Norcold 1200 fan tweak

footdoc · 11-14-2010, 04:08 PM

I WAS thinking about a residential refer mainly because mine just doesnt work as well but will stay in the upper 30s to 40 ish on a hot day but the freezer doesnt get below +10..but I want to tweak the air movement behind the box...both of my standard fans work as designed but Im thinking more is good in this situation...the fans are located right above the condensing tubes and blow upwards...I think they are 120mm fans at about 100cfm at 38 dB...each
I've been checking into 12v fans that are pretty quiet and have found several 120mm fans that will blow 70+ cfm at a lower noise level...
I want these 2 or more added fans to have a manual switch. Any suggestions on where they SHOULD go? There is very little space between the outside wall and the condensing tubes, but MAYBE enough to mount a fan to the wall blowing directly onto the tubes...or maybe from below the tubes going up and another above the tubes and the original fans to push more air out the top vent...it's not in a slide out...I'm thinking the 2 provided fans are either not in the best place or there needs to be more of them...your thoughts??? I KNOW if/when this refer dies, I will either get a residential or the Amish cooling unit everyone raves about...no more Norcold and it's associated problems/hazards...

KIX · 11-14-2010, 04:22 PM

We have the Norcold 1201 and I have added a 3rd fan with both manual operation and t'stat operation. I mounted it at the top of the lower access door. On my coach I only had room to mount it tilted. It tilts toward the back of the box and blows upward. We live in Florida and the really hot weather was over by the time I got it installed so I can't say with certainty that it helps to any degree. But, logic tells me that it's got to help. Good luck

AFChap · 11-14-2010, 04:26 PM

Fans typically PULL better than they PUSH ...but since there are already two fans on the top of the tubes pulling, I would mount fans on the bottom of the cooling tubes to push air upward through the cooling unit. When I found my fans were not working last Summer I put a 120v fan under the cooling unit pushing up and it made a noticeable difference ...service techs had hooked up the 12v leads backwards and the fans do NOT operate on reversed polarity...

I had my cooling unit replaced one year ago this month, and got a Norcold replacement. It works now better than it EVER did. But, I agree that if it goes out again a residential refrigerator will most likely be the replacement.

TheRVGuy · 11-14-2010, 04:48 PM

The best place to install fans is at the highest point near the evaporator at the top of the coil. I mounted 2, 3" radio shack muffin fans just below the wire screen that you will find under the roof top vent cap. It is an easy wire pull to get 12V up there by pulling up along the left side of the refer as you are looking at the back. That will place the wire away from the heat stack on the right.

Once the pull is up there, the thermo switch is up there too, if you want to tie into it. If not, placing a switch and wiring it into the coach is pretty straight forward. Be sure to fuse the positive side.

To repair the screen that you will cut with scissors can be done with light wire ties. You will just lace the wire back into place with the wire ties. I typically leave about a 1/2" space of wire screen around the edges of the vent to allow the reattachment of the screen that is cut loose.

After do this modification, our freezer regularly achieves -5 or better. The coldest place in the freezer of a 12xx Norcold is in the left freezer, bottom left corner below the ice maker.

Hope this is of assistance.

Mike

Paul T · 11-14-2010, 07:16 PM

I’m just wondering where the airflow really counts and believe it may by passing the condenser as much as passing by the absorption tube area. Norcold’s trouble shooting suggestions and installation guideline refer to very close spacing where the air is channeled past the condenser. I found my installation far from that specified by Norcold from a ventilation standpoint and have corrected the baffle near the condenser. Next is a thorough testing to see if the cooling has improved. Food for thought as you increase airflow with additional fans or increased airflow in that it probably needs to be focused on the right components.

Dr4Film · 11-14-2010, 08:17 PM

Quote:

Originally Posted by footdoc

I want these 2 or more added fans to have a manual switch. Any suggestions on where they SHOULD go?

FootDoc,

I have personally spent the last three years trying to solve multiple problems with my 2001 built Norcold 1200LRIM. With the help of a few people on this forum, I have been able to resolve almost all of them and now have a really great working Norcold for now. I still need the most recent recall to be installed and that should be done in a week or two.

Without going into a very long story about everything, you can search all of my Norcold Posts to read about it all here at iRV2. However here is a short synopsis of what I have done.

To resolve the erratic temperature swings I had for 3 years, I replaced the Thermistor. The old one had been tested 3 times and each time was told it was OK. It had an internal dynamic failure that caused my large temperature swings. I have installed two sets of 12 volt mini cooling fans inside the frig compartment to the fins above the top shelf. This distributes the cold air more evenly and prevents the frost and ice from building up on the fins. They are available from a gentleman on eBay. Here's the link. They are just over $17 with shipping and are fully guaranteed. He usually runs a holiday special if you buy two.

DOMETIC NORCOLD REFRIGERATOR FAN FOR RV 12 VOLT: eBay Motors (item 250677760674 end time Dec-02-10 14:37:30 PST)

The most recent change was while I was in Alaska this past summer, my two OEM rear cooling fans decided to start making such a racket that I had to disconnect them. Obviously either the bearings gave out or a plastic fin had broken off allowing the fan to vibrate terribly. I ended up installing four 120mm cooling fans on the rooftop vent and wired them into the existing snap disc circuit so they would come on at the same temp, 130F when the #1 fin at the top of the cooling stack got to that temperature. I also included an additional wire so I could install a manual switch which is now inside the Norcold rear access cover. I use that when I want to have additional airflow other than when the snap disc calls for it.

I have been able to keep the temperature setting around 5-7 depending on the outside temps, and the freezer is normally -4F to 10 F and the frig is 29F-39F depending on whether the frig is in its defrost cycle or not.

I am very happy with the outcome and hopefully will have many years left in this 9 year old Norcold. If the cooling unit does fail, I intend on putting in an Amish built unit or a residential unit.

No more Norcold for me.

I have included a few photos of the internal and extenal fan projects. If you would like more photos and more detail, please PM me as I have done a complete write up for others about the rooftop fans.

Dr4Film ----- Richard