Marineaire Rebuild? Replace?

I have three Marineair units onboard. I believe 2 12,000btu's, salon and stateroom, and a 9,000 btu in the v-berth. To the best of my knowledge all three are original to the 1987 boat. I had them looked at a few months ago and was told:

1) The 9,000 up forward, putting out 1/2 cooled air, is "losing pressure between sides". Nothing they could do but they refilled coolant and it was better for a while.

2) The 12K in the salon had a slow leak out the valve. "The valve is located in the back and we can't service or replace it, have to pull the unit and you might as well get a new one as it is so old." refilled coolant, worked better.

3. The stateroom unit still works well on AC. Was told that pressure was fine and it was cooling normally. Issue with it is that when I do anything funky with the controls or electrical onboard while it is running it flips its main breaker. Not good.

All 3 have no working heat function. I believed it to be due to lack of use and the valves were stuck. I tried exercising them, tapping them, on/off, etc. and got to where I could hear the valve flipping but no real heat.

Sorry for the long details, my question is whether or not these old units can be pulled and rebuilt with any success or are they simply old and need replacement. Do they rebuild AC units or am I just wasting money trying it?

Thanks for comments.

I am in almost exactly your situation, with 2 x 16k, 1 x 12k and 1 x 10k units which when I bought my boat were all 1986 installed. A 16k failed first a few years back and was judged not worth repair due to extensive rust. The 10k cool only failed next and I replaced that with a used but newer reverse cycle model to have heat in the master stateroom it serves. The 12k in the VIP stateroom has just failed and needs a new compressor. These are readily available and not huge $, but gas and labor costs and the overall state of the unit means I've decided to replace with new. These units are very easy for an owner to uninstall and reinstall without specialist help and if you can wait for Defender or whoever to have one of their regular sales, at under $1700 (16k) it's not so painful. But once you involve specialist aircon techs repair costs quickly become prohibitive. If you want to explore a repair option, pull the unit yourself (it has to come out either way) and take it to a regular home ac place for evaluation. Remember to take the control panel with you too...they just unplug via a standard RJ cable.

Well, a few points:


To the OP: If you believe the advice you are getting, then replace them all. And maybe even if the advice is flawed, I would probably replace them as well as they are old, the reverse cycle doesn't work, etc. But replacing is not likely to solve your electrical problem.


For Aquebelle: I don't think you will save anything by taking the unit out and taking it to a home A/C place. I don't think that the average HVAC tech understands how to set the freon properly in a marine A/C unit. You usually have to empty it completely and then weigh the new freon to get the right amount.


But I agree that DIY replacement is very doable. It usually consists of just unbolting the main unit and ducts and putting another in its place and hooking up the wiring. Also replace the temp control unit with the one that comes with the new one, but as he notes it is usually a simple cable plug in.


David

firstbase said:

I have three Marineair units onboard. I believe 2 12,000btu's, salon and stateroom, and a 9,000 btu in the v-berth. To the best of my knowledge all three are original to the 1987 boat. I had them looked at a few months ago and was told:


Sorry for the long details, my question is whether or not these old units can be pulled and rebuilt with any success or are they simply old and need replacement. Do they rebuild AC units or am I just wasting money trying it?

Click to expand...

Marineaire... or Marine Airrrrrr (latter is now a Dometic thing)?

Might not matter, but we had two 16k BTU Marine Airrrrrr Vector Compact models, originally from 2002... and I just replaced both with the Dometic Turbo (which was named the Vector Turbo before Dometic acquired Marine Airrrr).

So far, so good; quieter, better airflow, improved drain pan, etc.

The original units were still working, but sometimes a little balky and getting really loud... and I reckoned I was close to having gotten my money's worth.

-Chris

New units use modern Freon replacement and are so much more efficient. Amperage from 1985 to today is cut in half. Re-building the old ones is like putting lipstick on a pig. I have Flagship marine units. They have heat coils. All the controls are common AC parts none over $25. No expensive circuit Boards. Use same thermostat as a house.

obthomas said:

New units use modern Freon replacement and are so much more efficient. Amperage from 1985 to today is cut in half. Re-building the old ones is like putting lipstick on a pig. I have Flagship marine units. They have heat coils. All the controls are common AC parts none over $25. No expensive circuit Boards. Use same thermostat as a house.

Click to expand...

Really!! I thought that the new replacements for Freon 12 and 22 are inherently less efficient. That is why F12 and 22 existed for so long. I have only seen maybe a 20% improvement in power draw per BTU of cooling over the years more due to more efficient motors, compressors and heat exchangers, not the refrigerant.


The first marine A/C unit I had was a 1990 Cruisair. It drew 15 amps to make 16,000 BTUs. Modern Dometic Cruisairs draw about 10 amps but you have to add another 2-3 for the raw water pump so that makes them overall about 20% more efficient.



David

The new refrigerants are less efficient when retrofitted into an older unit, as they often require different condenser or evaporator sizing to work at their best. In a system designed around the newer refrigerant those issues are mitigated.

rslifkin said:

The new refrigerants are less efficient when retrofitted into an older unit, as they often require different condenser or evaporator sizing to work at their best. In a system designed around the newer refrigerant those issues are mitigated.

Click to expand...

David

rslifkin said:

The new refrigerants are less efficient when retrofitted into an older unit, as they often require different condenser or evaporator sizing to work at their best. In a system designed around the newer refrigerant those issues are mitigated.

Click to expand...

I think this is exactly correct! And the power efficiencies new vs old are very, very minor: physics is physics. Start-up power demands can be mitigated by the use of products such as Dometic's 'Smart Start', but that's about it.

Any strong recommendations for replacement units? We'll be pulling and replacing two CruiseAir 16K units with heat pumps soon. Self contained and DIY-friendly would be preferred.

Airstream345 said:

Any strong recommendations for replacement units? We'll be pulling and replacing two CruiseAir 16K units with heat pumps soon. Self contained and DIY-friendly would be preferred.

Click to expand...

Lots of opinions on that topic here on TF! Many like smaller outfits like Mermaid, etc that use off-the-shelf parts that can be locally sourced. Depends what is most important to you. For me, I care a lot about noise levels...I want the quietest possible (self contained) units. So I'm going for the Dometic Turbo models with sound shield.

I replaced a 7 KBTU Dometic unit with a 10 KBTU Dometic Turbo Unit and find it quite quiet and effective. You can (and should in my opinion) buy one with their proprietary soft start device installed. I don't think they had that option when I bought my DTU so I installed a Micro-Air Easy Start. No more ka-thud when the compressor cycles form either it on the generator.

I just skimmed this thread, so I might well have missed some things, but a couple of notes:

1) The schrader (service) valves are a common cause of leaks in any AC system. This is especially true with age. There are removable caps with o-rings/gaskets inside that can seal them. They can be bought online, from Amazon, etc. If ever recharging a system -- install or replace the cap with a good one with a gasket/o-ring. Some systems have caps without o-rings/gaskets, in other cases the o-rings/gaskets have dried out/shrunk/dry-rotted/over-tightened-and-damaged and/or the cap is plastic and has stretched or shrunk and isn't keeping the cap tight on the valve. In any case, if recharging, it is worth replacing the cap with a good brass one with a seal. These valves aren't the only cause of leaks by any imagination and may not be the cause of a majority of problems -- but they are a very common cause of leaks.

2) Someone in thread said that one needs to empty an R-22 HVAC system and weigh the refrigerant to recharge it. This is most certainly not true (.) And, empty the unit to weight it requires vacuuming it down before recharging. Depending upon the unit it can be charged in place, without emptying, by one or more of a variety of techniques. For example, using a manufacturer's charging table calibrated to ambient temperature or temperature differences, or according to pressures and temps on suction and liquid lines (super heat or super cool methods). Or, one of my friends, an old timer HVAC-tech and plumber, by listening to the operation and feeling the lines (I didn't believe it, either, and still don't know how he does it -- but it has always squared with the gauges when I've checked him).

The upshot is that, if there is a leak in an older system that, I'd try (a) injecting a leak sealer, (b) recharging, and (c) capping the valves before doing anything major. If it works, you could get years more use from either the valve caps and/or the leak sealer. If not, you may still get days to months more use. And, even if it gets you nothing -- it was still a low cost nothing.

I've had remarkable luck getting old systems to keep working. They all die eventually. But, eventually can often (again, not always, and again, not necessarily mostly) be a season or several later.

I saw something in the thread about a bad reversing valve. First check the electrical, because it could just not be energized. After that, try tapping on it. If stuck after periods of non-use (not opening and closing), they can often be coerced into working again. Lastly, remember that a bad valve can mess with pressures and look like a compressor failure.

Just removed two 16K split units with compressors in ER. Installed a 16K, 12K and 6K Marineaire self contained units. The install required a bigger pump and running water to the three units. The big plus was eliminating the two large compressors and many feet of insulated Freon lines. Easy DIY job if your comfortable running the electrical for the units and the pump relay control box. About 5 boat bucks for the job.

My Marine Airrrr makes a racket. Clunks on and off and growls when running. Still heats and cools just fine. I don't use it a lot so will just wait until it dies. Thanks for the related info on it being a pretty easy "boat owner" swap. That's what I'll do when the time comes.

pete

We installed 2-16K Dometic Vector Turbo units. Full on cool they draw ~10.5 amps. Other than the wallet flush they’re great and would replace them with the same unit. They come with a plastic/fiberglass pan so no rust to deal with from the condensate. Another plus is the air duct pivots so you have more install options. The install was in 2008.

djmarchand said:

Well, a few points:


To the OP: If you believe the advice you are getting, then replace them all. And maybe even if the advice is flawed, I would probably replace them as well as they are old, the reverse cycle doesn't work, etc. But replacing is not likely to solve your electrical problem.


For Aquebelle: I don't think you will save anything by taking the unit out and taking it to a home A/C place. I don't think that the average HVAC tech understands how to set the freon properly in a marine A/C unit. You usually have to empty it completely and then weigh the new freon to get the right amount.


But I agree that DIY replacement is very doable. It usually consists of just unbolting the main unit and ducts and putting another in its place and hooking up the wiring. Also replace the temp control unit with the one that comes with the new one, but as he notes it is usually a simple cable plug in.


David

Click to expand...

I believe the advice was good but along the lines of most things these days. Nobody fixes anything any more, just replaces. Wasn't sure if they were rebuildable like a transmission or similar. My mind and wallet were set for replacement so I will most likely go that route. They are Marineair not Marinearrrrr. On the electrical issue, that has to be checked by an electrician and probably best to get that done prior to replacement. The question is whether I replace myself or pay for install. I keep reading comments about how easy they are to replace as long as electrical is good to go on wire size, breakers. I have old manual controls so will have to use a plate of somesort to cover the old openings in the teak woodwork. Luckily the ducting is very short and seems straight forward. "Seems" being the big word.

While it sounds like the decision has been made, here's more reason for upgrading. Part of the change from older units to newer one involves rotary compressors which are much more efficient and generally quieter. If you pay for metered electricity and use the unit a fair amount, this added efficiency starts to pay for itself in saved electric dollars. Secondly, if you run the units off your generator, in addition to saving fuel dollars, the generator runs under a reduced load, which is better for its life expectancy.

Ted

O C Diver said:

While it sounds like the decision has been made, here's more reason for upgrading. Part of the change from older units to newer one involves rotary compressors which are much more efficient and generally quieter. If you pay for metered electricity and use the unit a fair amount, this added efficiency starts to pay for itself in saved electric dollars. Secondly, if you run the units off your generator, in addition to saving fuel dollars, the generator runs under a reduced load, which is better for its life expectancy.

Ted

Click to expand...

Thanks Ted. Sitting here thinking about it and while I have been leaning towards replacing all three it might not be a bad idea for me to pull the salon unit, the one I was told had the leaky valve, and take it in for review. The stateroom unit works well and, assuming the circuit breaker flipping is no big deal, can stay until it gives up the ghost. The one up front I honestly don't care too much about as we never have anyone staying up there. It does cool somewhat but I wouldn't want guests using it for cooling in a Florida summer. Also, summer is almost gone so I have the winter to see what is what. If I am missing AC for a while it doesn't put a hurt on anything. Pulling one at an opportune time lets me educate myself on what is what without the stress of having it out during 92 degree heat. Right now I have one RW pump handling all three units. Hopefully I wouldn't have to change that as well if I replace them all at some point. Not sure what GPM it is.

Assuming yours are not split units, I would replace them with new. Quieter, more efficient, no pan rust. Since u already have power, ducts, raw water & condensate, should be a straight forward DIY job depending on new control wiring. (Measure everything before u buy the new unit).

"Lots of opinions on that topic here on TF! Many like smaller outfits like Mermaid, etc that use off-the-shelf parts that can be locally sourced."

This would be a huge concern for cruisers that may need repairs in less developed areas.

Carib , Mexico, Central America, Nova Scotia, etc.

In the USA most parts should be off the shelf , in even small towns.

One day repair , instead of Fed EX, and specialist.

KISS

Airstream345 said:

Any strong recommendations for replacement units? We'll be pulling and replacing two CruiseAir 16K units with heat pumps soon. Self contained and DIY-friendly would be preferred.

Click to expand...

This season, we replaced our original 16K BTU Marine Airrrr Vector Compact units with 16K BTU Dometic Turbo (DTX) units, without the sound shields (yet?), and so far, so good.... quieter compressor, better airflow, improved drain pan, better mounting stand-offs, etc.

But that's very limited experience. OTOH, part of the reason I chose those, aside from the drop-in one-for-one easy replacement, is because of recommendations from several other folks in our owners club, apparently all good.

Our installer told me the sound shield can be fitted after-the-fact, and also made it sound like it's an expensive option (?) and my wallet is suffering from several projects anyway.... so I'm still thinking about it...

-Chris

djmarchand said:

Really!! I thought that the new replacements for Freon 12 and 22 are inherently less efficient. That is why F12 and 22 existed for so long. I have only seen maybe a 20% improvement in power draw per BTU of cooling over the years more due to more efficient motors, compressors and heat exchangers, not the refrigerant.


The first marine A/C unit I had was a 1990 Cruisair. It drew 15 amps to make 16,000 BTUs. Modern Dometic Cruisairs draw about 10 amps but you have to add another 2-3 for the raw water pump so that makes them overall about 20% more efficient.



David

Click to expand...

Geez... I meant my contribution to be......my new units use modern refrigerants and my new units use substantially less electricity.

My rule of thumb on AC units in general, at 15-20 years replace if you start having issues, the cost of labor quickly will eat you alive, and you still have a marginal unit vice newer designs that are quieter and more efficient. Regarding freon, backfit compatible versions loose about 15-20% thermal efficiency, new units are designed to handle the higher evaporator pressures required for the same BTU load using newer freons.

"My rule of thumb on AC units in general, at 15-20 years replace if you start having issues"

The question then becomes replace with a bit more modern unit or finally go to a modern mini-split setup?

On a boat that requires cabin heat at times the mini split would have huge advantages.

Especially with metered electric, and no winterizing requirements.

FF said:

The question then becomes replace with a bit more modern unit or finally go to a modern mini-split setup?

Click to expand...

Huh? A modern mini-split setup? No, please don't do this to me.

My three self contained units fit nicely out of the way and take up no real usable space. My heat needs are to take a chill off not heat up in freezing, or close to it, weather. My engine room is tight to say the least. What is the advantage to a mini-split setup?

"What is the advantage to a mini-split setup?"

A single variable speed compressor uses less juice at lower loads ,almost silent and no water pumps or winterizing.

In heat mode it is 300% to 500% more efficient than a resistance wire.

Zones are easy. Smaller units are pre charged so DIY install is easy.

I would stick with Mitsubishy , if parts or repair is ever needed they will still be in business.

FF said:

"What is the advantage to a mini-split setup?"

A single variable speed compressor uses less juice at lower loads ,almost silent and no water pumps or winterizing.

In heat mode it is 300% to 500% more efficient than a resistance wire.

Zones are easy. Smaller units are pre charged so DIY install is easy.

I would stick with Mitsubishy , if parts or repair is ever needed they will still be in business.

Click to expand...

Thanks FF. For some reason I thought that a "mini-split" was possibly a new(er) type of unit rather than just a small split system. Am familiar with, never owned, a split setup. Just can't take the thought of finding space in my engine room for the second half of the equation. Plus...the necessary replumbing of things. My boat list is a mile long as it is!

Do yourself a favor, replace. I replaced mine. The old saying, “penny wise and pound foolish”.

"Just can't take the thought of finding space in my engine room for the second half of the equation."


No space in the engine room need be used , the compressor is mounted out side , or some times simply hung from the aft rail. The compressor etc move heat from outside in , or get rid of heat while air cond.


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