Air Conditioner

quote:
Originally posted by rawidman

I am having second thoughts about the resistance heat option. My previous AC would often begin to freeze up when it couldn't keep up with the heat load (a trawler with lots of windows). The system would go into heat mode for a minute or two and melt the ice, then back into cooling mode. A non reverse cycle AC won't be able to do this. I'm going to ask the company about this before I order.

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Not sure I understand how reverse cycle defrost mode and a resistance heat capability would affect each other?

I don't know too much about it, but I do have the model numbers (somewhere) for the installation one of or dock neighbors had done just prior to last winter. They replaced their ancient reverse cycle system with a new one Vector Turbo something or other), and then at the same time added the resistance unit. The basic reverse cycle system does what it does. The resistance heat mode comes on when they want it, aided by the blower from the reverse cycle unit.

During the winter (they're liveaboards, now), they close the sea cock, and use the resistance thing, so only the blower from the reverse cycle system is active.

-Chris
 
"Reverse cycle" is a heat pump. It serves as an air conditioner in the warm weather and by reversing itself, provides heat in cold weather. As the water temperature becomes lower, the heat function becomes less efficient and as the water temperature goes below 40 degrees it's nearly useless. At warmer water temperatures, reverse cycle heating uses less electricity than resistance heating. This doesn't really matter to me, I pay a flat fee for electricity.

The unit I am looking at has resistance heat but no reverse cycle capability. Other than the heating elements, it only cools (or blows air). Thus the concern over how to thaw the coil if it does freeze up.
 
quote:
Originally posted by rawidman

"Reverse cycle" is a heat pump. It serves as an air conditioner in the warm weather and by reversing itself, provides heat in cold weather. As the water temperature becomes lower, the heat function becomes less efficient and as the water temperature goes below 40 degrees it's nearly useless. At warmer water temperatures, reverse cycle heating uses less electricity than resistance heating. This doesn't really matter to me, I pay a flat fee for electricity.

The unit I am looking at has resistance heat but no reverse cycle capability. Other than the heating elements, it only cools (or blows air). Thus the concern over how to thaw the coil if it does freeze up.

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Yep, I understand the whole heat pump thing.

FWIW, the units our dock neighbors have apparently have all that sorted out. The reverse cycle part (water pump, condenser, etc.) doesn't need to run when their resistance unit is working. Or they can use the resistance unit to augment heat from the reverse cycle system.

During the winter, they close the thru-hull... and only the blower from the reverse cycle unit works to force resistance heat through the ducting. No concern about freezing, thawing coils, etc.

-Chris
 
Update and another question:

OK, Flagship makes a good case for it's quality and warrantee and it's available with resistance heat. I haven't found anything close.

But: It only has two discharge options, top and left (looking at it from the return air intake (or filter). I need right discharge. The sales guy said "no problem, just turn it around 180 degrees. We do it all the time.". That means the return air would come into the compartment under the seat, move around and above the unit and then enter the unit. I told him I would have to think about it.

While less than ideal, it seems this would work. There's plenty of room in the compartment.

Thoughts?
 
I've installed several without regard to inlet air path. No problems at all.
 
quote:
Originally posted by rbmitchell

I've installed several without regard to inlet air path. No problems at all.

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Thanks, I think I'm going to go ahead and do that. I might have to wire it before I put it in place but based on their instructions and you're post, it's probably the best plan for me.
 
quote:
Originally posted by rawidman

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only two sources of this failure;

1 the heat exchanger had a bad joint or section of tubing inside it. pretty unlikely there are any silver soldier connections inside the water passages.

2 there is an electrolysis issue on the boat and a galvanic survey is indicated. this is much more likely and should be done to rule this out as soon as the new unit is installed so the process does not repeat.

before removing the old unit it may be worth while to find out if the bond on the unit is working completely. if you are unsure of any of this, it would be best to get a marine electrician involved who can perform the galvanic survey. trying to solve a bonding issue(s) without doing a complete survey is probably going to lead to excessive swearing. a faulty bond on the existing A/C unit may not be the only source of the problem.
 
quote:
Originally posted by rawidman

Update and another question:

OK, Flagship makes a good case for it's quality and warrantee and it's available with resistance heat. I haven't found anything close.

But: It only has two discharge options, top and left (looking at it from the return air intake (or filter). I need right discharge. The sales guy said "no problem, just turn it around 180 degrees. We do it all the time.". That means the return air would come into the compartment under the seat, move around and above the unit and then enter the unit. I told him I would have to think about it.

While less than ideal, it seems this would work. There's plenty of room in the compartment.

Thoughts?

Click to expand...


Can't give you any expert advice, but I plan to install AC on my Carver this spring. I'm in Stuart at the moment and visited Flagship yesterday. I was impressed. Their units are old school with some desirable (IMO) features. No circuit boards- they use relays that can be replaced from virtually any source (the rep specifically mentioned Grainger), and no complicated thermostat. According to them, any 4-wire thermostat can be used if theirs fails. I saw the guys building the units (it's a small
operation) and everything looks real beefy. Nice bunch- they seem to be proud of what they make.

They printed off all the literature I need, and worked up a price quote for a 12K BTU unit (I'm guessing at capacity right now) with electric heat and deluxe install kit- $2200. plus shipping. I asked about certified installers. They don't have any - most of their units are installed by DIY'ers, and they're ready to help with advice and support including sizing the unit properly. I think I'm sold.

You can call Chris Treppler (Production Mgr) at 772-283-1609 if you have any questions.
 
Only issue with reversing the unit is access to the filter once unit is installed. if ur flipping it around i assume the filter is going to be the furthest point from u . Just make sure u can reach it. Also the condensate drain pan my not have fittings on all 4 sides . make sure the drain is still accessible with out too many elbows.

Rob

PS i would really look into the bonding system on the boat. Something is attacking the copper . Coils don't fail and u had two consequtive failures. I dont believe in coincidences
 
I bought a flagship unit off eBay about 10 years ago. It was a remanufactured unit with full warranty. In about 6 months the compressor went bad. They stood behind it and replaced it at no charge. I did have to take it back to the factory so I did have to drive to Stuart drop it off and pick it up a week later ( or I could have shipped it) but was very happy with thier service. The unit is still working fine although I don't have the boat anymore.

It had the electric heat that I only turned on to see if it worked . Never had use for it here in Fort Lauderdale.
Also if I remember right there was a relay that shut off the compressor if the unit iced up and the fan ran and melted the ice. Don't rember it ever icing up though just rember reading that in the owners manual.

Just ordered a remanufacted Ocean Breeze AC off eBay to replace my old marine air. Should get it tomorrow and I will know how it works this weekend.

Rawidman , A 16,700 btu remanufactured unit from Ocean Breeze AC full one year warranty for 980 plus shipping. Mine will be here tomorrow.
 
Well, it's bought, shipped and installed. I had a little trouble getting it into the space but nothing a sabre saw couldn't fix. The filter is on the return air vent, not the actual unit so replacing it is not a problem. I had to extend two hoses but again, not a problem. The heat works fine and so far it hasn't tripped the breaker so I'm assuming the heat and water heater are sharing the 30 amp service fine. I tested the AC function and it works but it's too cool to actually use it here.

I'm going to assume the ground wire from the electrical system is "bonding" the unit but I can check one of these days. Perhaps since the installer removed the control box from the previous unit and mounted it separately that interrupted the bonding of the actual AC chassis. It's a little late to worry about that now.

John, Chris was my contact person.
 
Is the return air vent duct directly to the unit and sealed air tight? If not it should be. And also if not you'll still need a filter on the unit itself.
 
Bill beat me to it . Always try and have a filter on the unit, it cant hurt. Just dont forget its there . I have never seen an air tight return plenum on a boat .

Rob
 
quote:
Originally posted by Robski97

I have never seen an air tight return plenum on a boat .

Rob

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And that is why I make my own. :-)

Most boat builder should not be allowed to install their own A/C systems. They apparently haven't a clue on how A/C works.
 
Just curious, do these AC systems utilize pencil anodes in the RW side of the h. exchsnger?
 
quote:
Originally posted by Capt. Bill1

Is the return air vent duct directly to the unit and sealed air tight? If not it should be. And also if not you'll still need a filter on the unit itself.

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No. The manufacturer told me it would be fine as long as air could get to the unit.

So - the unit is installed beneath a lounge seat (imagine a box) , sealed except for the return air vent (with filter). The return air flows around and then into the unit.
 
As long as there is absolutely no way the unit can get air from anywhere else it should work. But if there is any way at all for it to pull air through any cracks or gaps it will. And in that case I'd keep a filter on the front of the coil fins themselves as well.
 
I have one of the separate heat units made by Cruise-Air (HMDL2-7). It's brand new. The heating elements draw 2000 watts at 110VAC.
If someone needs it contact me.
Bill
 
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