Dometic 3- Way Fridge

[@Michael]

Originally Posted by Doneworking

I sense on this thread and others on the B forum a reluctance on the part of many to use the gas setting on the refrig. I am curious as to why??? It obviously is more efficient than 12v or 120v and is very stingy on lp useage. Is it a concern about the flame itself and having to extinguish it before filling up with fuel or is it just a personal preference?

When I had a trailer with and absorption fridge, I ran it on propane while driving all the time. Some said that in the event of a gasoline spill, the flame from the propane fridge would cause an explosion at a gas pump. I figured that was a low probability event and left my fridge on propane when filling gasoline any time that there was airflow or a breeze around the pumps and/or I was able to position the trailer away from the pumps while fueling. Sometimes, if the pump area was constricted or crowded, I'd temporarily switch the fridge to 12v while in the constricted area.

In some tunnels, one cannot have propane. I never drove through a tunnel that had signage restricting propane, so for the few that I drove through, I left the propane on and the fridge on propane.

The only problem I had was that occasionally a crosswind would blow out the propane flame and the fridge would get warm. I got in the habit of checking the fridge each time I stopped, and resetting it if the flame had blown out.

--Mike

[peteco]

Originally Posted by jrobe

The other option is to just upgrade at some point to a modern, efficient compressor refrigerator and forget about propane, 110v and generators and never have to think about refrigeration anymore. With a decent alternator, we can make a trip to the local store and replace the battery power that the refrigerator uses in a day. I don't even have a solar panel but it wouldn't take a very big one to virtually do the same. My biggest concern is monitoring the controller adjustment so the beer doesn't freeze on 12V power.

I would like to replace my Dometic RM2554 5 cu-ft absorption fridge and upgrade to a compressor fridge, but there is not one available that I like. The 2 exact size replacements that I am aware of have generally bad reviews: Vitrifrigo DP150i and Norcold-DC558

If NovaKool made an exact size replacement I would get it.

[Doneworking]

Mike, you and I are on the same page of the song book. I live in a part of the country where we have used CNG (compressed natural gas) to run trucks and pickups for decades. The last time I observed, UPS was driving them around here. Nat gas is pretty clean, efficient and certainly not subject to foreign control of supply. LPG is much the same. Personally, I have never heard of a vehicle here having safety issues with CNG or LPG (aka propane).

To each his own

Everyone has to do what they are the most comfortable doing with their rigs. I am just not into spending thousands of bucks to goose up my 12v systems to run everything but I am fascinated with and have researched the technology and it is really cool. So is filling up my propane tank for less than a twenty dollar bill.

[eric1514]

Originally Posted by peteco

I would like to replace my Dometic RM2554 5 cu-ft absorption fridge and upgrade to a compressor fridge, but there is not one available that I like. The 2 exact size replacements that I am aware of have generally bad reviews: Vitrifrigo DP150i and Norcold-DC558

If NovaKool made an exact size replacement I would get it.

NovaKool makes a kit to perhaps convert your fridge.

Nova Kool, refrigerators, freezers, Marine, RV, Truck

[peteco]

Originally Posted by eric1514

NovaKool makes a kit to perhaps convert your fridge.

Nova Kool, refrigerators, freezers, Marine, RV, Truck

Thanks. I think by the time you go to the trouble to do this mod you might as well go to the trouble to modify the cabinet to hold a different size refrigerator.

[peteco]

Originally Posted by peteco

I would like to replace my Dometic RM2554 5 cu-ft absorption fridge and upgrade to a compressor fridge, but there is not one available that I like. The 2 exact size replacements that I am aware of have generally bad reviews: Vitrifrigo DP150i and Norcold-DC558

If NovaKool made an exact size replacement I would get it.

I had sent an email to Nova Kool recommending they make a fridge as a drop-in replacement for the RM2554 size. I did not get much of a response. So if anyone has a connection with NovaKool please tell them there is a great market for this size fridge, especially since the competitors are not that good (IMO).

[eric1514]

Originally Posted by peteco

Thanks. I think by the time you go to the trouble to do this mod you might as well go to the trouble to modify the cabinet to hold a different size refrigerator.

I guess it depends on what you're good at. I'm not much of a woodworker and I don't have the tools to do nice cabinet work but I'm pretty sure I could have that fridge out and back in two days max.

[hbn7hj]

Originally Posted by peteco

I would like to replace my Dometic RM2554 5 cu-ft absorption fridge and upgrade to a compressor fridge, but there is not one available that I like. The 2 exact size replacements that I am aware of have generally bad reviews: Vitrifrigo DP150i and Norcold-DC558

If NovaKool made an exact size replacement I would get it.

I thought the Novakool r3800 was a perfect fit being 1.5” short? There is a youtube video of someone putting one in, replacing an rm2354.

https://www.youtube.com/watch?v=RfSRsoxON_w

[hbn7hj]

Originally Posted by @Michael

When I had a trailer with and absorption fridge, I ran it on propane while driving all the time. Some said that in the event of a gasoline spill, the flame from the propane fridge would cause an explosion at a gas pump. I figured that was a low probability event and left my fridge on propane when filling gasoline any time that there was airflow or a breeze around the pumps and/or I was able to position the trailer away from the pumps while fueling. Sometimes, if the pump area was constricted or crowded, I'd temporarily switch the fridge to 12v while in the constricted area.

In some tunnels, one cannot have propane. I never drove through a tunnel that had signage restricting propane, so for the few that I drove through, I left the propane on and the fridge on propane.

The only problem I had was that occasionally a crosswind would blow out the propane flame and the fridge would get warm. I got in the habit of checking the fridge each time I stopped, and resetting it if the flame had blown out.

--Mike

This comes up every two years or so and we have learned we cannot change anyone’s mind. Roadtreks are worst case as the filler and fridge are on the same side. We just post a picture and let it go. There are many more.

[peteco]

Originally Posted by eric1514

I guess it depends on what you're good at. I'm not much of a woodworker and I don't have the tools to do nice cabinet work but I'm pretty sure I could have that fridge out and back in two days max.

The electrical system also needs upgrade: batteries, charging, wiring etc.

[peteco]

Originally Posted by eric1514

I guess it depends on what you're good at. I'm not much of a woodworker and I don't have the tools to do nice cabinet work but I'm pretty sure I could have that fridge out and back in two days max.

Originally Posted by hbn7hj

I thought the Novakool r3800 was a perfect fit being 1.5” short? There is a youtube video of someone putting one in, replacing an rm2354.

The RM2554 is taller.

42-5/8H x 23-3/4W x 24D

[hbn7hj]

Originally Posted by peteco

The RM2554 is taller.

42-5/8H x 23-3/4W x 24D

So you should be good to go. Doesn’t take any skill to make a stand for it or cover up the opening at the top. The top must be filled with insulation to force the heat out the vent.2

[eric1514]

Originally Posted by peteco

The electrical system also needs upgrade: batteries, charging, wiring etc.

I replaced the absorbtion fridge in my Travato with a Novakool R3100. I would have preferred a larger unit, but like I said, I'm no cabinet maker. The other stuff was easy.

[ChicagoTom]

I would never use the 12V. Useless and sooner or later you'll forget to turn it off, or like others who have it programmed, for some reason it often fails. Known to kill the life of a battery. JMHO It will stay about the same temp, while traveling, for about 3-4 hours, without any power or propane, so not a huge benefit to have the 12v getting beat up.
BTW, Everyone is always talking about external fans, yes they do help, but not nearly as much as a decent 3 speed rechargeable fan pointed at the upper shelf fins inside the refrigerator. I have 2, one charging and one running. Switch them out at night, in the morning and then afternoon. It runs for about 5-6 hours. If it's really hot I may switch it out an extra time. One-time Heating and A/C Tech...........living in a hot summer climate

[sg13]

Don't drive older Roadtreks with propane on. Propane line is run through the wheel well. A friend blew a tire on his 2004 RT. Started a propane fire, the RT burned up as did some of the forest!

[3fox3@att.net]

We have owned a 2007 210V with the 3-way refrigerator since 2010 and have driven it about 105,000 miles since then. In talking with other Roadtrek owners soon after we purchased ours, we decided too follow the same protocol that you do. If only driving a couple of hours between stops we may leave the propane on but typically turn it off when driving for more than an hour. We have also learned that the refrigerator works OK if not really level. We also cool out down overnight before we begin a trip and almost always have enough frozen food to nearly fill the freezer at the start. Also don't overfill the refrigerator...make sure there is enough space for good air circulation.

[rtbill]

The thing that provides the greatest benefit with absorption fridges in Roadtreks, and likely other Bs with similarly poor fridge installations, is better draft over the coils, specifically the finned coil at the top. These fridges are intended to have a tall chimney above to create natural draft. The RT installation sorta kinda follows Dometic's guidelines, but results in the fridge only sorta kinda working.

Long ago I installed a bank of computer fans to blow air over the coils. The fans are installed on the lower removable panel, and the edges around the fans are taped to prevent air escaping. On the upper panel, the two lower vents are taped closed so that all the air is forced to blow over the finned coil.

With the fans running our fridge works spectacularly well. It has coped with 100+ temperatures in the southwest. It holds temperature on DC when driving.

I measured the duty cycle of the heater over several consecutive hot summer days. On AC the duty cycle dropped from 76% with the fans off to 61% with the fans on. On DC the duty cycles were 89% with the fans off and 72% with the fans on.

The fans draw about 200 mA, which is well worthwhile compared to the fridge's consumption.

[engnrsrule]

Originally Posted by Doneworking

I sense on this thread and others on the B forum a reluctance on the part of many to use the gas setting on the refrig. I am curious as to why??? It obviously is more efficient than 12v or 120v and is very stingy on lp useage. Is it a concern about the flame itself and having to extinguish it before filling up with fuel or is it just a personal preference?

The reluctance has to do with some State rules that say propane tank valves must be closed when rolling, not just about gas stations. I absolutely prefer propane unless 110 is available.

[avanti]

Originally Posted by engnrsrule

The reluctance has to do with some State rules that say propane tank valves must be closed when rolling, not just about gas stations.

I have never heard of this. Can you post a link to an example?

[engnrsrule]

Originally Posted by avanti

I have never heard of this. Can you post a link to an example?

I guess I am a victim of urban legends. There are a lot of "opinions" but only a few places that have laws or regs. Propane must be turned off on Chesapeake Bay Bridge and Hampton Roads Tunnel, and on the ferries in Washington State. Propane equipped vehicles are prohibited in the Baltimore Tunnels and lower level of the George Washington Bridge. RV designed GPS devices cite propane restrictions based on your routing, but are not always clear.

Accidents at service stations are real. I read of one instance where a propane fire followed a rear tire blowout where the tire debris severed a propane line.

So as a retired Safety Engineer, I am going to stick with my protocol and turn it off at the tank when rolling.