Marine Air - Air Conditioner - Recharge?

[jlombardo]

Does anyone have experience with recharging a Marine Air air conditioner? Is this owner manageable? I try to do as much work as possible on my boat.
Appreciate any advice/information.

Thanks,
John

 

[Bmarler]

No experience with that brand specifically, but if you have the tools and understanding of how refrigeration works, it’s completely doable.
If it’s simply low on refrigerant but still holding pressure it’s fairly simple to add some, but if it’s empty, you’ll need to vacuum the system. not rocket science, but you do need to know the procedure.

 

[Bmarler]

I should add, you should ask yourself the question of where did the refrigerant go? That usually means there’s a leak.

 

[jlombardo]

I agree, but it seems to have taken a few years so hoping that it's a product of time. The units are 25 years old. Am I mistaken or do they now sell convenient kits to charge systems?

Will something like this do or are there different connectors and refrigerant that I need to be aware of?

https://shop.advanceautoparts.com/p...CHAjk1XCPEkBsXvz4zhoCmhgQAvD_BwE&gclsrc=aw.ds


Thanks for the quick reply!

John

 

[Bmarler]

I’d stay away from the auto store kits. The leak sealer stuff is a bad idea, and the kit doesn’t really have a good way to purge the air from the hose before you charge the system.
Use a decent set of gauges, and pure refrigerant and you have the best chance of a good repair. You might be able to find a rental or loaner gauge set too, if you don’t want to buy one.

 

[Hippocampus]

Make sure you use the correct refrigerant for your system and one that’s still legal. Also make sure the system is bone dry. Maybe worth purging with nitrogen first.

 

[Bmarler]

i should have mentioned refrigerant type, thanks for bringing that up. a 25 year old system can certainly have r-22 in it, which has been phased out. there are a number of different types that can replace it, but i'd check with a real tech to see what you might be able to use in your system.
i thought i remembered someone saying small amounts of r-22 might be available but i don't know for sure. hard to say if the widely available 134 will work in your system.
definitely need to verify what you have before proceeding.

 

[Jc180]

Faced with the same dilemma. While aware of the negative comments on a stop leak additive, the alternative is to scrap existing unit and replace with new. Not much to lose. Anyone with actual experience?

And R22 still available for maintenance of existing units, but expensive.

 

[Action]

R 22 is available. However you may need an EPA Certification card to make a purchse from a non-personal source.

There are about a dozen substitutes.
And you would want to fully evacuate the system and not mix gasses.

Action

 

[Barking Sands]

I agree, but it seems to have taken a few years so hoping that it's a product of time. The units are 25 years old. Am I mistaken or do they now sell convenient kits to charge systems?

Will something like this do or are there different connectors and refrigerant that I need to be aware of?

https://shop.advanceautoparts.com/p...CHAjk1XCPEkBsXvz4zhoCmhgQAvD_BwE&gclsrc=aw.ds


Thanks for the quick reply!

John

It may have leaked out over a long period. Depends on the details. It may have just lost performance due to other factors and then recently sprang a leak. It may actually be a very slow leak over time. It may be something else

First step is to see if you can locate 1 or 2 charge ports. If you can find them and you can hook up a set of gauges or even if a single port, hook up a single gauge and see what the current, at rest pressure is. If it has some pressure it may be worth trying. If its zero or close then you likely have a serious leak that will need to be fixed. That will take a bit more skill. If you have the QD type fittings its likely R134. If its the small screw on it could be R12.

If it has some pressure, like say 25 psi, and you want to attempt to service it then buy a cheap gauge set and see if you can borrow a vacuum pump. I am going to assume there is no meaningful amount of Freon left otherwise you'll need a recovery system. Anyways, pull a vacuum for about 15 or 20 minutes and close the valve(s) on the gauge set. let that sit with a vacuum for an hour or so and see if it holds. If it does, disconnect the vacuum pump from the yellow hose and hook up the freon tank. Open the low pressure valve and Service the system by weight if you can locate a placard that has how many ounces of freon to fill it. You'll need a scale. If you dont know the amount by weight you can still service it. Especially if you have a sight glass in the system. Service it with just a little bit. Enough to let the system run without tripping the low pressure switch. Then slowly service with R12 until the bubbles JUST disappear out of the sight glass. I have a few cans of R12 I think. Ill have to check the garage.

If there are no service ports youll likely need to call someone who can braise ports in and do some troubleshooting.

 

[TBill36]

Not sure how to check, but could be the valve. I think they are a schrader valve or very close to it. I had an older unit that had a slow leak in the valve. The tech found it and was able to change the valve without removing the refrigerant. Screwed on a tool that removed the valve and replaced it with a new one without losing refrigerant. He added a little refrigerant and all was good for several more years until I sold the boat.

 

[RRPrather]

Given the age of your unit it is more than likely R22 and is still available although not cheap. I would also recommend to have a professional check it out as there could be many reasons its not cooling well. I do commercial/industrial HVAC and occasionally work on marine units for friends and marina neighbors.

 

[fgarriso]

You need to call someone that is factory trained on servicing marine AC units. Putting the wrong gas in it may do more harm than good.

 

[Iggy]

Putting in a new unit, you can do your self. Personally, I would out weigh the cost of hiring someone vs a new unit. Without numbers, its hard to say but worth looking into before fixing a 25yr old unit.

I new unit maybe worth it using less power?

 

[Sax]

O’Reilly Autoparts has loaner vacuum pumps. They also have loaner gauge sets, but you would probably have to change the fittings to attach to your unit.

 

[STB]

It is very common for the leak to be the service valves. THe spring in the schrader valve goes bad over time, among other bits.

You can unscrew and replace the valve core. But, Amazon sells caps with o-ring gaskets that can seal it and may be an easier approach.

 

[OldDan1943]

Get a tech out to diagnose the problem. Let him recharge the unit after locating the leak or replace the unit.
It is not rocket science but it is refrigerant science.
Some things are not ‘better with age’.

 

[Comodave]

I would check out new units and see what the cost would be for a new unit of the size you need. Then weigh the different factors. Cost of the new unit, new unit will likely use less power and be much quieter. What is the potential cost of fixing the old unit at about $100 per hour plus parts. I am not an A/C expert but installing a replacement unit is pretty easy since everything is there, power, water and ducting. Then make a choice and go from there.

 

[Barking Sands]

I would check out new units and see what the cost would be for a new unit of the size you need. Then weigh the different factors. Cost of the new unit, new unit will likely use less power and be much quieter. What is the potential cost of fixing the old unit at about $100 per hour plus parts. I am not an A/C expert but installing a replacement unit is pretty easy since everything is there, power, water and ducting. Then make a choice and go from there.

I agree with this. Unless its something simple its probably better to replace. When my old unit stopped working I troubleshot it to the compressor. That alone was going to be $600 or more. I just installed a new Marinaire 16kbtu unit. Thats a pretty easy job. Its been great for a few years.

 

[rwaldrop13]

Does anyone have experience with recharging a Marine Air air conditioner? Is this owner manageable? I try to do as much work as possible on my boat.
Appreciate any advice/information.

Thanks,
John

I had 2 units from them brand new and the second unit was defective out of the box and then developed additional issues they refused to warranty. I would suggest since low freon usually indicates a leak scrapping the unit and getting a different brand. I used to be a service manager for a truck/trailer refrigeration service company and have 8 years experience with this type of issue. If you decide to try to repair the leak, use nitrogen to pressurize the system. Get a leak bubble solution at a local AC supply house, don't use dish soap. Don't use leak dye as it will make react with compressor oil and turn acidic, destroying system from inside. PM me for more info.

 

[BroadCove]

I have experience with this - not repairing myself, but a very similar situation.

Current boat has 3 marine air units. When I purchased it, two of them had been recently replaced, and the third (original unit) wasn't functioning properly on survey. The estimate to replace the unit was $7,313 - the a/c, plus a new air handler required due to the change to a newer refrigerant, misc. supplies and labor.

The tech could tell that the existing a/c unit had leaked, but it pressure tested fine (not sure that I'm using the correct technical term). He checked everything and filled w/ refrigerant to spec.

Two years later it's still working fine. It is louder than the other two units, but I don't hear it as the engine room is well insulated. I only know it's louder from my time in the engine room. Total cost was $418 for time and materials.

 

[OldDan1943]

My recommendation is, unless you know what you are doing, get a tech and look over his shoulder.
Recharging it without knowing where the leak is and correcting it may not be the best investment.

 

[STB]

I'll write it again...a very common source of slow leaks on older AC/heat pump systems is aging Schrader valves. This is as true on a boat as it is ashore.

The core of these valves unscrew and can be replaced. There are also caps with o-rings to seal over them. Both core kits and caps with seals are available on Amazon and many other places.

If the compressor sounds bad. If the coils look bad. If things are dented scraped corroded, etc. That's one situation. Damage can cause leaks. A failing compressor is failing.

But, especially if the unit is older and seems to run well, except that it started to cool less and less over weeks to years....I'd try adding a dye, charging it, and capping it. If you want, replace the valve cores first: They just unscrew.

More often than not that'll solve the problem. Not always. But often. I bet more than half the time.

How long will you get after that? Until something in the old unit fails. Aging is funny. Some AC units last ~5years. Some ~30years. And many are replaced due to corroded, leaky drip pans, general corrosion and aging, inefficiency, and older controls -- not hard failure.

 

[jlombardo]

I did stop by the boat this past weekend and take some pictures of the unit. I only see two possible connections; one is labeled discharge and one suction. I expected High Pressure and Low Pressure. Any ideas?


Thanks,
John

 

[Action]

I only see two possible connections; one is labeled discharge and one suction. I expected High Pressure and Low Pressure. Any ideas?

You are correct

The blue is the low side or suction (into the compressor) side.
The red is the high side or the discharge (from the compressor) side.

Filling always takes place on the low side.
The valve taps shown above are sealed.
Likely there are schrader valves under the end covers.
And those covers appear to be rather effective seals.

With the system running, pressures on the low side will determine if there is or is not sufficient refrigerant in the system. The pressure on the high side will determine the health/condition of the compressor and the system.

Pressures will vary based on ambient temperature.

In an automotive system the desired low side pressure would be in the 35 to 50 psi range. (Depending on state of charge and ambient temp) The low side pressure is roughly equal to the temp in Fahrenheit to the air coming out of the evaporator. If the pressure is 40 psi, the temperature discharged out of the evaporator will be about 40 degrees f. Air coming out of the evaporator (system) will pick up heat as it goes out to living space via ducting.

 

[jlombardo]

That is great information. Thank you!
I did call an HVAC guy and he said that he would help me if I knew what kind of gas was in the system. I looked at all that labels but nothing jumping out as to the type.
John

 

[jlombardo]

I did find it, it's R-22. Getting closer.

Thanks everyone for the information!

John

 

[ssteakley]

DIY YouTube videos

There are several DIY How to videos on YouTube, watch several versions, many include links for the tools and parts you may need. Having a tech do it allows you to learn. You may be in a situation some day where you are the only tech available so ask lots of questions and tool up.

 

[ronobrien]

I should add, you should ask yourself the question of where did the refrigerant go? That usually means there’s a leak.

This is why the first step is to vacuum the system to 28" HG and see if it holds vacuum for aprox. 1 hour. If it does the system is probably intact enough to recharge as what ever leak there is would be very small. When it is vacuumed it will probably appear to loose some vacuum as the refrigerant oil out gasses some of the refrigerant. It is owner doable with the right equipment and some knowledge which usually comes with experience. The gauges aren't terribly expensive but the vacuum pump would be several hundred $$. Edit; if it appears to hold vacuum it's a good idea to restart the vacuum pump and run it for several hours to evaporate any moisture might have found it's way. The refrigerant can can be highly hdro-scopic.

 

[Action]

Edit; if it appears to hold vacuum it's a good idea to restart the vacuum pump and run it for several hours to evaporate any moisture might have found it's way. The refrigerant can can be highly hydro-scopic.

To add to this, in a vacuum, water (moisture) will boil. The vacuum pump will suck out the refrigerant and some of the oil. It will boil the water and that vapor will be pulled out too.

I do a lot of my own work on classic cars. Because I live in the valley of the sun all of my classic cars have AC. Generally, if I am going to pull down an AC system with a vacuum pump, I will hook the vacuum pump up and let it run all night. I have my own vacuum pump. And I know there is a rental place not too far away from me that will rent one. Which may be a solution.

I have never worked on a R22 system. I would want to be familiar with operating pressures before doing work.