GaryMBlythe

Inverter Circuit Retrofit For Residential Refrigerator

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I am doing the Norcold 1210 to Samsung residential refrigerator conversion, and so far all is going well, but I need input from others.

My existing Norcold did not appear to be wired to the inverter, as we always got an alarm when disconnecting from shore power while running the Norcold on 120VAC. When we convert to the Samsung RF-18HFEN, the replacement for the RF-197, I would like to have the option of running it off of the inverter when not on shore power or running the gen-set. We have a 2000 W Magnum MSW inverter in our 2007 Newmar Kountry Star, and four new 6V house batteries. I am comfortable doing 120V and 240VAC wiring jobs (e.g., I ran a 30-A circuit to partially power my coach in my driveway, and hard-wired a Progressive Industries 50-A EMS on my shore power input), but I am not familiar with doing inverter circuit retrofits in an RV.

Can someone advise me what this involves and whether this is a reasonable do-it-yourself project for an experienced amateur electrician?

Thanks.

Gary

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I believe on one conversion I read that that person swap the wiring for inverter from front outlet to fridge wiring. I believe it was a Monaco coach. Otherwise you will have to add an inverter. I see if I can find it.

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wolfe10   

Only issue is how close to the refrigerator you already have an inverter-powered outlet. And, is there enough "reserve" (i.e. you don't run a lot of other high amp items on that circuit) to be able to install an additional outlet from the existing inverter-powered outlet.

Your inverter/charger already has a "pass through" feature so that when it sees shore power or generator, it automatically passes that source through to all outlets the inverter/charger supplies.

If no inverter/charger powered outlets in the area, worse case is run a new feed from the inverter output/subpanel.

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OK, thanks all. There is a breaker panel for a number of 120V circuits on a bathroom wall, the other side of which forms one side of the refrigerator cabinet, so it sounds like if I have a circuit in that panel that gets a pass-through from the inverter I might be able to feed from that. I'll just need to check wire and breaker sizes to make sure I don't overload anything.

Thanks,

Gary

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wolfe10   

**Assume you are safe working around 120 VAC**

Yup, should be easy to determine. Unplug from shore power, generator off. Turn inverter on.

With a voltmeter, check for 120 VAC between breakers in that sub-panel and the neutral and/or ground lugs in the sub panel.

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In our 2002 Monaco Dynasty we have both a 120 shore power outlet and an inverter outlet.

I have not checked them to see if when 120 volts from shore power is on that the inverter is off, but 120 at the inverter outlet when shore power is off.

Herman

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Good news is the Samsung that you chose is only 3.9 amp maximum draw, which means that it can be run on an existing circuit pretty comfortably. The bathroom circuit should be gfci, and downstream on the gfci circuit sometimes is not a good idea for a refrigerator, as the capacitor start motor on the compressor often causes enough delay that the gfci will trip, not from overcurrent, but from the delay caused by the capacitor. If using the bathroom circuit, be sure to wire in before the gfci outlets.

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kingfr   

If your existing Norcold 1210 had an icemaker then there may be an inverter circuit already there. The ice maker on the 1210 that came in our previous 08 Tiffin Phaeton was on the inverter because it needed 115V to work. There were 2 plugs in the circuit box behind the refer, one on the inverter and one not. The reason is that the 1210 needs a lot of power when on electric and will run your batteries down quickly when on inverter. The icemaker requires very little power. The inverter circuit allows the icemaker to work when you are dry camping. You are cooling with propane when dry camping which uses just a little 12V to ignite the burner.

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I believe Frank may be right about that but a sure way to test is to unplug from shore power and plug in a 120v lamp. If not try pressing the inverter button in the hall on the control panel and see if that works. You should also see the control panel of your microwave come on at the same time.

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My coach has two 120 Volt AC outlets in the 1210 compartment. The lower outlet runs off shore power and does the 1210 Norcold. The higher outlet is powered from the inverter/ shore power and it runs the ice maker. I believe this will be the same setup in your coach. Of course plugging in a light should show you exactly what you have.

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wajames   

Agree with Frank and Jack - our 04 Monaco product had 2 outlets for the 1210. Figure out which is on Inverter.

One thing to check is if the Samsung is okay on a MSW inverter.

We did the change out to a Whirlpool and it was okay for a while but the Defrost Cycle Control circuit board lets the blue smoke out on MSW. Maybe some on here can confirm or deny. We are looking for a deal on a Pure Sine

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A couple more thoughts. I would make sure the inverter is a pure sine wave. Although some are reporting that they will run on modified sine wave, at some point they may fail. I think you should have 6 high amp golf cart batteries or plan to run gen every day. Solar would be a good fit as a power source.

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lenp   

I installed a Samsung 197 last spring. Samsung advised me NOT to run it on a MSW inverter. Thus, I installed a new (dedicated) 2000 watt Pure Sine inverter.

I would certainly talk to Samsung before running it on a MSW. Might run for a while but for how long?

For info, I have three Trojan T1275 12 volt batteries for 450 amphours (would like more but no room), 750 watts of solar, Pentametric battery monitor and a TriStar MPPT-60 charge controller. The frig running all night drops the battery bank by about 15%.

Lenp

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The Samsung units are well known for being able to run on MSW and has been being used in Tiffin coaches by many owners for many years. My GE Profile also ran for over 10 years on a MSW before I switched over to a TSW and it's been running great since 1999.

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I have run my Samsung fridge for three and a half years on msw inverter, runs every time I take a trip and works well. I use a 3000 watt msw inverter to power everything in the coach except air conditioners.

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Thanks to all that have posted. This has given me good direction for how to proceed. Unfortunately I work full time and our coach is parked at a weekend property 50 miles away, so it will be this weekend before I have an opportunity to follow any of these leads. If I come up with a good solution I will post back to the forum in case there are any other Newmar owners in a similar circumstance.

I do have a couple of thoughts, though. One, it would be great if Newmar had wired the icemaker to an inverter feed, but I don't think that is the case. The icemaker and refrigerator were plugged into a single duplex outlet, and there is only one romex feeding that outlet.

However, it occurs to me that the Suburban propane heater is installed below the refrigerator, and although we never run the propane (in our mild Texas winters we run the heat pumps on park power) I expect that it has an inverter feed for the fan and igniter. I will check to make sure that is fed from the inverter, and if so, consider splicing into or robbing that circuit to power the Samsung, and possibly running the Suburban on the original refrigerator circuit.

However, the posts on MSW versus PSW inverter power have me a bit concerned. About half of the posts say "no problem" while the others say "expect problems". There is a lot of internet traffic that attests to the RF-197 being good on MSW power, but I also read that the RF18HFEN has a different compressor system. I have posed this question on a Home Depot on line product Q&A forum, but I don't have much confidence I will get a meaningful answer. Any more user input on this subject in this forum would be welcome.

Thanks,

Gary

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lenp   

I also heard from many that the 197 was fine on a MSW but after talking with Samsung I decided to go with a pure sine.

Additionally, on my coach there was only one outlet in the frig compartment and it WAS NOT powered by the inverter. No ice when on inverter! I had to wire a second outlet for the new inverter.

Lenp

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Just a quick update. Thanks to all of you who posted who gave me enough insight to proceed. I spent most of my spare time over the weekend on cabinetry for the Samsung install, but I did spend a little time investigating the inverter power.

It looks like Newmar made the inverter power retrofit relatively easy for me. All of the coach 120V power comes into a main 50A panel in the bathroom, and a 30A breaker in that panel sends 120V to the inverter through 10-gauge Romex for the pass-through. A 10-gauge Romex brings 30A back from the inverter to a sub-panel which is next to the main panel. All of the inverter circuits are fed out of that sub-panel. Currently, my refer circuit comes out of the main panel (non-inverter) but I think I can just move that Romex over to the subpanel that is fed off of the inverter and swap it for a non-essential (for my purposes) circuit that I will move to the main panel.

The only hitch might be swapping the Romex feeds from one side to the other; I either need to make them reach or I need to try to switch them from one hole in the ceiling to the other (one above each panel). If all else fails I can do a splice in each panel with wire nuts and send a short Romex from one panel to the other.

Now I just need to resolve the MSW vs. PSW issue. If I go with PSW power my $1000 Samsung residential refrigerator conversion just got a lot more expensive!

Thanks again,

Gary

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All you need to do is add a small PSW inverter 800 watt or so and keep your inverter/charger you already have to do the charging and other duties. They should be available for $200 to $300.

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I have run my Samsung on a Xantrex MSW inverter for over a year. Why not try it. Worse case is in a few years the compressor goes bad. The expense to replace that should be a lot less than the price of a TSW inverter. I bet you will not have a problem. I am using one 8D 12 volt battery. I replaced the 4 six volt batteries 2 years ago. I have run on the inverter over night. Other than a couple of LED night lights, the refrigerator and my CPAP machine were the only loads. Also, I have stayed over night in some Walmarts without the inverter on. Night time temp in the low 60's. The refrigerator temp went up 4 degrees from 38 to 42. You will find that unless you boondock for more than 1 night, you will not have any problems.

My microwave was on the second inverter circuit and the wire was routed behind the refrigerator. I installed a 2 pole double throw switch in the cabinet above the microwave that will cross over the inverter circuit to the refrigerator or to the microwave. When either is on the inverter the other is on shore power. My default position is for the refrigerator to be on the inverter. Should I need the microwave to fix lunch while traveling, I just place the microwave on the inverter and when done switch back to the refrigerator. I found the switch at Home Depot. Don't remember the price, but less than $20.00.

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boguslaw   

I am in the process of doing this exact conversion. I had a dedicated 120v feed from the panel which will need to be moved to the inverter circuit but I was advised by someone who already did the conversion to also move the ground and neutral wires over, not just the hot wire. It sounds like you were already planning that because you said Romex, which is all three conductors.

Someone wrote a nice write up on the Samsung Digital Inverter Compressor on IRV2.com. Sounds like we are all set with the MSW inverters.

Jim Boguslaw

2007 Country Coach Tribute

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wolfe10   

Yes, moving the HOT and NEUTRAL is critical. Ground really makes no difference, as main panel and sub-panels are all grounded together. So, if you like, move the ground as well, or leave it where it is.

Said another way, all the panel grounds are tied together.

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