My son bought a new TT two weeks ago and we went camping with him in Wyoming for a weekend. When he left his house in Salt Lake, the reefer was working fine on LP gas and electric.When we arrived at the campsite, the reefer would not cool on LP gas. We hooked up my generator and it worked fine on AC. The fine print in the Norcold manual says the unit may not work on LP above 5500 feet. We were camped at 6400 feet. Too bad we failed to research that hidden gem before he purchased the unit. All of his camping is above 5500 feet and there is no AC power available to run the refrigerator. There is a flame on the unit, but evidently, it's not hot enough to get the refrigerant up to the proper temperature.Does anyone have any suggestions? I've done some research, but can't seem to come up with an answer for him other than to purchase a generator and run it 24/7 when he's camped out. I can't find a replacement orifice which would allow for a hotter flame. I thought about having him install an inverter, but I just can't figure out if he'd have enough battery/solar charging capacity to be successful. According to the specs, the electrical heating element draws the following:300W/2.5A at 120vac resistance 48 ohms.Does anyone have experience in overcoming this problem? I've seen a few related articles on this and other forums, and most of the answers fall into the following categories:1. Mine works fine at altitude. (won't help him) 2. You should have done your research before you bought. (too late now).3. Stay in an RV park so you have power when at altitude (Won't work - Dry camps only).So if you have other suggestions, I'd sure appreciate hearing from you.

Add solar and batteries and power it with an inverter. If you are not running ac a 1000 watt Honda as back up on cloudy days will charge batteries enough for the fridge.

Another option is to swap it out with a 12V compressor unit, and add solar to keep the batteries charged.

Sound to me like you have a problem with the burner. You should see a reduction in cooling. It shouldn't quit.In addition, the 5500 feet is a guide line as to where the burner efficiency may start to fall off due to less oxygen.If it's a new TT, head back to the dealer and ask them to take a look at it. Something isn't burning quite right.

Good evening, sorry to hear about your problem. The problem is the gas jet orific is for operation at sea level. It is too large an orific for operation at 6000ft. Need to decrease size 4%/1000 ft above 2000ft. So if your jet is 39 you need a 42 or 43. The number refers to the drill bit size higher # is a smaller size. The problem at high altitude is the gas to air volume portion is screwed up due to fewer oxygen molecules per volume of air. Will send you a great reference clarifying this concept. Don't have it with me . You are in an auster environment in a remote location. This calls for thinking and improvising in your situation you can't buy yourself out of the problem. So two options. Google Norcold find out the various jet orific sizes for different models. Replace your jet with another with smaller orific. Two, pull jet solder opening closed get proper driill bit and drill new opening of appropriate size. Test it you can always increase or decrease the opening size dictated by performance in the field. Suggest you continue to google high altitude gas jet orific sizing. You will find a reference the the proper formula to calculate orific size as well as charts plotting altitude and size.

High altitude reference:manuals.therrconline.com

Norcold Refrigerator Help Needed - Won't cool at altitude

11 Replies

dougrainer
Nomad
Jul 13, 2015
TucsonJim wrote:
tchil wrote:
I would be surprised if the gas orifice actually needs to be changed. I have the original orifice in my norcold and it works fine from sea level to 10K feet. I live at 8500Ft and most of my camping is at that alt or above. Can you see or hear the flame? could be as simple as the ignitor not working properly. Is it possible that there is a piece of insulation in the flue? I would check those items first since there easy and free.

He has flame at all altitudes. It works fine below 5500 feet, and does not cool above that level. Evidently, there is not enough heat at altitude to start the absorption process. Model number is n811 which is probably different than yours.

I would still verify LP pressure at the refer. 11.5 inches W/C. Even at 11 inches it would affect performance at altitude The HIGHER the LP pressure the better it will work at hi altitude. But, without a manometer, you cannot change the LP pressure safely. NO higher than 11.5, period. Doug

OPEN the flame observation door flap to get more air to the burner. Is this thru the roof ventilated or does it have two sidewall access doors(in slide room)? NO mud nest screens or any added screen material on the outer refer doors, correct?
TucsonJim
Explorer II
Jul 13, 2015
tchil wrote:
I would be surprised if the gas orifice actually needs to be changed. I have the original orifice in my norcold and it works fine from sea level to 10K feet. I live at 8500Ft and most of my camping is at that alt or above. Can you see or hear the flame? could be as simple as the ignitor not working properly. Is it possible that there is a piece of insulation in the flue? I would check those items first since there easy and free.

He has flame at all altitudes. It works fine below 5500 feet, and does not cool above that level. Evidently, there is not enough heat at altitude to start the absorption process. Model number is n811 which is probably different than yours.
tchil
Explorer
Jul 13, 2015
I would be surprised if the gas orifice actually needs to be changed. I have the original orifice in my norcold and it works fine from sea level to 10K feet. I live at 8500Ft and most of my camping is at that alt or above. Can you see or hear the flame? could be as simple as the ignitor not working properly. Is it possible that there is a piece of insulation in the flue? I would check those items first since there easy and free.
wasatchmtnatvr
Explorer
Jul 13, 2015
Have dealer verify lp pressure at refer test port, not stove. They may have to lower to 10.25 " water column, to lean out fuel to match thinner air.
TucsonJim
Explorer II
Jul 13, 2015
Thanks folks. Since he just bought this rig two weeks ago from the dealer, he'll give them a try at it first. But I'll certainly help him with changing orifice sizes if it gets to that.

Appreciate the advice.

Jim
Old-Biscuit
Explorer III
Jul 12, 2015
Flotsam nailed it.

Norcold does not have a 'high altitude kit'...just the warning :S

Best to get several different size orifices and test at altitude for best effect.

Fridge is running fuel rich.....staving for air
Small opening orifice at 11" WC LP pressure will provide proper air/fuel ratio
Flotsam
Explorer
Jul 12, 2015
High altitude reference:

manuals.therrconline.com
Flotsam
Explorer
Jul 12, 2015
Good evening, sorry to hear about your problem. The problem is the gas jet orific is for operation at sea level. It is too large an orific for operation at 6000ft. Need to decrease size 4%/1000 ft above 2000ft. So if your jet is 39 you need a 42 or 43. The number refers to the drill bit size higher # is a smaller size. The problem at high altitude is the gas to air volume portion is screwed up due to fewer oxygen molecules per volume of air. Will send you a great reference clarifying this concept. Don't have it with me . You are in an auster environment in a remote location. This calls for thinking and improvising in your situation you can't buy yourself out of the problem. So two options. Google Norcold find out the various jet orific sizes for different models. Replace your jet with another with smaller orific. Two, pull jet solder opening closed get proper driill bit and drill new opening of appropriate size. Test it you can always increase or decrease the opening size dictated by performance in the field. Suggest you continue to google high altitude gas jet orific sizing. You will find a reference the the proper formula to calculate orific size as well as charts plotting altitude and size.
Joe417
Explorer
Jul 12, 2015
Sound to me like you have a problem with the burner. You should see a reduction in cooling. It shouldn't quit.

In addition, the 5500 feet is a guide line as to where the burner efficiency may start to fall off due to less oxygen.

If it's a new TT, head back to the dealer and ask them to take a look at it. Something isn't burning quite right.
coolmom42
Explorer II
Jul 12, 2015
Another option is to swap it out with a 12V compressor unit, and add solar to keep the batteries charged.