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Inverter Runs Gas Absorption Cooling Unit

Reply #1 –
Yahoo Message Number: 83394
Hi,

Back in June I had done some fiddling around with running my Norcold 1200LRIM off my inverter. Several folks had emailed me and requested more details on this project. I finally got an article completed. The link is
here:

http://www.muniac.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=148#Post148 Enjoy and safe travels.

Best - Scott

2006 Allure 430 40' #31349

(Bus-Stead Lemon) My Allure Page http://www.muniac.com/Allure%20Page.html

Re: Inverter Runs Gas Absorption Cooling Unit

Reply #2 –
Yahoo Message Number: 83395
Very informative. Thanks for sharing your implementation. Nicely done.

Jim

99 Magna #5629

Re: Inverter Runs Gas Absorption Cooling Unit

Reply #3 –
Yahoo Message Number: 83397
Scott, you said that it's not a good idea to run the frig using propane, so what are we supposed to do. I'm going to have a Samsung installed in 2-3 months. We're headed out on our very first trip in a couple of weeks. We're going to Fla for the winter.
I've read that folks have been using these systems for years and not having problems, just as long as you do an inspection to make sure everything is operating properly.
The unit in our coach has not been used very much, but I don't know if that accounts for much. Let me know your thoughts.
By the way, great article. John 2003 Allure 30951

Re: Inverter Runs Gas Absorption Cooling Unit

Reply #4 –
Yahoo Message Number: 83400
Jim - Thanks. I also think the circuit has some value for those converted to domestic refrigerators. Based on what people have indicated for power requirements, I think an inverter would handle it without problems. We clam up in a week or so and head off to our next destination. I'll be running the frig on inverter power during the trip and will report back with findings.

At 11:43 PM 10/23/2012, you wrote:

Re: Inverter Runs Gas Absorption Cooling Unit

Reply #5 –
Yahoo Message Number: 83402
John - Thanks for the kind words. I just document my thoughts, concerns and impressions and offer an occasional solution for consideration. The "refrigerator on propane while traveling" discussion came up a while ago and many folks do it without problems. I'm just not comfortable with it per what I discussed in the article. My "soft" suggestion is don't do it but each to his own as they say.
On GACUs I'm not clear on how a usage cycle (ratio of time on to time off) affects some of the problems we've all been discussing. One might conclude that not using it might extend out when problems occur. A few folks I've broached the subject with say these cooling units crap out in 5-7 years regardless of the on/off time ratio. I can't confirm this, however. Whether one uses mostly the heaters or propane might also affect service life. Relative humidity and/or the presence of salt could also affect service life. Those near the ocean might see much more corrosion on steel, for example. Some of these aren't "ON" only degrading factors.
The combustion of propane in air produces moisture as a byproduct. We all know this from moving a glass pot of cool water onto the propane stove. I have questions about the rusting affects of this over time with flue gases. In particular, how it affects the boiler parts in our GACUs. As of late, I don't have any facts but just some concerns. Here's a shot of my GACU through the exterior access cover: http://muniac.smugmug.com/Maintenance/Bus-Repairs/i-9LCx4n5/0/L/IMG3637-L.jpg What I'd like to see is a small door into the sheet metal to access the insulation around the boiler. Down in the flame and cartridge heater area would do it I think. This would allow an easy inspection of the piping to track rust and other deterioration. The Norcold OEM insulation sleeve offers no opportunity for easy inspection. As for GACUs, if there are any doubts about integrity, turn it off. The proactive approach would be to replace the GACU with a after market one or install a domestic refrigerator. The stakes are just too high to play around with this if any uncertainly exists. My 5 Lbs of ham in a 2 Lb bag so to speak.
Best wishes to you on your maiden voyage to Florida. All of us want these trips and stays to go smoothly, safely and be free from aggravation/repairs. I try to document and head off known issues so things can be addressed ahead of time. I'd like to think that increases the chances for trouble free travels. Beyond just knowing your vehicle, staying in touch with the equipment is HUGE. Today Mr. Fix It gets to replace coolant bleed hoses as my proactive measure. It should be a fun time.

At 05:34 AM 10/24/2012, you wrote:

Re: Inverter Runs Gas Absorption Cooling Unit

Reply #6 –
Yahoo Message Number: 83405
John, I think the takeaway from Scott's writeup is that you have 3 options for operating the refrigerator while on the road.

1) Run it on propane (That's what I do right now)
2) Run the generator
3) Make the modifications that he described to run on the inverter.

GL on your trip.
Jim

99 Magna #5629

Re: Inverter Runs Gas Absorption Cooling Unit

Reply #7 –
Yahoo Message Number: 83406
Jim

There is a fourth option.

If your refrigerator is already cold, and you leave it closed, it will stay cold for several hours with the cooling unit turned off.
So if you travel less than four hours a day, between stops you can do so with the propane turned off.

Bob Wexler
SOB

Re: Inverter Runs Gas Absorption Cooling Unit

Reply #8 –
Yahoo Message Number: 83415
Scott

I just read your info on running the Norcold off inverter.
I ran my Dometic off my MS 2812 inverter for about 8 months, until I replaced it with a GE 18 cu ft.
My solution was much simpler.

I was able to replace a full width breaker with a double (2 half width) breakers on the inverter side. I now have a dedicated 20 amp breaker to the refrigerator outlet.
When I chose to run the Dometic on propane I simply pushed the button on the control panel to make it happen.
The only wiring was to move the hot wire from one breaker to another.
I had already installed a 200 amp alternator and the Magnum MS2812 as well as 6 Lifeline GC batteries.
My GE draws between 100 and 200 watts based on a kill a watt meter, a fraction of your Norcold draw.
I have done some Walmart and Quartzsite boondocking, but no long term since the mods.
Every thing works great and my generator recharges everything with 6-8 hours run time centered around meal prep and evening TV.

Bob Wexler
SOB
 

Re: Inverter Runs Gas Absorption Cooling Unit

Reply #9 –
Yahoo Message Number: 83417
Bob - My inverter sub-panel is maxed out. Picture of it is in the article. I can't squeeze in another circuit so my options are limited to sharing a circuit. In other words, all my breakers are 1/2 width already. If you have the option you speak of available, then it's certainly easier. As for the power draw. The Norcold heaters max out at 450 watts but they don't run full throttle all the time.
I've been trying to collect data and pictures on residential conversions with marginal success. I may go ahead and rough out an article and let people jump in with input. The goal is to accurately document all the parameters so people can evaluate what's best for them. Pluses and minuses exist for both courses of action. I've been very happy with the Pines RV after market replacement. $1k and it's done. And for those that can't add breaker capacity, the inverter switch mode relay works well too for traveling. Not the best system, perhaps, but a cost effective one that delivers good performance with simple modifications. Thanks for your input.

At 02:43 PM 10/24/2012, you wrote: