AC Issues

[PNK]

The product number on the tag is for a Tecumseh R22 compressor used in a/c applications, but it won't tell you who made the a/c system. The AK111AT number indicates it is a 12000 BTU model, 115V.
Very commonly available, so replacement shouldn't be difficult or too expensive, but I am not sure that you can still get R22 refrigerant.
PNK

 

[tiltrider1]

You can still get R22, But!

It is very expensive. How expensive is it? Well, I am in the process of converting my 1982 Ferrari to R134 as doing the conversion is cheaper than buying R22.

 

[Comodave]

If it is indeed a 12K BTU then I would replace it with a 16K unit. Besides being newer and quieter it will match the size better.

 

[Turtle Blues]

16k btu is available as a 120vac unit, easy to install same footprint.
there is a compact 18k but I believe it is 230vac.
Unsuccessfully tried to access Dometic website to lookup - it keeps jumping to RV.
At the risk of thread drift: Tiltrider, was it R22 in an automotive application or R12?
Johnson's Freeze 12 is a direct replacement for r12 rather than replacing all the parts necessary for the conversion.

 

[PhilPB]

The product number on the tag is for a Tecumseh R22 compressor used in a/c applications, but it won't tell you who made the a/c system. The AK111AT number indicates it is a 12000 BTU model, 115V.
Very commonly available, so replacement shouldn't be difficult or too expensive, but I am not sure that you can still get R22 refrigerant.
PNK

If that tag does indicate 12000 btu, my upgrading to 16000 btu would definitely give the cooling we want. As I said in an earlier post I calculated the cubic ft total to under 1000 cu ft. I'm taking this as good news. I also measured the area for an install of 16000 btu Marineaire. It can be done with just a bit of modification to the engine room/galley wall to put it where the current evaporator unit is or I can modify the desk in the salon. I have enough leftover teak lumber and plywood for the desk modification. Either place should be easily doable

 

[tiltrider1]

16k btu is available as a 120vac unit, easy to install same footprint.
there is a compact 18k but I believe it is 230vac.
Unsuccessfully tried to access Dometic website to lookup - it keeps jumping to RV.
At the risk of thread drift: Tiltrider, was it R22 in an automotive application or R12?
Johnson's Freeze 12 is a direct replacement for r12 rather than replacing all the parts necessary for the conversion.

Now that you mentioned it. It was R12. I’ve been working with 134 and 1234yf for so long I forgot the correct description on the old stuff.

 

[Comodave]

If that tag does indicate 12000 btu, my upgrading to 16000 btu would definitely give the cooling we want. As I said in an earlier post I calculated the cubic ft total to under 1000 cu ft. I'm taking this as good news. I also measured the area for an install of 16000 btu Marineaire. It can be done with just a bit of modification to the engine room/galley wall to put it where the current evaporator unit is or I can modify the desk in the salon. I have enough leftover teak lumber and plywood for the desk modification. Either place should be easily doable

You will love a 16K unit. Well worth the effort and cost.

 

[PNK]

A/C Issues

Those comments about replacing with a new and possibly larger unit are the way to go, in my opinion.
Besides the expense of replacing R22, if that compressor was made to operate on R22 it was manufactured in 2010 or earlier, so spending money on repairing it might not be the best option, since you may well be having to replace it soon, anyway.
Hopefully you will enjoy the extra cooling this season; in the Gulf of Maine this past couple of weeks it has felt like we will never need a/c again!

 

[Osprey69]

On my 2019 Dometic the capacitor is a black round cylinder. If you have the same there is a little translucent circle in the top. White when fine, beige when not. Replaced that and starting relay and the immediate problem was solved (threw breaker upon compressor start-up) and an intermittent reboot needed.

 

[PhilPB]

I decided to first go the cheap route and cleaned out the lines with barnacle buster. Increased the water flow some and is cooling better. It's still an old unit and candidate for replacement

 

[Action]

Some times maintenance and cleaning is the best way to go.

Any dust or debris on the evaporator coils will cause the same restriction in heat transfer. There isn't as much dust on a boat as in a home. However the return air should be as clean as possible when it passes through the evaporator. If you can get to the evaporator and have compressed air available, blowing out the coils a little may help too.

 

[PhilPB]

Some times maintenance and cleaning is the best way to go.

Any dust or debris on the evaporator coils will cause the same restriction in heat transfer. There isn't as much dust on a boat as in a home. However the return air should be as clean as possible when it passes through the evaporator. If you can get to the evaporator and have compressed air available, blowing out the coils a little may help too.

I didn't think about that, Thanks! It is accessible and I do have a compressor. That will be my next task!

 

[Action]

The more you can help your system to work more efficiently, the cooler you may be.
And dust or dirt in that cabinet would be stuff to remove.

A bonus would be to post pictures. It may be clean as a whistle. Or maybe not. Would be interesting to see.

And if you are into details, posting ambient air temps and system outlet temps before and after may be interesting to see too. Just kinda going overboard here.

 

[PhilPB]

The more you can help your system to work more efficiently, the cooler you may be.
And dust or dirt in that cabinet would be stuff to remove.

A bonus would be to post pictures. It may be clean as a whistle. Or maybe not. Would be interesting to see.

And if you are into details, posting ambient air temps and system outlet temps before and after may be interesting to see too. Just kinda going overboard here.

I did check and it is very clean. It may have helped that there has always been a filter in place.

As for ambient Temps, I was getting 75°f at the output register and 94-102°f around the cabin. Granted the 102°f was around the drapes on the side windows.

 

[Action]

The general accepted temp spread is 20 degrees (f) between air going into the system and output air. Hitting that metric would be the minimum for understanding if the system is healthy. Sounds like your yacht is pretty close to that.

The system may or may not be sized correctly, however it sounds like it is working correctly.

There are other things that can be done to keep the heat out to start with. Yachts are not necessarily known for being well insulated. Making sure the conditioned space is sealed as best as possible from outside air. Anything else that you can do to block the sun helps as well.

 

[PhilPB]

Would there be any negatives if I added a duct booster fan inline just after the fan coming off the unit? I think I have enough room it would just require a bit of duct changes. I figure that I can remove the duct distribution box and replace it with a tee, with the booster fan attaching to the output of the ac fan and input of the tee.

 

[Action]

Won't damage anything.
If the CFM of the inline fan does not match the CFM output of the AC unit there can be negatives. Both reduce cooling.
Too low and the new fan becomes an air restriction
Too high and the new fan will be pulling air that is cooled less.

The evaporator removes heat. Which is the principal of all AC systems, they do not cool the air, they remove the heat (moisture/dust too) and the air is cool. If the air is pulled through the evaporator too fast less heat absorption occurs.

You can confirm that with a hand held thermometer and your car.
Start car and turn on AC. Measure the output temperature at different fan speeds.
Generally the lower speed is colder.
Now the cold air does not move around as fast or as far. Most will not feel the difference and there is one.

It depends on some other factors as well.

And know the longer or farther the "cooled" air gets away from the evaporator, the more heat and moisture that conditioned air will pick up or absorb. Until the cycle repeats.

 

[PhilPB]

Part of the problem is that I don't know the cfm of the current installed fan. Tried searching but came up empty. Compressed photos are useless. The model looks like 4C140 Dayton

 

[PhilPB]

Also, still not clear about how many btu's this unit is.

 

[Action]

Both pieces of data would be good to know.

The blower motor is AC current, correct?

 

[Action]

This may help to calculate CFM

https://www.omnicalculator.com/physics/fan

 

[PhilPB]

Both pieces of data would be good to know.

The blower motor is AC current, correct?

Correct. AC current.
Also I did find a similarly coded compressor that is a 12k btu.
It is "Tecumseh AK111AR-004-J7 - 12000 BTU R22 Compressor (AK111AT-004-J7)"
Mine is "AK111AT-004" not sure if J7 is significant.

If it is the same and I do have a 12k btu system, that could be the problem

 

[Action]

Or the AT versus the AR

 

[PhilPB]

Or the AT versus the AR

Another good point!

 

[PhilPB]

So we decided to go for a local cruise and then spend the night at our slip to see if the ac could handle the heat in the evening to our comfort. Brought an additional oscillating 16" fan to hopefully compliment the small Vornado fan that I have on the floor of the salon in front of the ac output. The day temp reached 94°f and the night/early morning went down to 81°f. When we made it back into the slip it was about 4pm and we turned on the ac. Took showers and went out to dinner to see if the boat cooled down enough. It took about 5 hours to become tolerable while we watched the TV. When it came time to sleep we closed the v-berth door, which does help cool it down as we have a dedicated ac vent in there. It became marginally cool in there with our dc fans blowing but certainly not as cold as we remembered our use during vacationing last October and November. Still looking at either replacement of the unit, adding an additional unit, or just wait until cooler weather for us to go for our cruises to other areas for a week or so wherever we go. Obviously waiting is the much less expensive option. We use the boat weekly for local cruising but don't stay on board at night.

 

[Turtle Blues]

It's easy to suggest how to spend other peoples money
I did see that the Dometic Voyager is available 18k btu 120vac but think that it is still marginal given your location.
Personal choice would be a 16k in the salon and 12k in the stateroom. Guarantee sleeping at 68' dockside no matter what. But, yeah that's a few boat bucks.

 

[Osprey69]

So we decided to go for a local cruise and then spend the night at our slip to see if the ac could handle the heat in the evening to our comfort. Brought an additional oscillating 16" fan to hopefully compliment the small Vornado fan that I have on the floor of the salon in front of the ac output. The day temp reached 94°f and the night/early morning went down to 81°f. When we made it back into the slip it was about 4pm and we turned on the ac. Took showers and went out to dinner to see if the boat cooled down enough. It took about 5 hours to become tolerable while we watched the TV. When it came time to sleep we closed the v-berth door, which does help cool it down as we have a dedicated ac vent in there. It became marginally cool in there with our dc fans blowing but certainly not as cold as we remembered our use during vacationing last October and November. Still looking at either replacement of the unit, adding an additional unit, or just wait until cooler weather for us to go for our cruises to other areas for a week or so wherever we go. Obviously waiting is the much less expensive option. We use the boat weekly for local cruising but don't stay on board at night.

I am no expert, but would closing the forward cabin door restrict air flow return to the intake (which I presume is midships) to cool?

 

[PhilPB]

I am no expert, but would closing the forward cabin door restrict air flow return to the intake (which I presume is midships) to cool?

Not really, and that was my initial thought too. It's a folding door with 1/2" gap on bottom. Keeping it closed does make it much cooler. The way the ductwork is layed out is the blower connects to a distribution box whuch has two 6" ducts exiting. One to the salon and one to the v-berth. The berth/stateroom gets cooler than the salon and faster due to the decreased size. I guess there is enough air exchange via the door. No leaks in the berth area either

 

[Osprey69]

Not really, and that was my initial thought too. It's a folding door with 1/2" gap on bottom. Keeping it closed does make it much cooler. The way the ductwork is layed out is the blower connects to a distribution box whuch has two 6" ducts exiting. One to the salon and one to the v-berth. The berth/stateroom gets cooler than the salon and faster due to the decreased size. I guess there is enough air exchange via the door. No leaks in the berth area either

Got it. We had to increase ducting in the salon to get it at the same temp as the rest of the boat. I assume your salon ducting is adequate?

 

[PhilPB]

Got it. We had to increase ducting in the salon to get it at the same temp as the rest of the boat. I assume your salon ducting is adequate?

I suspect that it's not but I don't think the current ac system is either. From looking at the compressor I think it's a 12k btu system, not 100% sure about it though.