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Boat Forum / Cruising / July 2006Cool Mate CLM12KC Air Conditioner power draw
This weekend I measured the actual power draw on our Cool Mate CLM12K (12,000 BTU) air conditioner and found that it was drawing 12 amps at 124V AC instead of the 9.1 amps claimed on the Dometic website. http://www.marineair.com/pdfs/L-2124.pdf Is there something wrong with my unit, or is it just a case of "specmanship". I'm wondering if the spec sheet power may be for the unit itself without the necessary sea water pump running. 12 amps is 33% higher than the spec. Anyone know? Don W. Don W <donw_s11atswbelldotnet@figure.it.out> wrote in news:m_6xg.134232 $dW3.29016@newssvr21.news.prodigy.com: > This weekend I measured the actual power draw on > our Cool Mate CLM12K (12,000 BTU) air conditioner > and found that it was drawing 12 amps at 124V AC > instead of the 9.1 amps claimed on the Dometic > website. How much it draws is heavily dependent on its condensor temperature, which changes the pressure the compressor has to work against. Monitor its current and let it stabilize at 12A. Spray some water into the side of the case so the fan can suck it into the condensor and watch the load ease on the compressor. The unit will probably draw less current after it has been running a few hours so the case fills up with condensate water. There is a slinger ring around the fan that blows through the hot condensor. This ring picks up water from the pan it's built on and throws it up in the airflow to the condensor, water cooling it with distilled condensate water from the evaporator, exactly like a $99 cheap window air conditioner, which is what the coolmate really is. Once the water supply has been condensed and run outside into the slinger, it'll cool the condensor much better, dropping your current drain. It's also drawing more current because you're applying more voltage to the unit than it was designed for, which doesn't really hurt it. The plate probably says 115VAC, not 124VAC you measured. If you're thinking about driving it with a generator or inverter, plan on providing it with TWICE the running current drain, 24A AC, so you can START it. It draws a LOT of current for a couple of seconds when it starts. The genset must provide this starting power (the peak rating on the genset) without tripping out or sagging voltage too far. A 3KW genset is about right for this unit....but not a 1500W. I'm pulling TWO 8000 Btu LG Electronics Korean window units to cool my stepvan shop. There's also a 2.7 cu ft R-12 fridge that starts all at the same time off a Honda EU3000i electronic inverter superquiet genset mounted permanently on the back. If it'll pull that load, it'd be great for your unit. Now, put all that test equipment away, get a cold alcoholic beverage out of the cooler and go sit in front of the Coolmate before you get a notion to take the cabinet off to see what's wrong and screw it all up! > Don W <donw_s11atswbelldotnet@figure.it.out> wrote in news:m_6xg.134232 >>This weekend I measured the actual power draw on [quoted text clipped - 18 lines] > and run outside into the slinger, it'll cool the condensor much better, > dropping your current drain. Well, the only problem with this theory is that the condensor is raw water (sea water in this case) cooled. The cooling water comes from a seawater pump attached to a thru-hull. > It's also drawing more current because you're applying more voltage to > the unit than it was designed for, which doesn't really hurt it. The > plate probably says 115VAC, not 124VAC you measured. True. I considered that, but the current draw is 33% higher, and 9V out of 115V is only about 8% or so. <good advice snipped> > Now, put all that test equipment away, get a cold alcoholic beverage out > of the cooler and go sit in front of the Coolmate before you get a notion > to take the cabinet off to see what's wrong and screw it all up! ;-) Actually, I'm considering doing something worse, which is relocating the unit to somewhere else in the boat. Right now, its completely taking up the only closet that has any hang-up space in the rear cabin :-( Don W. Don W <donw_s11atswbelldotnet@figure.it.out> wrote in news:LYexg.11933 $2v.9985@newssvr25.news.prodigy.net: > Well, the only problem with this theory is that > the condensor is raw water (sea water in this > case) cooled. The cooling water comes from a > seawater pump attached to a thru-hull. Oh, sorry, I must have been thinking CarryCool, the portable one. Ignore the rest of my post. How hot does the seawater condensor feel? Can you hang onto it, comfortably? Now it sounds like low cooling water capacity/clogged strainers-hoses-condensor-outlet problems. The problem remains the same....too much backpressure on the compressor, which usually means high head pressure from too little flow on water-cooled condensors. Do you have a set of refridgeration guages? We need to see those pressures to assess pressure problems. You could also have clogged capillary tubes feeding the evaporator from a dirty system. Gotta get some guages on them and you'll need a probe thermometer we can stick into the evaporator core, one of those little pocket ones AC people keep in their pockets. If the condensor is hot, the pressure really stalls the compressor raising the current you're measuring. The damned cheap seawater pumps that feed these units are crap. They don't prime themselves and if the boat heels over with the thru-hull valve left open, they'll get air in them, maybe not enough to go completely dry, but enough to make flow just awful. What I've done to a few of them is to put a T on the seawater pump outlet, one to the condensor to cool the AC and the other to just an open-ended valve I can flip open to let the air out of the pump so it'll fully prime and let the bubbles out. The damned strainers sold for these things is way too fine! Any creepy crawlers that can pass through the condensor on the AC SHOULDN'T be filtered out by the strainers...clogging them in a week, here. I've changed out the strainers to ones with perforated metal sleeves, instead of those fine screens. If it sucks up something big, it stops it. If it sucks up a little crawler, it feeds him through the system and pours his partially cooked guts over the side, making the crabbing under the boat improved...(c; Is lots of water pouring out of the boat outlet and the seawater condensor cool enough to hang onto?..... > Don W <donw_s11atswbelldotnet@figure.it.out> wrote in news:LYexg.11933 > $2v.9985@newssvr25.news.prodigy.net: [quoted text clipped - 12 lines] > same....too much backpressure on the compressor, which usually means high > head pressure from too little flow on water-cooled condensors. I need to check the water flow. It has been flowing just fine, but it has been a few weeks since I specifically checked it. The unit is installed in the closet with the evaporator right behind the door. The door has the typical louver slots in it which lets the return air into the unit. The problem is that it is next to impossible to get to the back side of the unit due to space restrictions, so I have no idea how hot the condenser is running. > Do you have a set of refridgeration guages? We need to see those > pressures to assess pressure problems. You could also have clogged > capillary tubes feeding the evaporator from a dirty system. Gotta get > some guages on them and you'll need a probe thermometer we can stick into > the evaporator core, one of those little pocket ones AC people keep in > their pockets. I do have a set of R12/R22 gauges as well as a new set of R134A gauges. Since the unit is R22 based, I guess I could hook up the gauges and read the condenser temperature off of the high pressure gauge. Maybe I'll do that next time I go down to the boat. I think I'll also contact Cool Mate, and find out what the current draw should be with the sea water pump running. > If the condensor is hot, the pressure really stalls the compressor > raising the current you're measuring. The damned cheap seawater pumps [quoted text clipped - 17 lines] > Is lots of water pouring out of the boat outlet and the seawater > condensor cool enough to hang onto?..... Well, there was a lot of sea water pouring out of the outlet last time I checked, but that has been a month or so ago, and before I measured the current. Its a good thought to check the flow, and see if that is why the current is high. Don W. Don W <donw_s11atswbelldotnet@figure.it.out> wrote in news:6Dpxg.179658$F_ 3.148605@newssvr29.news.prodigy.net: > Maybe I'll do that next time I go down to > the boat. Is it running now? "Next time I go down to the boat" might be after the compressor has locked, too late. They run all the time around here. It keeps the boat ready for occupancy, the electric is included with the awful slip rent, and the boat smells lots fresher all dried out with the AC running.......its strainer filled with marine life dating back to before the dinosaurs roamed the Earth. Little buggers bite like hell, too! Stuck in the strainers, they are in no mood to compromise....(c; No its not running. We turn everything except for the bilge pump off when we leave. Don W. > Don W <donw_s11atswbelldotnet@figure.it.out> wrote in news:6Dpxg.179658$F_ > 3.148605@newssvr29.news.prodigy.net: [quoted text clipped - 12 lines] > Little buggers bite like hell, too! Stuck in the strainers, they are in no > mood to compromise....(c; Don W <donw_s11atswbelldotnet@figure.it.out> wrote in news:LYexg.11933 $2v.9985@newssvr25.news.prodigy.net: > ;-) Actually, I'm considering doing something > worse, which is relocating the unit to somewhere [quoted text clipped - 3 lines] > > D Hmm....I'm not very "nautical". Tugboats and other commercial vessels did what I think is the right thing....scrap all this marine crap and put a Coleman RV rooftop AC on top of that leaky hatch over the main salon with the louvers pointed fore and aft. To hide it from the purists, have the canvas shop make you a Ships Wheel Cover or one with nautical-looking logos or flags or knots. It does make a dandy deck seat if the boom isn't swinging. Tell the curious it's the "safety box" on deck after you hide the Coleman logo in canvas...(c; I talked a fellow in a nice catamaran into scrapping his crappy, always clogged with something, marine AC and putting a Coleman on each pontoon. They like to froze to death because they had the thermostat too cool..(c; Rooftop air units have all the "heat loads" OUTSIDE the boat, not in the closet with the intake heating up and eating your Btus. Once you get the hot compressor, hot seawater evaporator and hot fan motor OUT of the air conditioned space, it takes a few thousand LESS Btu to cool the boat! I also like the RV units with "Easy Start" kits in them. INstead of that huge starting current blinking the lights, Easy Start units SLOWLY start the compressor, using no more power to start the compressor than to run it. No surge current, you can use a lot smaller genset to power it. Ok, this commercial is over. Just look at your current installation and see how many lockers, cupboards, storage spaces you'd regain hauling out all those nasty hoses, ducts, the unit itself. Oh, I forgot to mention the rooftop AC is 1/10th the NOISE inside the boat while you're sleeping! > Don W <donw_s11atswbelldotnet@figure.it.out> wrote in news:LYexg.11933 > $2v.9985@newssvr25.news.prodigy.net: [quoted text clipped - 35 lines] > Oh, I forgot to mention the rooftop AC is 1/10th the NOISE inside the > boat while you're sleeping! Yep, I've considered replacing this AC with an RV unit, and may yet do just that. The only place I could put it would be over the hatch in the V-Berth. We'll see... Don W. Don W <donw_s11atswbelldotnet@figure.it.out> wrote in news:vHqxg.179666$F_ 3.38636@newssvr29.news.prodigy.net: > Yep, I've considered replacing this AC with an RV > unit, and may yet do just that. The only place I > could put it would be over the hatch in the > V-Berth. We'll see... No hatch in that useless space under the centered boom? Sorry if you don't have one, there. That works great with the louvers pouring the cold fore and aft. It'd make a V-berth like a meat locker in 10 minutes while the galley sweated away aft.....not good when you're trying to coax the average cold-blooded female into the V-berth for a little R-n-R....(c; |
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