Anyone have any experience with Isotherm refrigeration systems manufactured by Great Water, Inc., either positive or negative? Thanks Morrie
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Excellent product IME
Morrie, Great Water does not manufacture - they are the U.S. distributor...and also people who provide great after-sales support, based on my experience and comments I've heard from others. Isotherm's ASU models offer a clever alternative way for the unit to draw power from the house bank, but we've found using the 'manual' mode and leaving the thermostat set where we want it for the external temps we see works best. A water-cooled unit of any manufacture will be far more efficient in power demand. We have a 5 cu. ft. icebox, well insulated but with a poorly insulated lid, enjoy rock hard ice and a small freezer section, and in numerous tests I see 30-35 amp/hrs/day in power consumption (measured by the Link 2000). All of this was in Florida & the Caribbean, at times in very high temps. One recommendation: don't use seawater for your cooling medium and avoid fouling, corrosion, etc. issues. Instead, route water from one of your FW tanks to the reefer and then return it to the tank using a 'T' e.g. to your tank's vent or fill line. We've done this on the last 2 boats and it works very well. I believe these Swedish units are well designed, well made and - after 5 years, 3 of it living aboard & cruising full-time - we only have praise for it. Jack
Morrie, Great Water does not manufacture - they are the U.S. distributor...and also people who provide great after-sales support, based on my experience and comments I've heard from others. Isotherm's ASU models offer a clever alternative way for the unit to draw power from the house bank, but we've found using the 'manual' mode and leaving the thermostat set where we want it for the external temps we see works best. A water-cooled unit of any manufacture will be far more efficient in power demand. We have a 5 cu. ft. icebox, well insulated but with a poorly insulated lid, enjoy rock hard ice and a small freezer section, and in numerous tests I see 30-35 amp/hrs/day in power consumption (measured by the Link 2000). All of this was in Florida & the Caribbean, at times in very high temps. One recommendation: don't use seawater for your cooling medium and avoid fouling, corrosion, etc. issues. Instead, route water from one of your FW tanks to the reefer and then return it to the tank using a 'T' e.g. to your tank's vent or fill line. We've done this on the last 2 boats and it works very well. I believe these Swedish units are well designed, well made and - after 5 years, 3 of it living aboard & cruising full-time - we only have praise for it. Jack
Jack - any thoughts on SP?
Passive water cooling sounds like a great idea to me. Have you run across anyone who's used the Isotherm SP?
Passive water cooling sounds like a great idea to me. Have you run across anyone who's used the Isotherm SP?
Read the FAQ and see what you think...
Jeff, we have no experience - not even a grapevine rumor or 2nd hand report - on the SP. OTOH it sounds like Isotherm's marketing response to Frigoboat and some of the other 'passive' cooling options. Frankly, I find the FAQ blurb on the SP to be over-reaching (see link). E.g. most amp consumption from a refrigeration system occurs in the compressor; the ASU water pump uses very little so 'passive cooling' isn't going to roll back the amp/hrs substantially. The 'scientifically designed fitting' (once fouling occurs and is cleaned off in a breath-defying less-than-perfect manner) is hardly going to retain its shape nor be as efficient as it's "design" intended. I don't intend to demean the idea of a passive cooling system; I just don't see it as solving a big problem, reducing the majority of the amps consumed, nor as a panacea for all inefficiencies found in a reefer system. In fact, I suspect it's evolution stems in part from all the hassles associated with a salt-water cooling addition to a reefer system. I find that the main cooling system available to the boat - the water in which it floats - controls the cooling of the fresh water circulating in our reefer system just fine. Sometimes I think the global economy is controlled by the marketing folks, you know?! Jack
Jeff, we have no experience - not even a grapevine rumor or 2nd hand report - on the SP. OTOH it sounds like Isotherm's marketing response to Frigoboat and some of the other 'passive' cooling options. Frankly, I find the FAQ blurb on the SP to be over-reaching (see link). E.g. most amp consumption from a refrigeration system occurs in the compressor; the ASU water pump uses very little so 'passive cooling' isn't going to roll back the amp/hrs substantially. The 'scientifically designed fitting' (once fouling occurs and is cleaned off in a breath-defying less-than-perfect manner) is hardly going to retain its shape nor be as efficient as it's "design" intended. I don't intend to demean the idea of a passive cooling system; I just don't see it as solving a big problem, reducing the majority of the amps consumed, nor as a panacea for all inefficiencies found in a reefer system. In fact, I suspect it's evolution stems in part from all the hassles associated with a salt-water cooling addition to a reefer system. I find that the main cooling system available to the boat - the water in which it floats - controls the cooling of the fresh water circulating in our reefer system just fine. Sometimes I think the global economy is controlled by the marketing folks, you know?! Jack
Isotherm and SP
I installed the Isotherm unit in my 35.5 several years ago. I also went with the SP as I didn't want anymore holes in the bottom of my boat than already existed. I run it in the manual mode so I can adjust the temperature to the exact point that I want. I divided my box into two halfs and freeze ice cubes in the freezer side. The only thing to be aware of is that there are two models of units and Great Water doesn't mention it. The normal model goes through an automatic defrost every 10 days. The defrost cycle is that it turns itself off and lets the box warm up until the frost melts. This is a little hard on the ice cubes and perishable food. The other model has to be defrosted manually. I use a hair dryer and it is so quick that the beer and ice stay cold. I don't have any way to measure power comsumption other that watching the running time and the number of amps being drawn when it is running. It seems to be off as much as it is on and uses about 3 to 4 amps when running. I have to change the manual setting from summer (100 +) to winter (40 ) in order to freeze ice and not the cokes in the other side. Attached is a picture of the compressor and thru hull under the sink.
I installed the Isotherm unit in my 35.5 several years ago. I also went with the SP as I didn't want anymore holes in the bottom of my boat than already existed. I run it in the manual mode so I can adjust the temperature to the exact point that I want. I divided my box into two halfs and freeze ice cubes in the freezer side. The only thing to be aware of is that there are two models of units and Great Water doesn't mention it. The normal model goes through an automatic defrost every 10 days. The defrost cycle is that it turns itself off and lets the box warm up until the frost melts. This is a little hard on the ice cubes and perishable food. The other model has to be defrosted manually. I use a hair dryer and it is so quick that the beer and ice stay cold. I don't have any way to measure power comsumption other that watching the running time and the number of amps being drawn when it is running. It seems to be off as much as it is on and uses about 3 to 4 amps when running. I have to change the manual setting from summer (100 +) to winter (40 ) in order to freeze ice and not the cokes in the other side. Attached is a picture of the compressor and thru hull under the sink.
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