Cruise air ac/heating

I have 3 Cruise air Units on my boat. Two are new (less than 2 years) and one is I'm sure, original 20+ years. The two new ones ice/freeze up within 5 minutes while the old unit just keeps on chugging along extracting heat from the water.
The older unit is 6K, the new are 12K & 6 k respectively. Having a problem understanding why old one makes heat from 36* lake water and the new ones freeze up. Any suggestions ?

Thanks

 

The idiotic efficiency police have got you. The good news is that the units that don't work might draw about 10% less current than the one that does. Unless they run longer, then they don't. There are a couple stubborn mfgs that refuse to make heatpumps that don't work. I just installed one in a little cabin that we are trying to make serviceable year round and I was quite pleased to find it pulled like a champ down to 8 degrees. Interior held at the set point of 62 and it was cycling normally. I had a running battle with code enforcement in Florida trying to keep a somewhat unusual hotel chilled. $750/night rooms and we couldn't install a decent AC? I eventually installed a 1.5 ton ac, and about 3 tons of dehumidification, which didn't count.

You may be able to adjust the performance of the heat pumps by seasonally adjusting the refrigerant load by a couple ounces. It helps if you are an ac tech and can buy the stuff. Or know one. No, you shouldn't have to do this, but it can sometimes extend the practical temperature range by several degrees.

<edit> Have you checked the voltage to the units. Are they getting good clean power. Power factor?

 

Thanks Phil. I suspected as much. The new super efficient units extract too much heat from cold water and turn it into ice. Clamp on amp meter says the units are receiving 14.6-15 A at unit. Power Factor ? Not sure I understand. The old unit ( V berth keeps it above freezing inside boat and the extreme heater is in engine compartment. Knowing Tenn summer, we'll most likely be glad for extra cooling power . Thanks again

 

I may have misunderstood you. In fact I did. I misread your post. You are running water to air systems. So you are slushing up the heat source water? What you need to do is increase the refrigerant pressure in the entire system so that the cool side stays above 32 degrees. Try blocking off 80% of the ducts to the units that freeze up until the cabin temp gets up to 65 degrees, then start letting more air flow happen as the cabin continues to get warmer. Sorry for the previous rant. Let us know how it works. Make sure nothing is restricting the water supply.

By power factor, I mean the phase relation between voltage and current, which most cheap multimeters won't read. It can effect compressor performance, but I don't think that has anything to do with your problem now that I've got my head on straight.

 

My own split unit cruisair ancient model does not freeze up.
In very cold 35* water I can get 70* air inside the boat. I think the air coming out vents was mid 80's on a very cold day.

My system lost its r22 charge and I recharged 2 years ago with a propane-butane mix.
It heats fine and it cools ok. But I think the cooling may not be as cold as with R22.
For example, if I run the system with evaporator fan off, (did as a test), evaporator will not ice up, it stays very cold. I assume something to do with too much butane not enough propane. Might want to increase the propane percentages.

I did add a nice big drier filter in the line running into the compressor after the valve.

The compressor draws only 10-11 amps now and this is a 16,000 btu unit.