Best reverse cycle heat / airconditioner

[Dockhead]

Originally Posted by colemj

. . .
However, there is a limit. Heating only works to water temps ~45*. Below that, there is not enough differential to provide sufficient heat. . . .

Trivial technical point -- although obviously efficiency falls with more temperature difference, it's not the temperature difference which is the main limiting factor for reverse cycle heat on boats, it's icing of the coils. Many air source heat pumps work efficiently at temperatures well below freezing. They also suffer from icing problems, but their coils, unlike water-source heat pumps, can be easily defrosted.

[Garrettw]

Originally Posted by ErBrown

I did initially wish the fan would kick of when temp is reached, but have since decided I like the air movement. That and a few fans means we can actually keep the boat boat comfortable during the day and downright cold (if desired) at night.

This is actually a programmable feature on the Cruisair stand alone units. You can set them to turn the fan on only with the compressor if you wish. It is program function 7 I believe and needs to be changed from "C" to "I". You can also adjust the low fan speed slower to control noise using function 5.


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[Garrettw]

Originally Posted by s/v Beth

Interesting bird, these heat pumps. Have they perfected them well enough to make sense enough to install in a world travelling cruiser? I will brave greenlands bergs to equador's isles. Will it really help or just be another thing that breaks down.

If you are in cold water climates, some units, like the Cruisair standalone we are discussing here, have an optional electric heater add on. These resistive heaters will automatically take over when the water temp is sensed to be below 4C (40F). They also have an interesting feature where the electric heat will run with the compressor pulsing in cool mode which serves to both heat and dehumidify the boat. This is not as efficient as a fuel fired heater, as one will need an extra step (genset) and that adds another inefficiency to the energy chain. But it does give you viable heat and air conditioning that will basically work anywhere, all in a single package.


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[Cap Erict3]

Originally Posted by s/v Beth

Interesting bird, these heat pumps. Have they perfected them well enough to make sense enough to install in a world travelling cruiser? I will brave greenlands bergs to equador's isles. Will it really help or just be another thing that breaks down.

I have not seen one that didn't require added heating elements in cold climes.


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Looking for another pretty place to work on the boat.

[ranger58sb]

Originally Posted by a64pilot

Any idea where I can buy a Dometic turbo 16K BTU?

I can't seem to find many sources online, seem to be mostly dealers who are more set up to do installs?

One of our members got new ones from Annapolis Cruisair and he said he got great prices. But then he had them do the install, too, I think...

Made me think at the time, though, that maybe the dealers can fix you up at OK prices, but just don't advertise it that much.


Edit: Nope just checked archives.... he did the install himself, just ordered the unit from the Annapolis Cruisair folks. Said it was an easy install, direct replacement for the original. Couldn't quickly find what (if) he said he paid... Still, given he seemed pleased with the price, could be that dealers can quote you something better than what you're seeing online. He probably saved some shipping money by picking the thing up himself, so maybe another key is to check your nearby dealers...

-Chris

[a64pilot]

I'll keep looking, if I can find a good price I'll order the Dometic / turbo.
Is it just the Cruiseair that you can program the fan? I'd suspect all units are identical except for stickers, but sometimes I guess programming changes with name

Just myself heat isn't an issue, if the water temp is below 40, I'm not there.

I learned in Bosnia and Korea that I am allergic to cold

[svHyLyte]

For what its worth, you might also consider the units made by (click on) King Air. We have had King Air equipment since 1996 that has performed admirably. In 2012 we finally had to replace the 16K BTU reverse cycle unit in our salon after our 16 year old unit finally gave up the ghost. The King Air heats, cools, has an "automatic" mode where it will either heat or cool the yacht as necessary to maintain a specific pre-set temperature; and, an "Away" mode in which the fan unit operates at very low speed but periodically speeds up, kicks the compressor into operation, and runs for an 30 minutes or so in that mode to knock down the humidity on the boat and then reverts to very low speed fan operation for 4-5 hours before repeating the cycle. Best, King Air has given us exceptional post sale service, even after the warranty period, on the rare occasions when we've needed it. And, the units are quite simple "plug'n play" so an owner installation, particularly in a boat previously fitted with AC is a no brainer.

FWIW.

[a64pilot]

Just called the King Air people., interesting, US manufactured out of all US Parts, except the blower.
I can't find any real data on the thermostat though, he seemed to indicate that upon reaching set point the fan cycles off, just like a house, which means of course the temp sense device is not in the air return side of the unit, but in the thermostat, like a house one is.
HyLyte, can you confirm the unit completely shuts off when temp set point is reached?

Anyone have a picture or info on the thermostat?

BTW, they are real expensive, number I got was about $2,500 + shipping.

[ranger58sb]

Originally Posted by a64pilot

I'll keep looking, if I can find a good price I'll order the Dometic / turbo.
Is it just the Cruiseair that you can program the fan? I'd suspect all units are identical except for stickers, but sometimes I guess programming changes with name

I think there came a time when Marine Air and Cruisair units became pretty much the same. Ours says Marine Air Vector Compact, but I think there's a Cruisair Vector Compact and it's the same unit. That might have happened as Dometic acquired companies.

Then eventually Dometic seems to have consolidated info on all their stuff into the main Dometic website...

The Passport, Passport II, and Elite control units on either Marine Air or Cruisair ACs allow programming. We have the Vector Compact P (VCP) model AC unit with Passport II controllers from circa 1998 rev A17 (ours is a 2002 model, rev A26); I don't know much about what the differences might be... although the Elite units are newer, so if there are more features to be had, they'd be the controllers that have 'em. The temp sensor is in the Passport display panel.


(The Vector Compact M (VCM) model AC has a mechanical controller with round knobs; not sure where the temp sensor lives. From the pic, it doesn't look programmable.)

Dometic's website has the manuals and the programming instructions. Pretty easy.

-Chris

[KadeyKrogen38]

I have used King Air, out of Florida for about 29 years. They make a 19000 BTU unit with the same footprint as the 16000 BTU models. Their pans are stainless steel. They are very cooperative and supportive. They even custom built/modified foot print to fit my space at no added charge. My first unit from King lasted 17 years running almost year round (Houston). The new unit has very good digital controls. Link - Marine Air Conditioning Systems, A/C from King-Air, Cooling the World since 1947

[a64pilot]

Actually the pans are 5,000 series aluminum, which is a weldable aluminum.
I can see how that would look like stainless, and the aluminum ought to be as good as stainless in this application, and lighter too. Ought to be nothing but clean pretty pure water and a little dust in the pan and that shouldn't be too corrosive

Do you have any info on the controll?


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[Colin A]

I was on a boat a couple years ago in January in Tenn. It was a large motor yacht with 3-4 Reverse AC units. Air temp was in the teens (6F in the morning) And the water was freezing on the edge of the lake/river but the systems did manage to take the chill out of the air enough that I could wear a sweatshirt and be somewhat comfortable working on the boat. There were actual icicles forming on the AC outlet but it never froze over completely. The owner told me he left it in year round unwinterized and ran the heat constantly to keep things from freezing.

[HopCar]

A64, I just quoted a guy I know from the trawler forum on a Vector 16K.
I don't sell many air conditioners so I may be expensive. Can't hurt to send you the quote. I'll PM it to you.

[a64pilot]

Originally Posted by HopCar

A64, I just quoted a guy I know from the trawler forum on a Vector 16K.
I don't sell many air conditioners so I may be expensive. Can't hurt to send you the quote. I'll PM it to you.

I'd appreciate that, I didn't even think of you for an AC, I guess I should have seeing as how I have bought chart plotters, Radars and lots of other stuff from you.

Sorry about that.

[svHyLyte]

Originally Posted by a64pilot

Just called the King Air people., interesting, US manufactured out of all US Parts, except the blower.
I can't find any real data on the thermostat though, he seemed to indicate that upon reaching set point the fan cycles off, just like a house, which means of course the temp sense device is not in the air return side of the unit, but in the thermostat, like a house one is.
HyLyte, can you confirm the unit completely shuts off when temp set point is reached?

Anyone have a picture or info on the thermostat?

BTW, they are real expensive, number I got was about $2,500 + shipping.

The thermostat is solid state and is situated in the control module which can be positioned anywhere conveniently reached/observed. The control module is an approximately 3.5" square by 1/2" deep unit that connects to the AC unit with small cable that looks a bit like a telephone cable. (I will take a snap of ours when I'm on the yacht tomorrow and post it for you.) The fan speed is variable and dependent upon the temperature. As the air temperature on the yacht approaches the user's set-point temperature, the fan speed slows. The speed range of the fan, maximum/minimum, can be specified by the user. We have ours set such that once the set-point temperature is reached, the fan slows to about 30 RPM, just enough to keep air circulating but so slow that one cannot hear the fan at all (or at least I can't). In heating mode, the fan speed control reverses. When the temperature is very low, one wants the air speed low such that the air has enough time in contact with the heat exchanger to warm/heat up so as to disburse heat through the cabin efficiently. As the air temperature increases, the fan speed does also to keep the air moving. It is a very effective arrangement.

FWIW...