Isotherm frig ICT removal and test results

[GeorgeRa]

Originally Posted by avanti

But couldn't one control the speed by simulating that speed resistor thing? Or is that not there anymore?

Still is, didn’t change with newer SECOPs. These are ICT available functions, no clue which one required reprogramming, perhaps soft start.

[booster]

Originally Posted by Davydd

With ARV I have a three year bumper to bumper warranty of everything they did or put in. I am not going to carry spare parts on the come for the first three years. For instance I had a VB air suspension bag leak and they overnighted the parts to a MB Sprinter dealer where I was at in Texas and the dealer installed it and I was out before noon. In Phoenix they did the same with the Nations second alternator replacement and I got in and out again before noon. I don't know how they do it but they do it and promptly.

Can't blame you for that, but I do think it would be nice if you contacted ARV and asked about it so they can check it out and if there would be an issue they could decide to stock or not stock parts or come up with another way. If something happens and you have the same issue you would with an ITC, warranty won't matter, and if ARV doesn't know about the issue and way to get around it, your trip is still ruined.

[@Michael]

Originally Posted by avanti

So, is there any particular reason one couldn't build a DIY fridge controller with an Arduino-class device and some temperature sensors? Does not look like rocket science.

If only to replace the function of the thermostat, I'd guess yes. If one were to try to replace the functionality of the electronic module, I suspect it would be difficult.

Here's a couple of threads where attempts are being made to repair the modules:

https://www.cruisersforum.com/forums...ms-218711.html

https://www.cruisersforum.com/forums...ol-184322.html

[Davydd]

I carry a large Igloo cooler mostly for miscellaneous storage that can be used in an emergency if the refrigerator malfunctions. Refrigerator loss will not ruin my trips. It will be inconvenienced. I placed the refrigerator conveniently 18" off the floor to create an open notch used for many things like my custom ladder to the bunk bed, shoes, and sometimes a kitty litter tray when we bring our cat. It can serve to store a cooler in an emergency. It sits on a shelf in our vertical back storage of adjustable shelves and 27 cubic feet of storage.

[avanti]

Originally Posted by @Michael

If only to replace the function of the thermostat, I'd guess yes. If one were to try to replace the functionality of the electronic module, I suspect it would be difficult.

Here's a couple of threads where attempts are being made to repair the modules:

https://www.cruisersforum.com/forums...ms-218711.html

https://www.cruisersforum.com/forums...ol-184322.html

I certainly wouldn't attempt to replace the SECOP controller. But, a homemade electronic thermostat/temperature controller looks pretty doable. Adding sensible "smarts" would be easy and fun. I may give this a try eventually, but my list of projects for our new rig is getting mighty long.

[avanti]

Originally Posted by avanti

Looks like the Cruise 195 may be a good compromise, both size-wise and cost. Looks like a nice step up from the NovaKool.

We've looked carefully, and the choice is down to another NovaKool RFU6800 or the Isotherm Cruise 195. All the other obvious choices are either too wide for our space or have too small a freezer. Here are the tradeoffs:

NovaKool pros:
--less expensive
--known quantity
--a bit narrower
--slightly larger freezer

Isotherm pros:
--dual compressors
--slightly larger total capacity
--seemingly somewhat higher build quality
--adjustable shelves

Close call. Thoughts?

[GeorgeRa]

The Isotherm's picture shows electromechanical thermostat in the fridge compartment but not in the freezer so how is freezer temperature controlled. If there are 2 thermostats independent control could be great.

Nova Cool fridge with one thermostat, seems as mechanical thermostat. Bothe chambers have seperate evaporating plates, could have difficulties controlling both chambers temperatures correctly.

If you plan is to go with a large battery bank I would go with Isotherm.

I would check if Isotherm is not using electronic thermostat(s) like ICT or similar, their online onfo could outdated.

[avanti]

Originally Posted by GeorgeRa

The Isotherm's picture shows electromechanical thermostat in the fridge compartment but not in the freezer so how is freezer temperature controlled. If there are 2 thermostats independent control could be great.

There are separate stats. Parts diagram found here:
Parts List Diagrams : Isotherm-Parts, Isotherm Marine Refrigeration and Parts

Nova Cool fridge with one thermostat, seems as mechanical thermostat. Bothe chambers have seperate evaporating plates, could have difficulties controlling both chambers temperatures correctly.

Yes, NovaKool has only one mechanical stat. We get by with it, but it is not great. Definitely no rock-hard ice cream.

I wonder what the power implication is for dual compressors. I could actually see it going either way, though likely some penalty. I am told that startup takes a lot of power, and there would be more of those, probably.

[GeorgeRa]

Originally Posted by avanti

There are separate stats. Parts diagram found here:
Parts List Diagrams : Isotherm-Parts, Isotherm Marine Refrigeration and Parts


Yes, NovaKool has only one mechanical stat. We get by with it, but it is not great. Definitely no rock-hard ice cream.

I wonder what the power implication is for dual compressors. I could actually see it going either way, though likely some penalty. I am told that startup takes a lot of power, and there would be more of those, probably.

Perhaps it is time to think about soft start. Two compressors will work at lower duty cycles, finding efficiency energy vs power draw could help to make a decision. I think I have seen it somewhere in the vast Danfoss library.

[booster]

I would have to agree on the two compressor system, if it has to thermostats being a huge deciding factor. A single compressor and an adjustable cold air between frig and freezer works fine on home frigs, we have one currently, but when you get to highly variable conditions that a frig sees in a a camper a single has some balance between frig and freezer issues. We all see that.


My huge disqualifier would be if the Isotherm is using their electronic controls of any sort. They just don't do a good job with them, IMO. If it could be had with two mechanical thermostats, you would be able to put on either a manual speed and temp control system on each, or the home automation style you spoke of designing. By starting the compressors on the lowest speed, you can reduce the load and be easier on the compressor. Probably not as good as a soft start, but better than starting at higher speeds and loads. Two compressors probably would use a bit more power, but if you ran the freezer at the warmer temp that NovaKool does, you probably would be close.



Interesting choices to consider, good luck with it.

[avanti]

Originally Posted by booster

I would have to agree on the two compressor system, if it has [two] thermostats being a huge deciding factor.

Originally Posted by GeorgeRa

If you plan is to go with a large battery bank I would go with Isotherm.

OK. One decision made.
I am holding the two of you personally responsible.

[GeorgeRa]

Originally Posted by avanti

OK. One decision made.
I am holding the two of you personally responsible.

Make sure that whoever is going to convert your van follows Isotherm instruction.

You could consider floor vent hole, Dave Orton had them in both of his conversions and strongly recommends them. It could open only if needed. https://sprinter-source.com/forums/i...6/#post-879254.

Either backdraft or motorized valve could be used https://www.amazon.com/Fincos-Plasti...07RQF86YS?th=1

For my small fridge I didn’t find it necessary but with large fridge it could help in hot days.

[avanti]

Originally Posted by GeorgeRa

Make sure that whoever is going to convert your van follows Isotherm instruction.

You could consider floor vent hole, Dave Orton had them in both of his conversions and strongly recommends them. It could open only if needed.
...
For my small fridge I didn’t find it necessary but with large fridge it could help in hot days.

Nah. Not necessary. Internal venting is fine.

If you think about it, all that heat that is being pumped out of the fridge is coming from inside your van, so there is no net heating, beyond whatever electricity the unit consumes.

[Remember: This is not significantly bigger than our current fridge, so I have data.]

[GeorgeRa]

Originally Posted by avanti

........................
If you think about it, all that heat that is being pumped out of the fridge is coming from inside your van, so there is no net heating, beyond whatever electricity the unit consumes.

Correct, didn't think this way.