Trouble shooting Norcold 1201 - suddenly stopped cooling

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Malibu39

Malibu39

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Joined
Jun 5, 2017
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41
Location
Medford Oregon
I have a Norcold 1201 in my 2004 Itasca Horizon. I have been parked for two weeks, on shore power. First week, the frig worked great. I have an ARP controller installed and noticed that my frig warmed up to 60f, ice melted in the freezer, and my ARP fans were not engaging. Outside temps were in the 90s, but I am full shade. The ARP read that my boiler temp was 175 c, which is too cool as I understand. So wondering if I have a heater failure. No codes on ARP or the frig.

I have not tried it on LP, which should probably be my next step correct? I would but I work during the week and do not have access to my RV. Any other ideas, please fire away.

I have also done the thermistor removal test, and no change. It appears the frig is no longer cooling at all.
 
As you already suggested, run it for a couple days on LP. It does sound like a partial heater failure but the LP check will narrow it down
 
175 C. (about 350 F) is right where the boiler should be, so the heating elements are working fine.  Most probably there is a blockage in the tubing, so no circulation of the coolant.  That isn't repairable either.  Try LP gas mode, but based on your description of the symptoms, I do not believe to will be any different.

However, it is possible that air flow up and out across the back of the fridge is insufficient and the condensor at the top cannot shed enough heat to function. That could occur is a critter has nested in there, or something is blocking the upper outlet. Sometimes the factory leaves a snarl of wiring or does not provide baffles to direct the air, so the flow is inadequate in really hot weather.  Take a look, and maybe try placing an extra fan at the bottom to help it out. Leave the outer access door off and prop a small box or table fan in the opening to push air in. If that helps the cooling, we can talk about a more permanent fix to the air flow problem.
 
Gary RV_Wizard said:
175 C. (about 350 F) is right where the boiler should be, so the heating elements are working fine
Click to expand...


My bad. I had the 350F number stuck in my head and missed that OP posted the temp in C
 
Gary, can you read this from ARP website on heater failure. In particular section D. Sounds identical to my problem. I will be down on Friday to do some more trouble shooting.

The curve to the left is of a Norcold 1211 refrigerator boiler using the ARP Data Collection control. Following is a description of the events captured in this session:

A) The refrigerator goes through a normal cooling period with both heaters connected and working properly. The refrigerator thermostat turns on the cooling unit; the temperature rises, and then holds at about 187?C. The refrigerator cabinet temperature is 45?F.

B) One heater is disconnected, then the refrigerator is allowed to go through 3 more cycles.

C) Note that the maximum temperature is now 192?C on startup.

D) The temperature drops to 179?C rather than the 187?C with both heaters.

The refrigerator cabinet temperature is 67?F after running for 7 hours with just one heater.
 
Based on the ARP site example, are you concluding that the 175 C. in yours means that one heater is out?  All I can say is that I owned a 2004 vintage coach with a 1200 LRIM fridge and an ARP Data Collection module showed that it consistently ran at 355 F (179 C) under normal operating conditions.  My coach was used in the early ARP evaluation process and several measurement runs were done personally by ARP designer Paul Unmack.

I don't think that having only one heater would even be a problem in hot weather, but that is conjecture on my part. A single heater is going to be slower to reach operating temp at start-up, and surely inadequate in cold weather, but I would not expect a problem on 90 F days.

In any case, it's not hard with a meter, but you do have to cut away the insulation around the heater brackets to get at them. If you carefully cut out a chunk you can tape it back into place with high temperature flue tape.
 
There are three possible reasons for a sudden halt in cooling:
1. A blockage in the tubing, usually a result of deterioration of the sodium chromate anti-corrosion chemical in the coolant
2. The temperature at the condensor (top of unit) does not get low enough to condense the ammonia gas back to a liquid. This is a heat shedding problem.
3. The boiler doesn't boil, i.e. isn't hot enough to make ammonia gas from the liquid in the boiler.  The amount of heat (btus) needed varies with ambient temperature, wind conditions, and the heat retention/loss characteristics of the particular installation.
 
Thank you Gary, you have amazing information. So glad I have you as a rescource for issues like this.

The other reason I think it is heat related is the fans were not engaging. They go on pretty much all day normally. But again, just a theory, not sure what the threshold is to engage the fans. I am really hoping its an easy fix, because a replacement is $4,000.
 
Malibu39 said:
The other reason I think it is heat related is the fans were not engaging. They go on pretty much all day normally. But again, just a theory, not sure what the threshold is to engage the fans. I am really hoping its an easy fix, because a replacement is $4,000.
Click to expand...

On the Norcold 1210 the fans turn on at 130F and off at 115F.

You won't necessarily have to buy a whole new unit as long as the doors are OK, worst case you may need a cooling unit. Don't know the price but I believe its about a third of buying the whole unit. I have a 2 year old 1210 that started acting funny and finally failed yesterday. Currently filled with blocks of ice waiting for a tech, it's actually colder than it's been the last week. Very expensive "ice box".
 
A quality new cooling unit can be had for around $1100, but that's without installation, taxes, etc.  It's a reasonable DIY job and takes maybe a day (with a helper here and there). No refrigeration experience or tools needed - just basic tools and handyman skills.

https://rvcoolingunit.com/1200LR-Norcold-Brand-New-Cooling-Unit-built-by-the-Amish-P13259.aspx
 
Thank you Gary and everyone for the help on this. It turns out I will need a new cooling unit, and 1100 isn?t too bad.

I came back to the RV yesterday and the temp was 50 after sitting all week on AC., ran air conditioner all week as well to keep it cool.  Turned it to LP and saw no difference. The boiler temp is 175, just as Gary said, on either LP or AC.

I have placed about 10 lbs of dry ice in there which got it down to 40, and running two interior fans. Like Sun2Retire said, its just an upright ice box right now. 
 
Gary RV_Wizard said:
I don't think that having only one heater would even be a problem in hot weather, but that is conjecture on my part.
Click to expand...

I'll go double check the service manual again but pretty sure I read that one heater water insufficient to boil the ammonia.

Edit - here from the manual: "One AC heater failure causes the system to operate at half the heat input required. The heat output of one heater is insufficient to generate the ammonia vapor required."

"Required" for what? Any cooling, or normal cooling? That it doesn't say.
 
Issue resolved!! It turns our the ARPV control, which adds fans for more efficiency and an emergency shut off, also has a 2 hour defrost cycle which activates every 48 hours. So when it shuts off and in this 100 degree heat, takes a while to get going, and frankly never really recovers.

I was able to override this function and its been 42-44 for the last 3 days in 105 heat. It cooled off to 95/65 of a hi / low and its down to 38 this morning.

If you have an ARPV control, go to set up mode, and cycle to ?deff? and turn it to off. Make sure you save it.
 
Malibu39 said:
I have placed about 10 lbs of dry ice in there which got it down to 40, and running two interior fans. Like Sun2Retire said, its just an upright ice box right now.
Click to expand...

Just curious, where do you go to buy dry ice?
 
"Required" for what? Any cooling, or normal cooling? That it doesn't say.
Click to expand...
Yeah, it's vague. But each of the heaters in a 1200 or 1210 is 225 watts, as large as the single heater in many smaller fridges.  The typical result of a single failed heater is insufficient cooling in some circumstances, but I've not heard of a case of "no cooling".  Cold weather is much more likely to be a problem than hot weather.
 
Rene T said:
Just curious, where do you go to buy dry ice?
Click to expand...

Our local Fred Meyer sells it. But I found it only laste about 48 hours in our frig, so not worth it. I replaced it with two ice blocks in the lower section and they are still good to go, after about 3-4 days.
 
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