2008 RoadTrek 210P Domenic 'fridge cooling?

[Kegan]

Frustrated with my 'fridge. I believe it is a five cubic ft model. A few questions for folks with similar set ups -

1. How long to allow an empty 'fridge to get to temp?

2. Does loading the fridge up completely help or hurt keeping things cold? I assumed that once cold, more cold stuff would put less, not more, strain on the cooling unit.

3. I'm getting a temp of approx. 43 degree (F) in an empty 'fridge, allowing many hours to cool prior. Is 43 degrees about right for an RV unit?

I purchased this unit recently and am enjoying it quite a bit, but it does seem to have a gremlin or two to work around.

[hbn7hj]

Looks normal to me. It takes a day to bring an absorption fridge to temp but considering it is winter yours could be a bit weak.

A full fridge adds a bit of thermal inertia.

To improve this you need an improved electrical system and a compressor fridge. There are many threads here on this. Also threads about helping the performance of your present unit. Your wallet probably just jumped so welcome to our world.

[Doneworking]

Kegan, we have a 2007 RT 210P and probably the same 5 cubic foot refrig you have on your RT.

You will find lots of posts about Class Bs and refrigs on this and other forums. Here are a couple of things I always do. We have owned our RT since it was new.

1. Putting in cold stuff prior to cooling down the refrig should be of great benefit.

2. In order, these refrigs work best on gas, then 120v, then 12v DC. We only use the 120 V AC to cool down when it is in the garage because we obviously don't want to run it on LPG in an enclosed space. If it is outside, it is always on gas even if we are camped somewhere with hookups. The 12v DC setting will run down your batteries quickly if the engine is not running and going down the road.

Going down the road, we run on 12V DC and that way we don't EVER forget to turn off the propane setting when we are buying fuel for the Chevy.

We have been very lucky, I guess. Since 2007 we have never had a problem with our refrigerator. You will see lots of posts and recommendations about compressor fridges and they are really nice, but they cost a lot and if you boondock as we mostly do, you will use a lot of your coach battery juice. I bet compressor vs conventional rv frigs have been discussed umpteen jillion times on the forums. All I can add is our original refrig works great for us and we live in Oklahoma which has really hot summers.

I wish we had some "hot summers" days now for a few days. It was 5 below in OKC this morning and this cold weather is popping records from Kansas to Mexico. Maybe north of here also, but I have concentrated on the SW because of the resultant infrastructure problems. Our homes in particular are just not built for sustained extreme cold.

[mangomike]

Hi
I have a 2008 210p , so here is my usage and tricks.
I've got LOTS of food handling experance .. 40 years in the restaurant biz.
I'm going to answer your 3rd Q first
According to the USDA food temp should never go above 41 dreeges for more then 2 hrs. I use the 41 Dg as a referance temperature .
Your Q 1 ,,,, We run our frigr over night (on LP) before loading it for a trip, It will get down to 30 - 35 Dg in Florida summer or winter .. . If we are going for just a day or two we use a cooler.
These 3 way friges are not the best at cooling ,,,,as mentioned a compresser frige is MUCH better at cooling . But, a compresser frige will not run on LP and our battery bank will not run one for long.
Q,,, 2.... The more "cold" stuff you put into your frige the better. The food will act as a cold mass and help to keep things cold. When starting a trip we will try to srart out with a well frozen meal( think Chili) of some kind. This acts like a block of ice in the frige and the meal will thaw out in 2 or 3 days and be ready to eat .
Some other trick to help the frige out
>>>>you can install a fan in the outside rear of your frige compartment This will help disapate the heat that your cooling unit is making.
>>>>you can put a circulating fan in you frig .. this will help distribute the cold air <<<< I have never had much luck with the battery units... some folks hard wire them in.
I'm sure there are some other little tricks .. more insulation around the frige would help,but I have not read about anyone doing that ????
You should keep a frege thermometer in the frige for referance ,,, some folks use a wifi one so that you don't need to open the frige to see the temp.
And of course don't have the door open any longer then necessary .
We starting RVing coming from Sailboat cruising ,so we were use to conserving the frige ,water, electricy, ect. On the other hand if you plug in every night conservation is not as important. We Booncock a lot
Take care and enjoy your RV....
Michael

[Doneworking]

Take a look at these. We use similar.

https://www.campingworld.com/fridgec...E&gclsrc=aw.ds

Also, an inexpensive indoor/outdoor wireless thermometer is great because you don't have to open the door to check the temp

We have the indoor side velcrowed to the dash in front of the shotgun seat. My wife likes the reassurance of knowing all is well as we go down the road.

[mkguitar]

Originally Posted by Kegan

Frustrated with my 'fridge.

we all are!


but a compressor fridge conversion with an electrical system to run it will quickly be thousands of dollars


the manuals are generally available online, google your model number



the tips and advice posted are inline with my experience, managing energy use in a B and tending the fridge are my new pastimes

I know that I can get the fridge to about 75º~80º below ambient temperatures

I have fans on the fins, a small internal fan to move cool air inside the fridge.
when super hot I put freezer packs in the freezer an rotate them to the fridge section- this helps on a long drive on DC

know a hot rv robs cold from the fridge

park fridge side in the shade

get it level within a few degrees


many rvs have the fridge on the fuel filler side- ...they tried running on propane and forgot



mike

[Want a B]

Originally Posted by mkguitar

... but a compressor fridge conversion with an electrical system to run it will quickly be thousands of dollars...

mike

I paid under $1,100.

[engnrsrule]

Look up my recent post on replacing my Dometic with a newer model. Summary: performance was declining and unreliable (14 years old); we wanted to retain propane option for boondocking; newer dometic model exact fit to space; some nice features in the RM8505 like removable freezer compartment to make space all fridge, adjusting latch to prop door open when not in use, alarm when door left open, automatic switching between 110v, 12v and gas.

[Polo]

Kegan,

Our first experience with an absorptive type fridge was with our 99 Winnebago Rialta... It took us a while to get used to it but after that we have become big fans of these types of fridges because of their flexibility.

Some others have mentioned their opinions/techniques but things we do to "manage the cold" follow:

1. We pre-cool the fridge before departure.... usually overnight but 4-5 hours is sufficient.
2. When we load the fridge we put some icecubes and some "blue ice" packs in both the freezer and fresh food compartment. These help the fridge get to and maintain operating temps more easily.
3. We plan minimal opening of the fridge, especially when underway... To wit, we carry cold drinks in a small cooler in the cab.
4. Like others we have a circulating fan in the fridge section which also serves to help keep the cooling vanes defrosted. We also have a fan in the back of the fridge cabinet which moves warm air out of the boiler area while pulling cool outside air in.
5. A lesson from our home chest freezer... a fuller compartment takes on less warm air when opened.
6. Our current Norcold 611 does not have a 12v option (only good to maintain temp going down road anyway) so if we cannot or do not want to run on LP while underway we put a few "blue ice" blocks in the fridge section to help keep it cool. It's amazing how well insulated these fridges are if the seals are good and they are not often opened.

One of the things we like about the absorptive fridge is its simplicity (no moving parts... so also quiet) in addition to its dual fuel capability. We are travelers so are not always plugged into shore power overnight. It's nice to be able to run the fridge on propane to keep things cold when electricity is not available.

Our fridge is 15 years old and worked pretty well but was persnickety to start on LP sometimes. We found the burner orifice had some rust... I tried to replace it but could not break the old one loose even with penetrating oil and two wrenches. Eventually after banging on it some (a lot of rust fell out), it would light reliably. But since we live in a humid environment near the Gulf of Mexico I knew rust would be a continuing issue.

We considered replacing the fridge but the cost was astounding regardless of whether an absorptive model or compressor-based one. In the end we decided to have the fridge overhauled by JC Refrigeration in Indiana while were in NW OH visiting my brother. They installed their renowned boiler/cooling system and evacuation fan along with my new burner orifice in a couple of hours. I also bought a dual-zone remote reading thermometer with user selectable alarms from them. It normally stays magnetically attached to the range hood but we can bring it up to the cab if we want to monitor things more often/closely. After the JC Refrigeration "Amish" mod, our fridge is incredibly more effective/efficient. I normally ran it on the middle setting of "3" (1-5) but it was too cold so I had to back it off to "1". The fridge now runs at 38-40F and the freezer 10-18F under most conditions. BTW, everything I have read says these fridges can only cool to about 45-50F below ambient air temp so best to have inside of coach coolish and park in the shade.

On a related note, for those with absorptive fridges there is a great safety device called an ARP Fridge Defend which can protect your boiler from overheating extend the life of the boiler/cooling stack. It's not terribly expensive and we installed one for peace of mind.

Happy Trails in 2021!

Paul and Christine
NW FL, USA

[rtbill]

Improving the performance of an absorption fridge in a Roadtrek is easy because the factory installation is so poor. In bigger RVs the fridge has a proper chimney above to induce a draft over the coils. That's missing in Roadtreks.

The fridge needs a fan to blow air over the coils. There are aftermarket kits. On our 200 I installed computer fans in the lower cover. A key point is to force the air over the finned tube at the top. I taped closed the two lower vents in the upper vent panel so all the air exits from the top vent, thereby passing over the finned tube.

With the fans on our fridge chills down in a couple of hours. It stays cold running on 12V when driving. It also uses less power with the fans. I measured the duty cycle on both 12V and 120V.

[Infohound]

Originally Posted by Want a B

I paid under $1,100.

Could you tell me about your $1100 conversion? What type of and how many batteries? Any extra items needed? Does it have a separate inverter? Any other info that you can provide? Thanks.

[engnrsrule]

Infohound and Want a B, much depends on what your starting point is and how much space can be repurposed to electrical capacity. My sprinter has one battery compartment which can hold a large 12v with room to spare, or two 6v golf cart batteries which give me more than twice the ampere hours. My fridge upgrade was exact same size and foot print dometic. While the dometic 3 way was not cheap, going to a compressor fridge would have necessitated inverter cost and wiring changes, as well as cabinetry work. When I upgraded my inverter from the 750 watt Tripplite, using the space I had available I was constrained to1500/3000w pure sine wave. More than that would have cost me in storage space. Plus I do like having propane and 12v options.

[Want a B]

Originally Posted by Infohound

Could you tell me about your $1100 conversion? What type of and how many batteries? Any extra items needed? Does it have a separate inverter? Any other info that you can provide? Thanks.

2008 Born Free, Built for Two.

Dometic Model RM 3762. 120 VAC or LP.

Conversion done by: JC Refrigeration, Shipshewana, Indiana.

Two lead acid Marine Master Deep Cycle DC27 batteries rated at MCA 705 and CCA 575 each. Age of batteries unknown, came with the coach when I bought it used.

I'm not sure about "extra items". Everything was done and provided by JC.

Yes the conversion has a small separate inverter. 12 VDC to 120 AC.

JC removed the Dometic from the cabinet, gutted the absorption stuff, installed the compressor stuff, reused the existing wiring and reinstalled the Dometic back into the cabinet. The Dometic's control board and on/off display were reused. Conversion will automatically turn off if voltage drops below a preset level. Conversion also included a continuously running interior fan to even the coldness (manual on/off switch).

Following information is from my coach's Victron BMV-712 battery monitor.

Batteries were at 100% full charge and Dometic precooled to 40 degrees. 3 Watts when the compressor was not running and 101 Watts with the compressor running. Interior fan on. 3 hours later the batteries were at 89% charge. Victron indicate 7 hours and 3 minutes (compressor running) left on the batteries (with 50% of batteries remaining).

11% discharge in 3 three hours. Let's make that 12% which would equal 4% per hour or 25 hours before my batteries reach 50% discharge.

Another test is when we left the Coach in the Ark Encounter parking lot for four hours with Dometic runnig on batteries. On our return the Dometic display showed 40 degrees (as it should) and our food was still cold. I forgot to check the Victron for additional information.

Hope this is what you were asking for.

[Want a B]

Reference my post #13 above.

Question about a separate Inverter got me curious. I opened the exterior lower refer vent where during the conversion they installed the "separate Inverter". I traced the wiring.

12 VDV power from the Born Free's fuse panel. 120 VAC to the Dometic's control board. A $20 part on Amazon. The rest of the conversion runs on 12 VDC.

Here is a picture (and specs) of the "extra Inverter":

http://www.wolffsrowdyrangers.com/RV-Inverter.JPG