Finishing up on the ICT removal and mechanical thermostat reinstall on our 3.0cf Cruise Elegance frig. I also added a power on/off switch to remove all power from the frig so it can be ventilated without the light staying on, and put on a compressor speed 6 position selector switch. Long haul and expensive to get rid of the ICT after the temp sensor failed after one trip. The ICT reprogrammed the compressor control module so it had to be replaced, of all things. Totally ridiculous to make a product that way as it prevents using a simple thermostat as backup or if you just don't like the ICT as it is a kind of not great performer also.
Here are the power switch by the side of the frig door, and speed control in the kitchen above the frig along with our digital wireless frig thermometer.
The speed control is a 6 position selector switch in the thermostat wiring to the compressor module. One no resistance jumper and 5 different resistor values to give 6 speeds from 2000rpm to 3500rpm. The mounting is a piece of PVC drain line pipe and two discs of PVC sheet. Bottom is bigger to give the flange and is cemented on with pipe cement, and the top is the access and is screwed on. Two bullet connectors on the wiring in the mount.
Based on our old frig of the same size and brand we knew that 2000rpm is good almost all the time and finding the right combo of things to get the desired frig and freezer temps along with slow speed, could save a lot power use. The old frig freezer door did not shut tightly and new one does fit tightly and a different shroud on the freezer box and different drip tray meant starting from scratch to get the right temps.
I quickly found out the thermostat was also different on the new frig, and could only get to 20*F as the highest freezer temp even after max ranging the calibration screw adjustment. That was good for us though as don't do ice cream or long term storage in it. Stock the freezer ran a 6*F so used a lot more energy because of the colder evaporator. Stock it also ran at a bit under 3000rpm so that is less efficient.
After some messing around with the drip tray position, I found that the frig got to 37/39*F with the tray in place, but pulled away from the back of the frig as far as possible. Freezer held at 19-21*F. Both very good for how we want it to run.
It appeared to me that the frig was hardly running much, but did run a 24hr test on it to see what the actual energy use was.
Test conditions were the above frig temps, ambient 67*F steady, inside the shop so no wind or sun. Most of the test was run on shore power float charge at 13.1v and some on battery at high 12v range. Voltage didn't matter as I was measuring cumulative watt hours on a Wattsup hardwired into the power wire at the frig. Watt hours were converted to amp hours at 12.4v which would normally be a worst case average for us as we have a lot of battery and moderate use, plus solar holding up the voltage for nearly half the time if decent sun.
The results were very surprising to me.
24 hour watt hour usage was 177.7 watt hours.
At 12.4v that is 14.33 amp hours and very low for any frig. It is about 1/2 of what the frig in stock form and what on the ICT in the same conditions, even with the ICT in economy mode. It is also about 20% lower than similar testing I did on our old frig.
Of course real world use will be substantially more as we commonly saw 30-50% more power use in real life than controlled optimized testing, but even at 50% higher it would be very low power use for any frig. It will be interesting to see how it does in real life. I did set up the wiring with Delphi connectors so the Watts up is very easy to put in and out, and it can be reset by cycling the on/off frig switch so easy to use.
I am very glad to see the ICT and it's 6* temp swings and high energy use gone for good. Should never have believed the literature claims.
I probably will run a shorter timed energy use with the drip tray pushed all the way in to it's normal place as that should give 40-41* in the frig, which is the normal spec point for Isotherm. I will also turn up the shop heat to 77* for the test as that is also there standard test point. The lower frig temp should save some energy, but the warmer ambient should cost some energy so it will be interesting to see how that balances out.
Here are the power switch by the side of the frig door, and speed control in the kitchen above the frig along with our digital wireless frig thermometer.
The speed control is a 6 position selector switch in the thermostat wiring to the compressor module. One no resistance jumper and 5 different resistor values to give 6 speeds from 2000rpm to 3500rpm. The mounting is a piece of PVC drain line pipe and two discs of PVC sheet. Bottom is bigger to give the flange and is cemented on with pipe cement, and the top is the access and is screwed on. Two bullet connectors on the wiring in the mount.
Based on our old frig of the same size and brand we knew that 2000rpm is good almost all the time and finding the right combo of things to get the desired frig and freezer temps along with slow speed, could save a lot power use. The old frig freezer door did not shut tightly and new one does fit tightly and a different shroud on the freezer box and different drip tray meant starting from scratch to get the right temps.
I quickly found out the thermostat was also different on the new frig, and could only get to 20*F as the highest freezer temp even after max ranging the calibration screw adjustment. That was good for us though as don't do ice cream or long term storage in it. Stock the freezer ran a 6*F so used a lot more energy because of the colder evaporator. Stock it also ran at a bit under 3000rpm so that is less efficient.
After some messing around with the drip tray position, I found that the frig got to 37/39*F with the tray in place, but pulled away from the back of the frig as far as possible. Freezer held at 19-21*F. Both very good for how we want it to run.
It appeared to me that the frig was hardly running much, but did run a 24hr test on it to see what the actual energy use was.
Test conditions were the above frig temps, ambient 67*F steady, inside the shop so no wind or sun. Most of the test was run on shore power float charge at 13.1v and some on battery at high 12v range. Voltage didn't matter as I was measuring cumulative watt hours on a Wattsup hardwired into the power wire at the frig. Watt hours were converted to amp hours at 12.4v which would normally be a worst case average for us as we have a lot of battery and moderate use, plus solar holding up the voltage for nearly half the time if decent sun.
The results were very surprising to me.
24 hour watt hour usage was 177.7 watt hours.
At 12.4v that is 14.33 amp hours and very low for any frig. It is about 1/2 of what the frig in stock form and what on the ICT in the same conditions, even with the ICT in economy mode. It is also about 20% lower than similar testing I did on our old frig.
Of course real world use will be substantially more as we commonly saw 30-50% more power use in real life than controlled optimized testing, but even at 50% higher it would be very low power use for any frig. It will be interesting to see how it does in real life. I did set up the wiring with Delphi connectors so the Watts up is very easy to put in and out, and it can be reset by cycling the on/off frig switch so easy to use.
I am very glad to see the ICT and it's 6* temp swings and high energy use gone for good. Should never have believed the literature claims.
I probably will run a shorter timed energy use with the drip tray pushed all the way in to it's normal place as that should give 40-41* in the frig, which is the normal spec point for Isotherm. I will also turn up the shop heat to 77* for the test as that is also there standard test point. The lower frig temp should save some energy, but the warmer ambient should cost some energy so it will be interesting to see how that balances out.
