Isotherm frig ICT removal and test results

[booster]

Yep, I just have a rotary wired with IIRC 6 resistors to get 6 speeds. Works great with the manual thermostat.

 

[GallenH]

GeorgeRad: Thanks. I like the set-it-and-leave-it capability you guys have. Nice. Absorption fridges have a cooling ceiling of 40-60º below ambient temps. Meaning if it's 100º you're struggling. Compressor fridges do also but I believe it's more like 90º below ambient. Is that a correct estimate for compressor fridges?

 

[booster]

GeorgeRad: Thanks. I like the set-it-and-leave-it capability you guys have. Nice. Absorption fridges have a cooling ceiling of 40-60º below ambient temps. Meaning if it's 100º you're struggling. Compressor fridges do also but I believe it's more like 90º below ambient. Is that a correct estimate for compressor fridges?

I have the compressor curves around here someplace, but the 90* below ambient is probably close to what is would be. We had used our first Isotherm at 105* F with it on the sunny side and had no issues keeping the frig cool. It did use considerably more power though.

 

[GeorgeRad]

Update on ITC disaster. After multiple information exchange with Indel B USA (Isotherm) they offer, I think, the best solution to the OLED display problem of practically making my fridge useless.

The solution is well known by some of you – go back to electromechanical capillary thermostat. Indel folks understood that cost burden of necessary new controller and capillary ($400-500) was unfair for their customer so they decided to ship me a new controller and new capillary free of charge. Just received it.

After some perturbation I am truly impressed by Indel B USA customer support, with this type support my next fridge will be Isotherm.

I am hoping to replace ITC with an electronic temperature gauge hopefully utilizing the current ICT sensor inside the fridge.

 

[GeorgeRad]

Yep, I just have a rotary wired with IIRC 6 resistors to get 6 speeds. Works great with the manual thermostat.

Danfoss diagram shows 4 speeds with resistance of 0, 277, 692 and 1523 ohms. Did you split the range of 0-1.523 kOhm to 6 resistors / speeds? Thank you.

 

[booster]

Danfoss diagram shows 4 speeds with resistance of 0, 277, 692 and 1523 ohms. Did you split the range of 0-1.523 kOhm to 6 resistors / speeds? Thank you.

Exactly, I don't remember what I came up with, but mostly had to do with adding more options in the lower speed range when I was messing with the "how slow can I go" without getting too slow over recovery. If you look at the compressor curves you see efficiency go up quite a bit faster the slower you go. But, when you look at evaporator temperature vs efficiency you see even bigger gains by running the evaporator warmer.

On the new Isotherm we put in a few years ago, with all the shrouding around the freezer removed, the bulb moved to the outside of the freezer, and freezer door left open about 3/8" (like the older ones did by themselves), we get about 20* freezer temp vs below zero stock. Power use went way down that way.

Combined with a second to lowest speed, we never now even touch the knob in unit to adjust temp as it is very steady.

Here is a link to the thread where I posted the compressor data and such.

Link to thread

 

[GeorgeRad]

Thank you Booster!

 

[booster]

The solution is well known by some of you – go back to electromechanical capillary thermostat. Indel folks understood that cost burden of necessary new controller and capillary ($400-500) was unfair for their customer so they decided to ship me a new controller and new capillary free of charge. Just received it.

After some perturbation I am truly impressed by Indel B USA customer support, with this type support my next fridge will be Isotherm.

You came out much better than I did, and at the time nobody by Isotherm knew that you had to buy a new controller to go back to mechanical. I told them the ICT used 50% more energy on econ mode than my mechanical used, and they said I was crazy and basically pound sand on new controller unless I bought it and the mechanical thermostat.

The new design with the shrouded freezer that runs very cold and inefficiently, plus the ICT over doubled the energy use for the same 85L frig between the two we had.

 

[GeorgeRad]

You came out much better than I did, and at the time nobody by Isotherm knew that you had to buy a new controller to go back to mechanical. I told them the ICT used 50% more energy on econ mode than my mechanical used, and they said I was crazy and basically pound sand on new controller unless I bought it and the mechanical thermostat.

The new design with the shrouded freezer that runs very cold and inefficiently, plus the ICT over doubled the energy use for the same 85L frig between the two we had.

I wouldn’t give designers of ITC high grades; it was OK at the level of a high school project.

- Unacceptable - permanent reprogramming of Danfoss/SECOP 101N0500
- Practically impossible to set temperature setpoint without working display, it would be OK if display's lifespan would be very long but all of my four OLED displays (Isotherm and 3xBluesea) lasted about 3 years. I am changing them to either LED, LCD or an old fashion analog. Interesting note – current consumption at 12V:
- Analog Blue Sea 8254 50-0-50 A – max 1mA
- LED voltage Murata DMR20-10-DCM – max 8mA
- OLED Blue Sea Mini OLED – max 15mA