Quick Norcold Fridge Question - Page 2

**Mr_funnypuns** · 07-27-2016, 06:26 AM

In my 2720, the heaters are connected to a terminal block inside the fridge compartment. I checked the element by measuring current with a clamp-on Current meter. It should read about 10A when the element is running right.

The top of the coils on the fridge should be warm, and the vent on top of the chimney should be hot when the fridge is running from any source, including 12v

Ford's RV fridge school has a bunch of helpful YouTube vids here:

https://m.youtube.com/user/FordRVRefrigeration

Theory of operation is here:

https://m.youtube.com/watch?v=oIJYx5j2nPQ

Padgett · 07-27-2016, 07:04 AM

Fridge on DC will pull near 10 amps (resistance heating of a GA is very inefficient). Will kill a standard 12v battery in a few hours.

I keep several blue "Ice Packs" in the home fridge to jump start or keep a cooler cool.

**Mr_funnypuns** · 07-27-2016, 07:10 AM

I only use DC mode for travel. 200w of solar on top does a pretty good job of keeping the batts from running down. Blue ice ice more efficient, however for short trips, I just freeze water bottles. Then I have cold drinking water when I arrive.

**inghamm** · 07-27-2016, 08:32 AM

Quote:

Originally Posted by Shane826

Well we had closed it up on DC power and plugged in, setting 4. It was mid 70s last night. When we got to Darien Lake 10hrs later, the fridge was barely cool. I guess I don't get these absorption fridges. I almost want to put an AC/DC compressor fridge in its place. We don't boondock at all so the propane feature is moot.

Did you turn on the fridge fan before you closed down the trailer? (Its with the battery level and gray water level gauges under the sink) It helps keep the absorption area cool while the trailer is closed. Did you run the fridge on AC to cool it down, pack it with already cold food before switching to DC? These are tips I've gotten from reading the forum.

tentcamper · 07-27-2016, 08:38 AM

I know the 120v heater is 180 watts. Not sure about 12V, but heard it draws about 10 amps. At 10 amps it would be around 125 watts. Not to good for a fridge designed to work best at 180 watts.

Shane826 · 07-27-2016, 06:07 PM

Quote:

Originally Posted by inghamm

Did you turn on the fridge fan before you closed down the trailer? (Its with the battery level and gray water level gauges under the sink) It helps keep the absorption area cool while the trailer is closed. Did you run the fridge on AC to cool it down, pack it with already cold food before switching to DC? These are tips I've gotten from reading the forum.

I opened the camper, packed sleeping bags & chairs etc, turned the fridge to DC level 5, turned on the fan, and closed it up. Fridge was empty as I had to go shopping in the morning before leaving. The camper was also plugged in to a 20A outlet in the garage. This was around 2am Tuesday. We arrived at Darien Lake around 3pm Tuesday, set up camp, and the fridge was barely cool. I always carry drinks in the ice-filled cooler so I had my yogurt, cheese, cream cheese, fruit, and s'mores chocolate in the cooler with the intention of putting them in the fridge. Switched the fridge to AC plugged in to shore power and the fridge was cold (but not cold like the fridge at home) in a few hours. Freezer wasn't much colder than the fridge, at least by touch it wasn't. Put the groceries in the fridge overnight. Went to have breakfast this morning and everything felt cold but the cream cheese and yogurt had an odd taste...

I need to read up on how this voodoo device works.

LoveToCamp · 07-27-2016, 08:14 PM

The absorbtion fridges only cool to about 40° below ambient temp. So, during the day, if it is 90° outside, the fridge may only cool to 50°. I have found it helps tremendously to take the vent covers off the side of the TM, behind the fridge. Doesn't look as nice, but it helps keep the fridge cooler, as more of the hot air escapes the cavity behind the fridge. Also, an empty fridge doesn't cool much, as it is trying to remove head from air. Very inefficient!. Even if you just put bottles/jugs of cool water in the fridge when you turn it on, it will cool better.

Not ideal for summer camping. We keep dairy products in a cooler with ice. But, since we camp in the mountains, overnight I can get the fridge down to about 32°. Our freezer always freezes. I have mine on now (turned it on last night). It was 95° today, but my freezer has solid blocks of ice in it, which were water last night. Fridge, well, is only about 40° now (I have my vent covers off). No direct sun on that wall of the TM today.

Shane826 · 07-27-2016, 09:16 PM

I guess that makes sense that it will only cool ~40 below ambient, opposed to reaching a target temperature. The first couple times we used it (late last fall and early this spring) we had to run the furnace because it was pretty chilly, and the fridge froze our cream cheese and strawberries. We are just now getting to use it with HOT weather. It has been around 90 the past few weeks during the day.

Has anyone swapped in a compressor style fridge? Results?

**Mr_funnypuns** · 07-28-2016, 04:04 AM

If I remember the wiring diagram right, on dc, the temp control knob does nothing.

The absorption fridge uses heat to distill ammonia out of a solution, then condenses it. As it flows through the coils, it boils, and cools the fridge before being reabsorbed into solution.

This process only works if the fridge is level, and therefore it's important to level the trailer when using it.

Here's another good article on how they work:http://bryantrv.com/reefer.html

**rickst29** · 07-28-2016, 12:12 PM

Quote:

Originally Posted by tentcamper

I know the 120v heater is 180 watts. Not sure about 12V, but heard it draws about 10 amps. At 10 amps it would be around 125 watts. Not to good for a fridge designed to work best at 180 watts.

The power varies according to the input voltage. The AC 'heater coil' has resistance of 67.2 ohms, creating a bit less than 1.8A @ 120v (and therefore, over 210W). The DC 'heater coil' has resistance of 1.3 Ohms, creating about 10.6A @ 13.8V, and a bit less than 150W.

In both cases, the power will go up or down according to voltage-squared. At 14.4 VDC (while charging "bulk") the DC heater puts out nearly 160W. And, during a slight AC "brownout" (or wiring losses) which bring that voltage down to 110V, the AC heater drops to 180W.