Refrigerator upgrade question

TJLee089

2013 Itasca Reyo 25R
Are you suggesting a compressor fridge does not need to have air exchange with the coach air?
That is the part I am doubting.

You must never seal off the vents of a propane unit, since there are combustion products that have to be vented. It is just fine with a compressor fridge.
 

avanti

2014 GWV Legend 3500 I4
Are you suggesting a compressor fridge does not need to have air exchange with the coach air?
That is the part I am doubting.
Sorry, I misread your post. Yes, of course you need to vent somewhere. I though we were talking about sealing the OUTSIDE vents when upgrading from absorption to compressor. Sorry for the misinterpretation.
 

old-geezer

New member
Are you suggesting a compressor fridge does not need to have air exchange with the coach air?
That is the part I am doubting.
Isotherm is very clear that without adequate ventilation behind the unit performance will be low and power usage will be high. I actually added a fan at the top of mine just to be sure.


Installation instructions

4.1 Ventilation
It is very important that the compressor/condenser units
are well ventilated and that cold air can enter at the bottom, pass behind the fridge/freezer and warm air can leave at the top in the area where it is mounted. The natural flow of air from below and upwards behind the fridge can be increased by arranging ventilation openings at the rear.
Make sure there is a free area of 23 - 28 sq.in. below and behind the refrigerator/freezer to allow ventilation air to pass behind from below. See fig 5.
From the troubleshooting page:

Fault
Compressor runs long time but not generating enough cold.

Possible cause
Bad ventilation. Condenser too warm. Fan not working.
To much frost on evaporator.
Door not closing well.
Condenser blocked by dust.

Action
Improve ventilation for compressor. Replace fan.
Defrost.
Check door position and door seal. Clean condenser.
 

woundedpig

2018 Unity MB
Isotherm is very clear that without adequate ventilation behind the unit performance will be low and power usage will be high. I actually added a fan at the top of mine just to be sure.


Installation instructions



From the troubleshooting page:
Did you include some extra insulation of the rear compartment in your install, not closing it off completely?
 

RandyJohnson

2018 Unity TB
Makes perfect sense, but I'm still skeptical about sealing off the compressor/condenser space from the coach air as some (not you) have discussed.
I have never said that I sealed it off from the house/coach air.

I currently have a fan that is vented into the space around the MW pulling hot air from behind the fridge. When the fan is running you can feel the air coming out into the coach through the micro wave vents.

I am either going to drill a few small holes into the wall next to the entry on a Unity TB to vent into the space behind the fridge, or I am going to add two 3" duct vents similar to those on the dinette seat for the propane heater.

You will definitely need to make certain that the space behind the fridge is roughly the same temperature as the house ambient air.

I sealed the vents using HVAC tape as well as two layers of a stiff insulation board. I also added additional thinsulate against the outside wall.
 

SSTraveler

2014 LTV Unity Murphy Bed
I also insulated my outside exposed wall using several layers of Reflectix and with the sun shining on that wall and 100+ degree outside temperatures, the inside wall temp never exceeds 85 degrees. Old-geezer/Randy are right, you have to have good ventilation around the compressor Refrigerator, particularly in the back where the heat from the compressor running builds up. So the ambient temperature is even around the Refrigerator. I also added a fan that I can switch on to add more ventilation to the back space of the Refrigerator, if needed. So far I haven't needed it but I am still in the testing/getting used to the Refrigerator stage. I don't drive with my coach's AC running, fortunately my cab AC maintains a coach temperature of around 78 degrees so the Refrigerator operates no differently when driving. I believe if I can maintain the Refrigerators ambient environment temperature between 65-78 degrees I will get many years of worry free enjoyment from my new Isotherm Refrigerator, my only regret is not changing the Dometic and Hotpoint microwave out sooner!
 
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SSTraveler

2014 LTV Unity Murphy Bed
SSTraveler.

We have 710 pvs on the roof, 3000 watt inverter, and 400 aHrs lithium. Assuming full batteries we can run the AC for roughly 3 hours before the batteries are drained

Does work well if you have pets.

It also helps maintain the fridge using conditioned air.

With the alternator the batteries are fully charged even while running the AC and driving.


Sent from my iPhone using Tapatalk Pro
That's exactly what I am talking about! If I get a new Unity I am going all in on this upgrade right away. One thing I learned is that you should start making the changes you want right away even on a brand new coach.
 

SSTraveler

2014 LTV Unity Murphy Bed
I am either going to drill a few small holes into the wall next to the entry on a Unity TB to vent into the space behind the fridge, or I am going to add two 3" duct vents similar to those on the dinette seat for the propane heater.

You will definitely need to make certain that the space behind the fridge is roughly the same temperature as the house ambient temperature.
I like your idea of drilling holes. If you use three different sizes of bits, holes could look decorative, as if they have always been there. You could also put decals with circle patterns on the wall and drill holes in some of the circles for a decorative effect on vent holes.
 

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TampaSteve

2018/2019 Unity CB
That's exactly what I am talking about! If I get a new Unity I am going all in on this upgrade right away. One thing I learned is that you should start making the changes you want right away even on a brand new coach.
That's how I feel. I started tearing out things and drilling holes through the roof on my coach almost immediately upon delivery. My wife thinks I bought just for upgrading, not for travel, which is only slightly untrue.

Most of my upgrades were based on experience though. It wouldn't have occured to me to upgrade my fridge until I found out how bad the factory one was. Never having RV'd before that was a surprise.

Same thing with every project. Very first one was to install a bidet seat, after we discovered single ply tissue dissolves in your hands at the worst possible time. :)

I'm on the fence about replacing the generator with a bank of Lithium batteries though. I'm too lazy to do the math, but if you add up the potential energy of a full tank of propane running the generator its massive, more than any battery bank in the same space would hold. I like having all that for "backup" the way I camp (which is random and irregular, and often with no hookups, and we move a lot).

No doubt as the technology improves through my thoughts on that may change.
 

RandyJohnson

2018 Unity TB
That's exactly what I am talking about! If I get a new Unity I am going all in on this upgrade right away. One thing I learned is that you should start making the changes you want right away even on a brand new coach.
We took the unit out to AMSOLAR for the electrical upgrade within 30 days of receiving the coach.

Once you start making the modifications to suit your needs don't plan on trading it anytime soon.
 

Gamma1966

2013 Chassis /14 Unity MB
Likewise .. I started modifying my coach within 3 months of purchasing, first Solar, then more batteries, and so on. This is probably the last and only RV I will own, so I continue to enjoy the benefits of the upgrades I have made to the coach. Thanks to all for valuable information and feed back on the upgrade process.
 

Klipstr

2018 Wonder FTB
I'm on the fence about replacing the generator with a bank of Lithium batteries though. I'm too lazy to do the math, but if you add up the potential energy of a full tank of propane running the generator its massive, more than any battery bank in the same space would hold. I like having all that for "backup" the way I camp (which is random and irregular, and often with no hookups, and we move a lot).

No doubt as the technology improves through my thoughts on that may change.
I've been thinking the same thing. Though the generator only gets used when the Automatic Generator Start goes while the dog is in the coach and we are out and about or when we want to run the microwave for three minutes to warm up leftovers. If I were to take it out and replace with $2-3K of lithium and replace the 1000W inverter with a 2000 or 3000W that would another $1500-2500 plus trying to shoehorn it into someplace reasonable. Maybe be able to sell the generator for $1500? Still $2-3K. As you say, one can run a lot of LPG through the genny for that.

It doesn't appear to pencil...

Now, if one were starting with a clean slate on a brand new Unity or Wonder then maybe.

All that said, we've been getting acceptable performance out of our original Dometic fridge. We are apparently the lucky ones! But I still watch these posts in case something goes awry!
 

geds

2018 Serenity
My gas failure to ignite in my Dometic just reoccurred as we were leaving for a weekend trip. It happened on our previous long trip last month and we found a repair facility to remove the burner and blow it out which fixed the problem for the rest of the trip. After getting home, I shut off the fridge and refilled the propane tank, turned on and ignited the stove to insure air bubbles would be bled from the line, then restarted the fridge. Well, the gas won't ignite in the fridge again. Fortunately, we had a fridge we could transfer food to at our destination.

I seriously considered the conversion, but we ran our coach batteries completely down just running the LED lights in the evening and the vent fan during the night. There's no way a fridge would last all night without having to get up and crank the genny. Our batteries were so low, I had to crank the engine and idle for 45 min. to charge them enough to crank the genny!
 

aarpskier

2017 LTV Unity FX
... we ran our coach batteries completely down just running the LED lights in the evening and the vent fan during the night. There's no way a fridge would last all night without having to get up and crank the genny. Our batteries were so low, I had to crank the engine and idle for 45 min. to charge them enough to crank the genny!
There are dozens of very bright electical engineering types on this forum, of which I am not one! However, speaking experientially, I think you must have some other draw going on than just LED lights and fans. :thinking: With the same usage (judicious operation of LEDs, not all blazing), plus a couple of hours of television and recharging phones and computers before bedtime using the inverter, we typically see a drop of .4 - .5 amps (12.8 to 12.4 or 12.3) by morning, which is plenty to start the generator.
 

TampaSteve

2018/2019 Unity CB
On our stock flooded batteries we could run lights, a couple hours of streaming video, fans and even morning percolator usage, and only deplete about 30% of the batteries or so. (We still upgraded to Lithium as that's a bit too close for comfort with the added load of the fridge).

But probably you want something like the Victron Battery monitor to investigate. I would say possibly your batteries are shot or something else is going on. With just coach lights and a fan if I recall my monitor said a couple days remaining or something like that.

My gas failure to ignite in my Dometic just reoccurred as we were leaving for a weekend trip. It happened on our previous long trip last month and we found a repair facility to remove the burner and blow it out which fixed the problem for the rest of the trip. After getting home, I shut off the fridge and refilled the propane tank, turned on and ignited the stove to insure air bubbles would be bled from the line, then restarted the fridge. Well, the gas won't ignite in the fridge again. Fortunately, we had a fridge we could transfer food to at our destination.

I seriously considered the conversion, but we ran our coach batteries completely down just running the LED lights in the evening and the vent fan during the night. There's no way a fridge would last all night without having to get up and crank the genny. Our batteries were so low, I had to crank the engine and idle for 45 min. to charge them enough to crank the genny!
 
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geds

2018 Serenity
Sounds like I have two issues going on then. Coach batteries failing and something causing the Dometic fridge pilot light to fail igniting. Any ideas on the gas problems?
 

TJLee089

2013 Itasca Reyo 25R
I recently had occasion to "play" with the air adjustment sleeve on my Dometic RML 8555. As I recall (see manual) the igniter will try about 3 times before giving up. Listen for clicking. If the air inlet is too low, the pilot will not light. If the air is too high, the pilot will light and blow out. Once it's lit, adjust for the best looking blue flame. Hope this helps.

Sounds like I have two issues going on then. Coach batteries failing and something causing the Dometic fridge pilot light to fail igniting. Any ideas on the gas problems?
 

RichNJohn

2018 Unity MB
You can push the little temperature probe on the lower right corner of the refrigerator cooling fins up about an eighth to a quarter inch. Using it up will cause the fridge to run colder. I put a thermometer in the fridge and adjusted it up and down until I got the temperature I wanted without having to run it on the highest setting. That seemed to help some. I also have fans mounted on the cooling fins inside the fridge. they blow air directly across the fins and keep the fridge colder. An added benefit is that I get almost no frost on the fins.
https://smile.amazon.com/RV-Cooling...9339219&sprefix=rv+fridge+fan,aps,189&sr=8-15

I also use these to vent the outside compartment:
https://smile.amazon.com/Titan-Vent...ROUNPT13&sprefix=rv+fridge+fan,aps,189&sr=8-4
 

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