A/C on a 32

[phild]

FYI - You may be better off with the unit you have! The following admittedly somewhat bias comparison of resistive vs. reverse cycle units is excerpted from Flagship's web site! This is not meant as an endorsement of either system just food for thought!

FLAGSHIP COMPARISON FOLLOWS:

The two typical means of producing heat in marine HVAC units are resistive electric and reverse cycle. Although we can and have manufactured both types, we normally stock and sell the resistive electric for many different reasons which we will outline on this page. With a reverse cycle heating system, a reversing valve reverses the flow of refrigerant, making the condenser an evaporator and the evaporator a condenser. We will outline the benefits of each system for your consideration.

BENEFITS OF REVERSE CYCLE HEAT:

Reverse cycle systems are a more efficient means of producing heat when compared to resistive electric heat. In marine applications if you are a live aboard with metered electric and have a water temperature in the heating season that is always above about 45-50°F, reverse cycle heat may be right for you.

BENEFITS OF ELECTRIC RESISTIVE HEAT:

Extended component life. You are not using the compressor and raw water pump for heat. The only moving part is the blower. Electric heat units will work ANYWHERE - not dependent on water temperature. Reverse cycle heat will not work with a raw water temperature below about 45-50°F and the compressor is stressed near these temperatures. The standard 2KW element we have on our 16,500 BTU units are presently used on the Canadian Coast Guard 47' survival craft, and have heated the USCG 47'MLB for the past six years from Alaska, The Great Lakes and Maine to the Gulf Coast and Virgin Islands.

You may winterize your cooling system and close your through hull ball valve. No raw water is needed for electric heat therefore you will not have the hazard of an open through hull fitting that may freeze in a power shortage and possibly sink your boat.

The elements are in line with the air flow and create negligible back pressure. Never restrict the suction side of a centrifugal blower or pump, conversely you may restrict the discharge side with relative impunity. Our low temperature elements are safely mounted inside the discharge throat of the blower motor, only a fraction of an inch away from the squirrel cage - it never gets red hot, and therefore doesn't "burn" the air.

Three "fail safe" temperature limit switches are within inches of this element, making our time proven system the safest available. We have thousands of these units in service for many years!

A "straight cool" marine A/C with electric heat is much more simple and trouble free.There is no need for a reversing valve that is notorious for sticking, and no need for a heat pump thermostat, or the extra relay, refrigerant tubing and wiring to operate this system. You will be able to heat your boat even in dry dock.

Electric heat is more quiet than the reverse cycle heat, especially if a piston compressor is used. The condenser in a reverse cycle unit in the heat mode will get very cold and possibly develop ice and sweat. This is why most reverse cycle units have the condensers in the horizontal position so that they will not drip on the blower motor, and why most reverse cycle units have a full wet drain pan. Our condensers never get cold and can therefore be mounted vertically, over the blower motor. Our drain pan need only be under the evaporator, making the likelihood of condensate splashing out of the pan in a heavy sea unlikely and keeping the components dry.

Flagship's incredibly safe, effective and reliable heating systems have been heating the US and Canadian Coast Guard's survival craft for several years in the most extreme and demanding environmental conditions imaginable - from Alaska, the Great Lakes and Maine, to the Caribbean and the Gulf of Mexico, since 1995.

We have thousands of these heating elements in service for many years - they are designed to last decades, not years!

[amytom]

A good read. Thanks!! Maybe time to wire up another shore power cable?

[Lady of the Lake]

Are you sure? Something just doesn't sound right about that. Did you read my earlier post (end of page 2)?

[amytom]

I will hold off for a while, still warm down here. Maybe when it gets cold the little warmth coming out will feel better. Also, I still need to seal up the plenum.

BTW. The Lady looks good with her new bottom paint; did you remove weight or paint higher?

[Lady of the Lake]

Brought the paint up a bit since I was getting nasty slime marks on the "away from the sun" side of the boat.

[Lady of the Lake]

OK, now I get it. I have the 16K BTU unit that has 1 heating element. Your 20K BTU unit has 2 heating elements. Since they draw more than 30 amps when run simultaneously, they need either 2 - 30 amp circuits or a single 50 amp. I see. So I went to the boat and turned on the heater and measured the current draw of my system with the single heating element and it draws just over 16 amps. A bit more than the 12 amps required for air conditioning. So AC will run with the EU2000 but heat will not. Bummer.

[amytom]

Hmmmm leads into another expensive and heavy idea. Are there any reliable, inexpensive, built-in, water cooled, gas generators in the 4KW range?

[Cat Tales]

A possible solution is a Westerbeke - www.westerbeke.com - which makes a 3kW and a 5kW with a SafeCO feature. They both run at low RPMs, 1800 or 2200.

[Lady of the Lake]

Or a pair of EU2000s with the cable that joins them together, although you probably need two separate since you will have two 30 amp circuits.

[amytom]

I would only run one circuit on the hook. I have a Yamaha 2400 generator that isn't being used. While it is heavy and awkward in it's frame I wonder if I could "rebuild" it into the aft nacelle with the exhaust going overboard (under bridge deck) and the fuel coming directly from the main tank.
A few concerns:
safety standards- fuel and exhaust in the aft nacelle near the steering arm
Vibration- have to build in a vibration dampening mount so I can sleep at night
Weight- the unit weighs about 70 pounds. without frame and fuel tank may still be 50 pounds
Cooling and aspiration- need to increase ventilation in the area. Maybe nicro solar fans?


Also, do I really want to mess with it? Or do I just want to go for a sail?

[Page 83]

I have a similar delimma on my 36. I have an elderly 13,000 BTU A/C and a 5kw generator that weighs (with tank, sound shield and plumbing) as much as 700 pounds, and it is the sole occupant of the port aft 'stateroom'. I've been trying to find a deal on the Westerbeke 3kw which I think will tuck under the port afterdeck. I've also looked at permanently installing an aircooled gen like the Yamaha or a pair of Honda Eu2000's, and the issue is not so much piping the exhaust overboard as it is pumping enough cool air thru the air-cooling. I did see a neatly done install of an Eu1000, involving a 1/2" cast iron exhaust pipe in a 4" cooling air exhaust, but I haven't heard any results. Do many people just store the hondas, and lift them out into the cockpit to run at night?

[amytom]

I have always set it on top of the fuel locker aft of the cockpit. On a 32 this is right above the cabin though and the noise goes right through to keep you awake, even with the "Ultra Quiet" Honda

[Cat Tales]

Sandy,

We keep our Honda EU2000 in the aft cockpit locker when not being used, putting it by the swim steps when in use. If you are considering the Westerbeke 3kW, check into the SAFE CO model. Westerbeke says that it is brand new and many distributors don't have it yet.

[thinwater]

I had one of those on my Stiletto 27. I liked the fishfinder aspect because the display is much better than just a number, and the transom transducer worked well... unless I was going over 5kts. It was iffy from 5-8 and useless above that. I had 2 different models, and regardless of angle, this was the best I could do. Still, it was good when slowed down and scouting anchorages.

The primary reason I mounted the 2nd one was that I was writing a book ("Circumnavigating the Delmarva Peninsula - A Guide for the Shoal Draft Sailor" available at www.alibris.com) and I wanted to scout inlets and anchorages that are simply not on NOAA's priorety list. I wanted to make some of my own charts.

There is always an upside; because of the speed limitations (~6.5 kts was good) I had to keep my speed down, and running the inner passages took longer. The wilderness from Cape Charles to Wachapreage is a beautiful place. If you are on the East Coast you've got to check it out.

[maxicrom]

Amytom,

Sorry that I was out of pocket during this adventure - we have PDQ 36 and are using a Mermaid 16K reverse cycle and it works great (rarely for heat as you will see). I'm a firm believer in a 30A system that never get's close to a 30A load. On startup the Mermaid draws about 12 - 14A (probably a bit much for the Honda) - but then quickly drops to 10A (sometimes a little lower). We are in DC and live aboard 4 - 5 days a week (year round) In winter we use 4 eHeat panels (2 small aft, 2 standard Fwd) on the outboard cabin walls. We mounted them on 1/2" plywood about an inch larger around than the panels - the forward panels are not even mounted we left them a little longer on one side so edge goes behind the closets and they lean in place. The Mermaid is noisy and cycles on an off blowing cold everytime it starts once the water chills (in a few more weeks for us) the 4 eHeat units are completely safe and keep the boat cozy (we have no concerns leaving the boat with them on). All 4 panels draw about 11A total the same as a singel space heater. On really cold night 20 degrees and lower we might kick on the propane heater as a booster. (http://www.eheat.com is the website). As soon as it warms up we remove the panels and are good to go - if it chills down we can use the Mermaid or propane heat. With the load from the coils this may be a way to go and in Fla you may not need 4 panels. They are similar to a piece of sheetrock and mount about 3/4" away from the wall (or plywood backing in our case) - I would say they take up maybe 2" max wall space and provide dry radiant heat - I think they are about $70 with a discount for more than 1.

Back to the Mermaid unit - we shared our head water intake and have not had any problems going on 4 years now - we are in fresh water much of the time though. As for power we had an available 110v breaker on our panel. For the panels we just plug them into regular outlets, we've added an outlet in the master FWD cabin. Where the cords are too short I've made short 12G (basically 5 ft orange extension cords) which work fine the eHeat panels come with 14G lamp cable.

Running on the Honda - I'm not sure if Honda has anything like this - but the Panda diesel units have a optional capacitor pack to allow them to support higher startup loads for short terms - the other solution would be to go to a smart Inverter system that makes up the amperage from your batteries allowing you to maintain while running a smaller generator.

Good luck,

Mike

Chilly Wed morning update - last night was windy and it dropped to 26 degrees (not gaining much today), we switched over to reverse cycle for the night switching back to the panels this morning. In this type of weather they will hold the temp to about 65 during the day. This time of year we miss our old cozy wooden ketch - thank goodness it's only a few months.