12V Compressor Refrigerators

[eric1514]

Ok, so I ordered a Novacool R3100 refrigerator. Novacool's lead time is 5 weeks so it will be a while until I install it.

I wanted to put this Norcold N1090 in but the cheapest price I found was almost $2100 delivered. The Norcold is half that and only .2 cf smaller.

Should be an adventure. Any advice or experience will be greatly appreciated.

[rowiebowie]

Originally Posted by eric1514

Ok, so I ordered a Novacool R3100 refrigerator. Novacool's lead time is 5 weeks so it will be a while until I install it.

I wanted to put this Norcold N1090 in but the cheapest price I found was almost $2100 delivered. The Norcold is half that and only .2 cf smaller.

Should be an adventure. Any advice or experience will be greatly appreciated.

Eric, our 7 yr. old Novacool R3100 (3.1 cf) works great and is pretty efficient. Yes, it's the biggest single drain on the two coach batteries, but we've had no problem running it 12-15 hours overnight while boon docking.

I didn't know they still made that model. Just in case I jinx'd ours by talking good about it and it dies tomorrow, do you mind saying how much it cost?
.

[eric1514]

Originally Posted by rowiebowie

Eric, our 7 yr. old Novacool R3100 (3.1 cf) works great and is pretty efficient. Yes, it's the biggest single drain on the two coach batteries, but we've had no problem running it 12-15 hours overnight while boon docking.

I didn't know they still made that model. Just in case I jinx'd ours by talking good about it and it dies tomorrow, do you mind saying how much it cost?
.

The width of the unit was the most important factor in choosing the fridge. It had to fit in the existing cabinet.

I bought it from these guys. CamperVan-HQ. They sell the basic unit for $975. $150 shipping and $60 for the Stainless Steel door panel. That's the best price I could find and like I said, 1/2 the price of the Norcold I originally wanted. The drag is that it's 5 weeks away. But that's with everybody.

[rowiebowie]

Originally Posted by eric1514

The width of the unit was the most important factor in choosing the fridge. It had to fit in the existing cabinet.

I bought it from these guys. CamperVan-HQ. They sell the basic unit for $975. $150 shipping and $60 for the Stainless Steel door panel. That's the best price I could find and like I said, 1/2 the price of the Norcold I originally wanted. The drag is that it's 5 weeks away. But that's with everybody.

Thanks. I agree size is important that it fit, or then you're into time-consuming cabinet work. The fridge, microwave, and furnace are the only major appliances I've not had to rework or replace. That's why I was curious about price. Mine would just be quick swap out, but an expensive swap, if it came to that. Hope I didn't just jinx myself.
.

[eric1514]

My refrigerator arrived yesterday. I unboxed it and ran some jumper cables from my wife's car battery to the unit just to make sure it worked and it did.

There is a fan mounted in a strange location on the back of the fridge. It points at the control module why I don't know. The air just smacks the side of the module and spreads out indiscriminately after that. It comes on and off with the compressor but doesn't cool the compressor or the condenser coils. I may reposition this fan to blow across the coils from the bottom or add another to the same terminals. My intention is to use the existing vents in the van and build a chimney using rigid foam insulation as close to the back of the fridge as possible.

Unfortunately, I'm busy for the next 3 weeks so this will all have to wait.

[mikeehlert]

Originally Posted by eric1514

My refrigerator arrived yesterday. I unboxed it and ran some jumper cables from my wife's car battery to the unit just to make sure it worked and it did.



There is a fan mounted in a strange location on the back of the fridge. It points at the control module why I don't know. The air just smacks the side of the module and spreads out indiscriminately after that. It comes on and off with the compressor but doesn't cool the compressor or the condenser coils. I may reposition this fan to blow across the coils from the bottom or add another to the same terminals. My intention is to use the existing vents in the van and build a chimney using rigid foam insulation as close to the back of the fridge as possible.



Unfortunately, I'm busy for the next 3 weeks so this will all have to wait.

That random fan may be needed to cool the control module?

[rowiebowie]

Originally Posted by mikeehlert

That random fan may be needed to cool the control module?

Could be. Or at least I've heard of this fan position before. Still, it sounds like a strange position for it.

[GeorgeRa]

On my 85l Isotherm I have the fan cooling the condenser and the compressor, if your condenser is separate from compressor cooled by convection the fan could be use to cool off the compressor.

I replaced the factory fan with a very quiet one.

[eric1514]

Here's a pic of how they mounted the fan

That fan blows toward the module and not much reaches the compressor. It must work. They've been doing it for years.

However, I'd like to either 1)add another similar fan to the same terminals put pointing up at the coils or 2)add a thermostatically controlled fan that comes on depending on the coil temp.

The first option is easy I think. I don't imagine the small draw of a fan will upset anything in the module, but I'd rather do option 2 if I can locate a suitable fan and thermostat. Any ideas?

[booster]

Originally Posted by eric1514

Here's a pic of how they mounted the fan

That fan blows toward the module and not much reaches the compressor. It must work. They've been doing it for years.

However, I'd like to either 1)add another similar fan to the same terminals put pointing up at the coils or 2)add a thermostatically controlled fan that comes on depending on the coil temp.

The first option is easy I think. I don't imagine the small draw of a fan will upset anything in the module, but I'd rather do option 2 if I can locate a suitable fan and thermostat. Any ideas?

IIRC from when we were looking at frigs a decade ago, the fan on the Novacool was optional then. My guess would be they took their normal, gravity model and just added the fan, explaining the less than thought out location. The other brands were starting to come with fans so may have been a sales thing, even. I would be careful about just adding more fan to the module output, as the last coupe of things I have cecked on doing that to, like our Magnum inverter/charger, were already maxed out and more would ruin the board. A call to Novacool may be best.



I think it may give more benefit if the gravity intake air was ducted to the compressor area and separately to a close fitting chimney for the coils. Use whatever fans in the ducts either the intake or a sealed until out of the body discharge ducts.

[rowiebowie]

Originally Posted by eric1514

Here's a pic of how they mounted the fan

That fan blows toward the module and not much reaches the compressor. It must work. They've been doing it for years.

However, I'd like to either 1)add another similar fan to the same terminals put pointing up at the coils or 2)add a thermostatically controlled fan that comes on depending on the coil temp.

The first option is easy I think. I don't imagine the small draw of a fan will upset anything in the module, but I'd rather do option 2 if I can locate a suitable fan and thermostat. Any ideas?

Other than another slight power drain, there is nothing wrong with adding another fan. However, a fan is no substitute for ventilation.

My Airstream Avenue fridge was installed without Novacool's suggested minimum 30 square inches of lower vent. In fact, there was no lower vent on the original install. And upper ventilation was only the grill around the microwave install.

I cut several 3" holes in the door panel beneath the fridge that covered the inverter/charger and breaker panel. Still not enough, so I added a small 16cfm squirrel cage fan behind the fridge that vents through a flexible tube into the back lounge area. It is wired to to an off/on switch through a button thermostat (on at 100 degrees/off at 85). My goal was to evacuate the hot air behind the fridge with coach air that would normally be 10-30 degrees cooler.

[eric1514]

Originally Posted by booster

IIRC from when we were looking at frigs a decade ago, the fan on the Novacool was optional then. My guess would be they took their normal, gravity model and just added the fan, explaining the less than thought out location. The other brands were starting to come with fans so may have been a sales thing, even. I would be careful about just adding more fan to the module output, as the last coupe of things I have cecked on doing that to, like our Magnum inverter/charger, were already maxed out and more would ruin the board. A call to Novacool may be best.



I think it may give more benefit if the gravity intake air was ducted to the compressor area and separately to a close fitting chimney for the coils. Use whatever fans in the ducts either the intake or a sealed until out of the body discharge ducts.

I'm also leery of adding another fan to the terminals and will definitely ask NovaKool before I do. I will also ask them if there would be any harm or benefit in moving their fan to a location that better covers the coils.

Originally Posted by rowiebowie

Other than another slight power drain, there is noting wrong with adding another fan. However a fan is no substitute for ventilation.

My Airstream Avenue fridge was installed without Novacool's suggested minimum 30 square inches of lower vent. In fact, there was no lower vent on the original install. And upper ventilation was only the grill around the microwave install.

I cut several 3" holes in the door panel beneath the fridge that covered the inverter/charger and breaker panel. Still not enough, so I added a small 16cfm squirrel cage fan behind the fridge that vents through a flexible tube into the back lounge area. It is wired to to an off/on switch through a button thermostat (on at 100 degrees/off at 85). My goal was to evacuate the hot air behind the fridge with coach air that would normally be 10-30 degrees cooler.

An additional fan would be my preference, especially one that was temperature controlled but honestly, it's starting to get above my pay grade.

I saw this fan on Amazon. LINK

I thought I could couple that with this thermostat. LINK

The problem I have is where and how to mount it (on the coils? just in the cabinet?) and what temperature range should it operate at.

[avanti]

I second Rowiebowie's recommendation to force-ventilate the back of the cabinet that contains the fridge. I added two computer pancake fans thermostatically speed-controlled by a little board I got from eBay. Made a huge difference, and the fans only run when necessary.

[booster]

Originally Posted by avanti

I second Rowiebowie's recommendation to force-ventilate the back of the cabinet that contains the fridge. I added two computer pancake fans thermostatically speed-controlled by a little board I got from eBay. Made a huge difference, and the fans only run when necessary.

A lot depends on the original setup, I think. The venting is completely different for us because we have external hi and low vents from the propane frig to use. Internal venting is totally different.


IIRC, Eric has a 2015 Travato, and I don't recall if he has outside vents or not on that.

[avanti]

Originally Posted by booster

A lot depends on the original setup, I think. The venting is completely different for us because we have external hi and low vents from the propane frig to use. Internal venting is totally different.


IIRC, Eric has a 2015 Travato, and I don't recall if he has outside vents or not on that.

Certainly true. My comment implicitly assumed that the air in the vicinity of your fridge coils tends to rise significantly above ambient. If it doesn't, then it ain't broke, so don't fix it.

[rowiebowie]

Originally Posted by avanti

Certainly true. My comment implicitly assumed that the air in the vicinity of your fridge coils tends to rise significantly above ambient. If it doesn't, then it ain't broke, so don't fix it.

That is exactly the problem with my compressor fridge. Besides not being installed by Airstream to product minimum ventilation recomendations, it sits about midway up on the driver's side. This places it directly behind the black (fake window) stripe on my silver van. In addition to dark skin, the area behind the fridge was poorly (even lacking insulation) in several places. This is why I've always figured Airstream gave their insulation guy only half of what he needed and told him to "Do the best you can".

I added spray foam, fiberglass, and reflectix to the areas I can reach and lowered temperatures about 10 degrees behind and above the fridge. But with a very poor convection path (heat has to curl forward over the top of the microwave and out the front), I figured a fan was the only way to go. Still, at 16 cfm rating, the fan takes a surprising amount of time to lower the temperature behind the fridge. But the thermostat comes on at 100 degrees https://www.amazon.com/Thermostat-Sw...ARAJSJF72H4XC1

Originally Posted by eric1514

I thought I could couple that with this thermostat. LINK

The problem I have is where and how to mount it (on the coils? just in the cabinet?) and what temperature range should it operate at.

I believe 130 degrees is way too late for a thermostat to engage and I doubt the temp will ever reach that high anyway.

Did you replace another compressor fridge or was your original an absorption model with outside vents? It depends on your Travato model what it came with, but as Booster mentioned, it certainly makes a difference in where and what type of fan you install.

[avanti]

You should seriously consider one of these computer fan controllers:

fan controller.jpg

Many similar ones are available. The advantage is that the fan speed is continuously modulated via PWM, according to the temperature. The result is that the fan is almost always nearly silent and the temperature never goes up. Works really well.

[rowiebowie]

I know only enough about electrical wiring to keep me from hurting myself or the items I'm wiring. I got good advice on this forum, yet did not understand it until I made my own sketch of how the wiring should go.

Here's a crude drawing of the wiring of my fan controlled with a button thermostat and lighted on/off switch. The button thermostat can be wired +/- to either prong as it simply passes the current through when closed.

[avanti]

Originally Posted by rowiebowie

I know only enough about electrical wiring to keep me from hurting myself or the items I'm wiring. I got good advice on this forum, yet did not understand it until I made my own sketch of how the wiring should go.

Here's a crude drawing of the wiring of my fan controlled with a button thermostat and lighted on/off switch.

With the PCM fan controller, you can eliminate both the switch and the button thermostat. Just power the fan from the same circuit as the fridge, and everything will take care of itself. BTW: Many compressor fridges have "fan" outputs that will automatically activate the fan circuit whenever the compressor runs.

[rowiebowie]

My fan install was not to blow over the fridge coils, but to exchange the hot air behind the fridge with cooler air from the coach. Plus, only 4 screws allow me to remove the Microwave and access the area (no removing the fridge). There's no need for the fan to run on most of our trips since we travel in mild/cooler weather, so quieter and less battery drain with the separate squirrel cage fan on it's own switch.

EDIT: When I posted, I didn't know if going the PCM fan controller route would run only/always when the compressor engaged. I guess I assumed that was the case. However, my big problem was not the fan install and the wiring, but finding a space to drill a 1 1/2" hole and routing space for the tubing. Talk about using every square inch! Airstream left no where else to go except behind the rear wardrobe panel (up high where the original roof bracing forced Airstream to leave a little space) was where I had to fish the flexible tubing. It was the difficult part. Airstream could have done a proper install, but chose not to.