Norcold refrigerator questions

[KalaKai]

I have a 2010 Norcold 61 series refrigerator/freezer. With a/c and d/c on, all is well, cools fine, but...when d/c breaker is turned off, the unit turns off. I would prefer to run on a/c when at the dock. I can't tell if it's running on a/c or d/c, but assume it's running on d/c since when I turn d/c off, it turns off...though it may just have to have both connected for it to run even if it's only running on a/c.

Another strange thing is that when I unplug the unit from a/c, it turns off (with d/c on), but if I turn off the a/c breaker, it stays on.

a/c on - d/c on
* works fine
* unplug a/c, unit shuts down
d/c off - a/c on
* until shuts down
a/c off - d/c on
* works fine

any ideas would be appreciated...

 

[kchace]

It sounds like the breaker you think is for the Norcold is not the one that is actually controlling it. Otherwise, unplugging or turning off the breaker would have the same effect. Unless perhaps it is being fed by two different AC circuits which if you didn't know about would make for some difficulty troubleshooting.

Ken

 

[KalaKai]

It sounds like the breaker you think is for the Norcold is not the one that is actually controlling it.

If I turn off the master a/c switch or the fridge breaker, same effect....the unit continues to work (still on d/c). All a/c to the boat disconnected, unit runs on d/c fine, but....

If I unplug the a/c cord, the unit stops even though d/c still connected.

I don't have an inverter.

and

If I turn off the d/c breaker for the unit, it stops working.

I know there has to be something real simple I'm missing.

 

[wwestman]

The hard way would be to pull the box or get access to the back and check the two outlets (ac/dc). Are you sure that it has an ac set up? In my case I have only dc even though both circuits are run to the cabinet.

The easy way is put a guard over the dc breaker so that it does not get turned off and run it on dc all the time.

 

[KalaKai]

The hard way would be to pull the box or get access to the back and check the two outlets (ac/dc). Are you sure that it has an ac set up? In my case I have only dc even though both circuits are run to the cabinet.

The easy way is put a guard over the dc breaker so that it does not get turned off and run it on dc all the time.

I did pull the unit out and checked a/c voltage, it was fine. That's how I found that disconnecting the a/c plug turned the unit off. This happened whether the a/c plug was hot or not.

turning off d/c always turns off the unit

with d/c on, unit runs whether a/c current or not, but shuts down when I unplug it...bizzare

 

[kchace]

If it runs on D.C. when you are certain that the AC to it is off, but shuts off when you unplug the AC then it could be using the AC ground as a return path for the DC. It could be an internal power supply problem, but it is starting to sound scary. I would disconnect the AC completely and carefully check the D.C. wiring. Then do the same in reverse.

Ken

 

[Edelweiss]

Yup, I agree somethings not right there.

I have the same Fridge, 2014 model, and I just checked it. I can hear the compressor speed change when it switches between DC and AC. I can't easily unplug it, as it's in a built in, but turning the breakers off and on, DC and AC, one way and then the other, it's pretty obvious.

Like the previous poster said, could be a ground issue or an internal switching problem with the fridge controler. I would definitely have it checked out.

 

[C lectric]

Hear speed change?
The DC may need an adjustment for frequency.
On my very much older Not cold I heard that when unplugging AC. and after checking found the oscillation was off by 6-7hz. After adjustment the unit ran much better, dropped current approx. one amp and cooled better.
Don,t know if you have same control but might be worth checking into.

 

[C lectric]

Again my much older Norcold may be different from yours.
Could be the AC side is not working at all even though plugged in.
On my old unit there was an AC relay that activated immediately disconnecting the DC ,immediately connecting the AC,. even though DC was on. Thus the fridge then ran on AC.
When AC was disconnected and DC available the fridge then ran on DC.
If that relay failed it would run on DC regardless of whether AC breaker was on which may be what happened.
See if you have the relay and ensure it is actually operating properly.

 

[Benthic2]

I believe some air conditioners have a feature where if the power is cut, they will not turn back on right away. It has something to do with protecting the compressors....could something like that be at play here muddying the waters a little ?

 

[Peter B]

I suspect this fridge runs on DC all the time. In other words, when plugged into AC, all that happens is the drain from the DC (battery) side of the supply is tripped out, and the unit then just converts 120v AC to 12 v DC directly, thus saving battery drain. When AC is shut off then it reverts to drawing from the batteries. Not sure if that explains the situation, but that is what I think should happen anyway.

However, if it stops when you unplug the AC cord, which I presume is just the one from the fridge to the AC outlet on the boat, and not the AC power supply at the berth pendant, then it suggests that the unit is sensing the batt voltage a bit low and activating the battery drain protection, or somehow needs that plug in to complete some essential circuit that allows the switch from DC to AC to occur..? Hopefully one of the more electrical scavvy members will come in on this thread soon.

 

[what_barnacles]

Is it a N61(X) series? I could only find that on thetford, and the manual indicates it runs on propane.

The AC is used to power the refrigerant heater, otherwise it will use propane to heat it. That refrigerant and the cooling system in general has had tons of recalls. Lots and lots of RV's have burnt up from the cooling line cracking and the ammonia catching fire. Here's a copy of the recall, you can call in and see if your model is affected. It's free if so. http://www.thetford.com/wp-content/uploads/2015/03/Norcold-Recall-Notice_11_02_10.pdf

The 12V comes from a separate connection and isnt derived from the 120VAC. It uses 120 to electrically heat the refrigerant, OR 12V to heat it via propane.

 

[Heron]

could be the AC side is not working at all even though plugged in.
On my old unit there was an AC relay that activated immediately disconnecting the DC ,immediately connecting the AC,. even though DC was on. Thus the fridge then ran on AC.
When AC was disconnected and DC available the fridge then ran on DC.
If that relay failed it would run on DC regardless of whether AC breaker was on which may be what happened.
See if you have the relay and ensure it is actually operating properly.

Exactly how mine works (vintage '88). My AC for the Fridge is just a hidden outlet wired to the other AC outlets on the boat with only one breaker for all of those. Turn that off or unplug from the dock, then I must throw a DC switch to keep the fridge running.

 

[kev_rm]

On my very much older Not cold

See I give mine slightly more credit than that I call it "Hot Nor Cold"

 

[C lectric]

Actually that old Norcold worked very well. It was replaced for two reasons, it was heavy on power and the most important was a larger fridge was wanted.

The only time it gave trouble I figured out it needed a frequency adjustment after which it continued to work well. The tip off was the running speed change when I went from AC to DC power.

Doesn't matter much now since the new unit has the Danfoss BD35.
But if the OP unit has the SWING motor then there is quite likely that relay and a frequency adjustment.

 

[Edelweiss]

Is it a N61(X) series? I could only find that on thetford, and the manual indicates it runs on propane.

DE0061 Norcold AC/DC