Orifice drilling (1 Viewer)

[baja1d]

Long story short... Bought a fancy Norcold N300R refrigerator from a guy off of CL only to find out that it doesn't work on propane above 5,500'. Norcold doesn't sell a "high altitude kit" and their customer service is seriously lacking!!! Their recommendation is to run the refrigerator on 110v a/c at elevations above 5,500'. Unfortunately, I live at 5,280' (Denver) and all my camping is up into the Rockies, the more remote the better and certainly without a/c. At any rate, I originally adjusted the gas psi higher then realized that I'm going the wrong direction... There's less O2 up here. Tried turning the gas back down but no bueno. My next step is to solder the orifice closed and re-drill a smaller opening. From internet searching it sounds like you need to drop 1 drill bit number for every 2000' of elevation gain. Norcold will not give up any info regarding BTU’s or initial elevation setting but I’m guessing they set it at 2,750; dead nutz in the middle of 0-5,500’. Based on my shade tree knowledge, I'm thinking that ultimately I'll end up two, maybe 3, drill bit sizes less than where I'm at right now for 8,800'. Does this seem plausible?

 

[baja1d]

BTW, I've cleaned the orifice, blown out the chimney flue, and even turned the frig upside down for 24hrs to remix the ammonia solution. The thing works great on a/c but will not even maintain a temperature on propane.

 

[titanpat57]

Ask around at a HVAC supply house, and see if they can recommend a top notch trouble shooting guy that is probably very familiar with the obstacles related to high altitude appliances. He may be able to get you working, although maybe it wont work below that level... I mean it is a pretty simple system.














Either that or move to Florida...

Good luck

 

[Rubiconcruiser]

Is the propane valve and igniter actually for propane?

 

[baja1d]

Ask around at a HVAC supply house, and see if they can recommend a top notch trouble shooting guy that is probably very familiar with the obstacles related to high altitude appliances. He may be able to get you working, although maybe it wont work below that level... I mean it is a pretty simple system.

Either that or move to Florida...

Good luck

Found a guy & I'll be dropping it off next week. I did set the water column psi but still can't get it to cool down below 60. It is definitely a propane set up bit I would never recommend a Norcold

 

[John E Davies]

If I were going to all the trouble to re-work an appliance for high altitude use, I would be sure to make it easily reversable and "tunable".

Can you silver solder a threaded socket so you can screw in different jets? Just like a carburetor..... Depending on your present hole size you might even find existing brass jets in the size range you need, for an older motorcycle or lawn mower maybe.

Just a thought.

John Davies
Spokane WA USA

 

[baja1d]

If I were going to all the trouble to re-work an appliance for high altitude use, I would be sure to make it easily reversable and "tunable".

Can you silver solder a threaded socket so you can screw in different jets? Just like a carburetor..... Depending on your present hole size you might even find existing brass jets in the size range you need, for an older motorcycle or lawn mower maybe.

Just a thought.

John Davies
Spokane WA USA

I like it. I've spent way too much time on this very nice POS and should just scrap it! It appears that the entire issue may be totally unrelated the the orifice. Rather, it maybe the thermostat. Either way, gotta let a pro look at...

 

[sggoat]

I'm a newbie here when it comes to refrigeration, but I don't understand why a totally closed system would be affected by anything outside of it, be it altitude/sand/dust/rain/etc. As far as I know, the only external thing that can affect the cooling capabilities of a refrigeration system are the outside temp/humidity(what the system is exhausting into)--Maybe higher altitude's thinner air won't exchange as well??--does this make any sense?

 

[John E Davies]

I'm a newbie here when it comes to refrigeration, but I don't understand why a totally closed system would be affected by anything outside of it, be it altitude/sand/dust/rain/etc. As far as I know, the only external thing that can affect the cooling capabilities of a refrigeration system are the outside temp/humidity(what the system is exhausting into)--Maybe higher altitude's thinner air won't exchange as well??--does this make any sense?

It's not totally closed. Maybe you should read up on how an absorption refrigerator works - it has some very different parts and chemicals compared to the compressor type fridge in your kitchen....

http://www.ehow.com/how-does_4572503_propane-refrigerator-work.html

The problem the OP is having (perhaps) is that the burner is running too rich at high altitude. It's a common problem with any gas appliance when the O2 content gets too low.

John Davies
Spokane WA USA

 

[Mace]

Propane will still burn in absolute stupid rich mixtures..

I've had my dometic fridge in my camper way about 6K and it works great.

What's the flame look like when running off of propane?

 

[baja1d]

Boy do I wish my Domestic right now! Flame looks great. Borrowed a water column gauge & double checked the regulator psi- okay there. I'm beginning to think that this isn't an orifice issue at all but rather a thermostat issue.

Here's the latest... Still works as it should on electricity but will only cool to 50-60 degrees on propane. Additionally, it will heat up to 50-60 if it was started on 110 & then switched over to propane.

I've installed two 12v computer fans to cool the coils, flipped the fridge over for 24 hours to re-mix the refrigerant, and cleaned/blown out the exhaust vent. I even tried moving/adjusting the thermostat position across the interior fins w/o any changes.

However, while moving the regulator tubing on the fins I happen to look at the gas indicator & noticed that each time I'd grab the tubing the flame would go from pilot to free burning/ cooling. From what I've read online, there a chemical solution inside of that tubing that tells the regulator to open the gas valve. At any rate, I give up & I'm taking it into a tech tomorrow. I'll post the results.

 

[Coastline]

I just found this thread. I have seen a lot of Norcold and Dometic products over the years and my two cents worth says that, for the size of the unit I recommend that you sell it and invest in a Dometic 12/120 volt freezer refrigerator. Norcold sells them also, but I won't use them in my trailers. An aside the replacing what you have with a 12 volt unit is the expense of LPG. Look into a ZAMP Solar system and a battery bank to power the fridge, and many other devices.

 

[baja1d]

I've often thought about solar. My grandparents have a house in Mexico that's run off the sun. However, I'd take me 25 years to break even on a $1,500 ZAMP system for this particular love shack. The next camper maybe a different story...

 

[se2000]

Did you see if they had a NG orifice? They are smaller so may get you closer. Could be multiple issues. You could always take a road trip down the hill to see if it works at say 3000'.
Taking it to a pro was a wise choice. Modifying gas appliances used indoors should always be done by a pro. Saying that, I did convert my home appliances to run LP as they were previously on NG. But it was simply replacing factory parts with factory parts.