Why does my Norcold 2-way turn on so much?

dnordahl1

I've been trying to understand why if I don't open the door for 8 or 10 hours why it comes on so much. I've used a thermal camera on the door seals and see no cold escaping. I've pulled it out of the cabinet to see if any holes into it aren't well sealed and didn't see anything. It seems very well insulated. 

I usually keep it on a 3. It keeps everything cold. Independent of how well or efficiently the compressor or fan is working or what cold setting its on, I don't understand why it needs to come on so much. Where is all the cold going?  Does the refrigerant thermosiphon it away then when the compressor doesn't run or something? I really would like to know what the design issue is and if it can be overcome somehow.  

pthomas745

"On so much" meaning..what?  it is normal for any fridge to cycle on and off.  On my small "portable" 2 way fridge, the 'duty cycle" came out to be about 5 minutes on and 12 minutes off...consistently. 

Are you seeing quite a lot of power draw/battery drain?  The group generally says the 2 ways use between 24 to 30 amp hours.

Have you tried timing the duty cycle?  How long does it run, and then how long until it starts running again?

XenanMe

I have a 2018 400 and the 2-way fridge cycles on approx every 15 minutes in warmer weather (set at 3).  It runs for about 3-4 min each time.  It used to drive me crazy at night because it isn’t very quiet.  Now I use a white noise device to drown it out at night.  

Marceline

dnordahl1 said:

I've been trying to understand why if I don't open the door for 8 or 10 hours why it comes on so much. I've used a thermal camera on the door seals and see no cold escaping. I've pulled it out of the cabinet to see if any holes into it aren't well sealed and didn't see anything. It seems very well insulated. 

I usually keep it on a 3. It keeps everything cold. Independent of how well or efficiently the compressor or fan is working or what cold setting its on, I don't understand why it needs to come on so much. Where is all the cold going?  Does the refrigerant thermosiphon it away then when the compressor doesn't run or something? I really would like to know what the design issue is and if it can be overcome somehow.  

I guesstimate that the compressor in mine runs about 30% of the time. I use  this bluetooth thermometer to track the internal temperature of the fridge without opening the door and adjust as needed. 

You're not asking unreasonable questions, but they are pretty technical, so I'd send them directly to Norcold.

dnordahl1

I think the amount mine runs is the same as what your comments mention. I'm just not clear on why the consistent off 12 minutes, on 5 seems to happen regardless of how much it's opened.

 I have a refrigerated cooler that rarely cycles once it's down to temp unless the door is opened. I've seen insulated 5 day coolers keep ice cubes unmelted for over 5 days sitting outside on a hot porch in the summer. Both of these things have similar insulation as the Norcold, so I just want to understand how it loses so much cool. 

Bayliss

@dnordahl1, I'm not familiar with the 2019 T@B 400 layout, but does your refrigerator receive fresh air and vent warm air inside the trailer, with no external venting?  If so, maybe it is not necessarily losing a lot of cold temp, but rather dropping down slightly, maybe even one degree or two, so the fan/compressor kicks on??  Just a guess since I can't come up with any other explanation.

dnordahl1

@Bayliss That's probably the case. Perhaps the heat from the compressor and condensing coil from the previous cycle doesn't ventilate. This causes heat to radiate upward into the unit since there's no ventilation or fan running to cool those parts and disperse their heat after a cycle ends. 

dnordahl1

@Bayliss I think I'm going to run an experiment by placing one of this small blower fans inside the bottom grill.  If steady air flows over the condensing coil and compressor is present, maybe it will reduce how much it comes on.

GDSTIME 50mm USB Fan, 50mm x 15mm Blower 5V DC Brushless Cooling Fan https://a.co/d/bQy846x

Bayliss

Sounds like a plan, @dnordahl1.  I've never seen that type of fan, but it is an interesting configuration.

I recently installed a dual fan system in an enclosed cabinet of my entertainment center, which contains a TiVo DVR and an NVR security system video recorder.  Neither produces a lot of heat, but I did need to supply some air circulation since the cabinet is fully enclosed (other than slight openings around the cabinet doors.)  I like the system (which is AC powered), because one fan blows air into the cabinet, while the other blows air out of the cabinet.  The system includes a digital panel and a thermometer probe that turns on both fans when it reaches the temperature setting I selected.

rfuss928

I used a 12v version of the 50mm fan dnordahl1 mentioned.  I installed two behind the top vent panel of the Norcold in our old CS.  I powered them from the compressor leads so they ran when it ran.  I really didn't notice a difference in the refrigerator duty cycle but I was more confident it wasn't due to heat build up in the cabinet.

AndreO

I have a 2018 400 and have spent lots of time playing with the fridge efficiency. Including putting fans both inside and behind it, with lttle success I may add. The fact is there are many factors that can effect it. IE: Are you on battery or ac. The fridge compressor will not operate below 11.2 volts but the fan will, making you think its cooling yet cycling constantly. An AGM battery voltage drops quickly as it discharges.

So it's hard to say what the issue could be without much much more detailed info.

However the one thing that seems to have the biggest effect on all aspects of its functionality is the ambient temperature inside the cabin. The cooler it is inside the trailer the less it will cycle and cooler it will be in the fridge.

dnordahl1

I upgraded to lithium so I'm never really below 13v. That is actually one other thing that I've found odd is that I can be camping in pretty cold weather with my cabin temp also pretty low, and it still seems like it's cycling on about 30% of the time even after not opening the door for 10 plus hours. 
Anyway I recently started setting the dial to 2.5 instead of 3 when I'm on batteries and it seems to run way, way less. I'm also going to start putting ice packs in the freezer when I'm plugged in our when solar has my batteries mostly topped off. Then move them into the fridge compartment when it's overcast or shaded. 
I'm hesitant to put meat in the freezer at that setting. I need to just get one or two wireless thermometers.
I noticed the Isotherm fridges have the compressor and condenser coil on top instead of underneath. That makes more sense for placement to me.

Marceline

dnordahl1 said:

I upgraded to lithium so I'm never really below 13v. That is actually one other thing that I've found odd is that I can be camping in pretty cold weather with my cabin temp also pretty low, and it still seems like it's cycling on about 30% of the time even after not opening the door for 10 plus hours. 
Anyway I recently started setting the dial to 2.5 instead of 3 when I'm on batteries and it seems to run way, way less. I'm also going to start putting ice packs in the freezer when I'm plugged in our when solar has my batteries mostly topped off. Then move them into the fridge compartment when it's overcast or shaded. 
I'm hesitant to put meat in the freezer at that setting. I need to just get one or two wireless thermometers.
I noticed the Isotherm fridges have the compressor and condenser coil on top instead of underneath. That makes more sense for placement to me.

I’m really happy with the Govee Bluetooth temperature monitor. It’s really helped me get a handle on what’s going on with the fridge. 

Here’s a chart from a recent camping trip. You can see the temp climb from midnight to 9am after I turned the dial down to 1.5 or 2 to minimize the compressor kicking on overnight, but it doesn’t break 40 degrees. I have have the app send me a warning if the temp goes out of a set range. 

AndreO

So what fridge do you have? Where did you place the sensor in the fridge? Do you also have a chart for the ambient temps for the same period of the trailer. I'm assuming it's a a 400.

Marceline

AndreO said:

So what fridge do you have? Where did you place the sensor in the fridge? Do you also have a chart for the ambient temps for the same period of the trailer. I'm assuming it's a a 400.

My T@B is a 2013 CS-S (clamshell) so it has a Norcold 740 in the galley at the back.  It put the monitor at the back of the bottom of the fridge so it isn't too affected by opening/closing the door. I don't have data for the ambient temperature, but it would be easy to accomplish by getting another monitor (they're pretty cheap).

Syd

XenanMe said:

I have a 2018 400 and the 2-way fridge cycles on approx every 15 minutes in warmer weather (set at 3).  It runs for about 3-4 min each time.  It used to drive me crazy at night because it isn’t very quiet.  Now I use a white noise device to drown it out at night.  

We bought our 2019 400 second hand two weeks before lock down in 2020. Our Norcold was quite loud when we first got the trailer. Every time it ran something rattled. It was a light noise at first, but after a couple of days it was really loud. Made for excellent sleeping. Possibly one of the reasons why the people we bought it from sold it.

When we got home from that first trip, I pulled the fridge out to find the loose panel that was rattling. Underneath, near the compressor, there are heat shields. One of them was not attached properly in the first place, so it was the one rattling. I was able to fix it by putting some paper towel folded tightly as a wedge to stop it from moving. Air still moves around it fine and it is not any type of fire hazard because it doesn't get that hot where this panel sits. Now the fridge is almost too quiet. My wife asks me if it is actually running or not.

Mickerly

Our 320CS has the smaller Nr740. I found the leak was in the refrigerator frame. where the door seal meets the box, at the joint between the sides and the bottom, there are gaps. I filled those with epoxy. We run the between 1 and 2 now with it 90 to 100F outside. It made a difference. I'm not sure if you Nr751 is constructed the same, but it is worth a look.

By the way, Accurite has a battery powered thermometer with 3 remotes. We leave one in the 'fridge to monitor and one on a stabilizer jack for an outside reading.

XenanMe

@Syd Thank you for those details.  My noise is a loud “click” followed by a short rattle.  I assume the click is the fan turning on and maybe the rattle is something loose.  I have contemplated pulling the fridge out to look but it always seemed a bit too much effort.  After hearing about how much better yours is now I am putting it on my “must do” list.  

qhumberd

I can confirm that the inside temperature of the trailer makes a difference in our Norcold 2 way. We also have a Govee temp monitor and when the fridge is set on 3 and the inside temperature is below 80 degrees it maintains below 40 degrees. It runs about 4-5 cycles of 3-5 minutes per hour. Temperature climbs to 42 when trailer is hotter and in direct sun. Cycles seem the same. Just wondering how accurate the thermostat is.

the noise of the fan and compressor are not very noticeable to our ears.

Aubrey

My thermostat failed and I replaced it, not expensive. Maybe try that if you have inconsistent control. 

Mickerly

I'm not positive but most refrigerators don't have a thermostat. You set a percentage of on vs off with the control wheel. That's why the interior temperature moves proportional with the interior temperature and the cycles don't change.

That was part of the reason we changed out our Danby air conditioner. We have one with a thermostat now. Much nicer.