 120 or so. The baffel looks like an ideal place for the squirrel cage fan I found to set. Its about 16" long. Something has to create a postive updraft to get the heated air out.

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Bob & Bob,

I'll post the remaining pictures I took will the vent cover was off. I put the cover on last night so I can't take any more.

Hope these help.

Bill

[Image]

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Pic no. 2

[Image]

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Pic no. 3

[Image]

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Bill,...and Bob below

Thanks. I see in your bottom (last) picture as I saw into mine today that the angled baffle is just attached except by the bottom and the top and not on the sides. Your picture shows that and I saw it in mine. You can see, in your picture, the brown (back side of fiberglass)next to the carpet and this difference in the thickness of the carpet allows the heat go into up and around to the front of the fridge.

I'm almost 100% certain that is my problem and probably many more Casita refers have the same problem. It just depends on how tightly they build the angled-baffle to the sides. Casita needs to seal the sides up.

I was just about to give up, but seeing you fix your problem really makes me feel good.

That's why it takes a long time to cool down when I hook up in a campsite, because there is no way to get rid of the heat trapped inside the fridge cabinet (it is all opened in there), until you put a fan up there like you did. My fan down below, only forced more hot air up around the angled baffle and in on the top of the fridge.

BOB, thanks for the input on the squirrel cage fan. I don't know what direction, I'm going yet, but I want the fan to push as much air and draw as little current possible, because I'll use it on the road when operating on DC -- AN this is where my problem starts.

Bob Steffen

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I might try that expandable spray foam and see if I can reach around the sides and completely seal the heat off from going on top of the Fridge (refer to some). Thus forcing it to go outside. Thanks for the extra photos, Your thoughts? Bob Steffen

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The top of my fridge was very warm before using the fan. I guess the hot air was trapped there. It is much cooler now. The type of fan that Bob Hunt has ( Fridge Mate Coil Fan, CW # 1459)would mount very easily on the baffel. You probably would not need any brackets like I had to use. It is designed for side vented refrigerators.

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If you use a 12" long fan you could put yourself in a position where you always need a fan. When the temperature is moderate my fridge works fine without a fan. However, a big fan in the vent may block the air flow enough that you would always need to have it turned on. When I was testing, I turned the fan off at night and the fridge was fine (although I didn't open the door). The temp even went down to the high 20's. You might have to run the big fan all night. Could be noisy.

Just a thought.

Bill

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Bill, What size drill bit did you use to drill out the pop rivets? What size rivet did you put back in? I have a variety bag from Casita but not that many of one size. Where did you buy them from? I have a gun.

Yes the 12 inch may be to large.

Bob Steffen

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I will check the drill bit tonight. I know it was small. I didn't want to risk making the hole in the vent any larger. The vent is very thin and you could bore out the hole very easily. You don't need to drill all the way through, you just drill until the head of the rivit breaks off. Then you can push the end of the rivit through the hole.

I did not buy the rivits. The last time Casita worked on my trailer they left a grab bag of rivits and screws in the trailer. I tried different rivits until I found one that fit. However, they were the smallest rivits in the bag. They need a fairly long shank to go through the fiberglass and catch on the inside when you install them. I can measure one for length tonight but it might be better to call Casita and get the exact rivit size. I would not be able to measure the diameter. The next time I go to Home Depot I can take one of the rivits and match it up with a size and post it here in case someone else wants to install a fan.

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Thanks Bill, I can probably do the same once I drill out the rivets. Didn't know you just drill the head off. I thought you had to go all the way through. Thanks for the tip. I'll wait till I hear what size bit you used. It might save me a couple of bad holes. Ha Ha Bob Steffen

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Bob, I used a 9/64 drill bit. I had no problem with over drilling. Bill

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Bill, Thanks. I bought the fan today from Radio Shack and I bought 2 cans of the expanding foam (minimal and triple expansion). I'm going to seal it off to the fridge so that the heat has only one place to go -- out.

I also bought a switch (Radio Shack) that has a very small pilot light so I can tell when it is on. I going to install the switch on the front of the sink cabinet down real low towards the floor (1" dia hole & pop-in the switch).

I don't know if anyone would be interested in seeing pictures of my job since yours were excellent. But I might take some if I can be successful in sealing around the angled baffle.

Thanks for your help Bill, I know this is going to work. Never could figure out why it wouldn't cool on the road and after we stopped for the night. It always took a long time for all that heat to get out of the top of the fridge and then it cool great.

MAIN PROBLEM. . . The vent just doesn't draw enough hot air out when you are driving and has too many leaks to the fridge box.

I always wondered why the coils, on the back, were so warm/hot and the top of the fridge was warm. They should be warm but not that warm and the top of the box shouldn't be warm at all. The design that Casita has right now is just not efficient enough.

Bob Steffen

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Bob, Glad to help. The Dometic guy identified the problem. He just didn't come back to fix it. I would to see some pics. You can email them if you think we have enough pics on this thread and no one else is interested.

Bill

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Bob S. put your pics up. I'm interested and would like to see them. I'm picking my Casita up tomorrow (24th). The have put the new 10ga wire to the refrig. replacing the 14ga. Also, having the new battery slide installed. Will pop a pic of it up Saturday. The slides really nice and and makes the battery easy to get to. Also ordered me a EU2000i generator today. Now, anxiously waiting on it. I met "John" at the factory today. He's a really nice guy. They was having some work done on their Casita. Man, they have trailers running out their ears. The lot was FULL and a big baloon with SALE on it flying about 150 ft. in the air.

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Okay, Bob, I'll do it! That's interesting that the factory is putting in 10 gauge wire for you, they found that I had one 14 gauge and one 12 gauge and only replaced the 14 to a 12 gauge. I tried to talk them into replacing it with 10 gauge but they said no. Do they have slides for the battery -- how much does it cost to be intalled. It is a bear to get it out (#27 type) to check the water.

Oh, how I want one of those Honda generators, but I have to sell my 5000 watt on wheels generator first. It has barely been used. Of course it is a much heavy type than the Honda and we certainly can't take it with us. It is primarily for home use. It was purchased last year when we had power outages.

Will take some pics, Bob Steffen

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Bob, both of my wires was 14 ga. They said they have tested them at the factory, and 12ga was heavy enough and thats all they would replace them with. I reminded them that Dometic notes using a 10ga. After insisting on it, he conceded to installing the 10ga. The battery slide? It' made out of very heavy wall alum. angle. I only looked at the assembly installed on another trailer. I'm going back after it this morning and will post some pictures late this evening. Cost? Reasonable. $35 and one hour labor @$35. Certainly can't fabricate one for that, including all the flusteration. I had a Coleman 5000W when I lived in Van, but sold that when I moved here. It was on wheels and too bulky to move around. But, being a gentleman farmer, it came in handy. Generator? The local company here that sells them quoted me $1,079.00 plus the 8*% tax. I ordered it from Northwest Power Tools, located in Washington state. It was $885.00 with free shipping and no tax. I did order the 12vdc battery charging cable to, that was $9.95. Run your generator in the Nickle paper. I've used it with good results. Bet you it would sell. Have a good day and stay cool. :-), 103 here yesterday. We passed the 30 day mark with temps. over 100 and no rain except for a *" shower once. Diden't even settle the dust.

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I received a call today from Dometic. They were trying to find out the status of my fridge. After bringing them up to date on the fridge they offered to extend my warranty by an additional year. Considering that the problems with the fridge were from the installation and not the fridge itself, I thought the offer was pretty good. I certainly wasn't going to turn it down.

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