Hi Steve

trying to figure out something on my Hatt. the plates on my 7 year old Ocean Breeze Condensing units show 16k BTU but the compressors are all AK111AT-001-J7 listed on the Tec. website at 12k btu…

what's the reason for the difference?

trying to make sure my air handlers match the compressor capacities…

Pascal

Well, the previous owner replaced the 1970 vintage Cruisair CUs with Ocean Breeze about a year before i bought the boat in 2003. they're all marked 16k BTUs but the compressors are all the AK111AT-001-J7 which are listed at 12k BTU on the tecumsee website…

I have teh following AH:

Aft Sal. EBS16, 1 year old
Fwd Sal. EBS16, assumed to be original
Master SR, unknown Cruisair, 2 year old, can't read the label on top of the unit. regular fan, not squirel
Guest and bow SRs, original fan cruisairs, both on the same compressor.

system was descaled 3 days ago, plenty of flow out the thru hull, and yes, coils are running hot, too hot too keep your hand on them. air coming out is cold though, i've noted 50 degrees on the fins/tubes.

Problem is that two of the compressors occasionally shut down after running for a while. no HPf on the display, they just shut down.

also, why would one feel cold to the touch, and the other 3 are hot, as high a 160 degrees?

Pascal~

I just re-read your last post…Your saying someone put in 4 of those 16K /12K Eastern condensing units ?…Frankly…Wow…What a mess…

And that explains a-lot…You have too much compressor/condenser btu for the lower deck air handlers & not enough btu for the upper deck.

You will never get those systems to balance out….Or cool/heat like they should….The PO really got the shaft here….Now you too…

These air handlers have capillary tube metering devises that are cut to length & have inside diameter specifically sized for the amount of flow rate of the original compressors…This match cannot be fudged much…You can usually get away with a bit more air handler btu than compressor (not more than 17,000 on a 16K) but never less air handler than compressor btu…

I would say to bite the bullet & change all the air handlers because they are older…But in your upper level you would be loosing btu from the original design by going down to 12's…

Not as much problem below because you need more cooling down there anyway, but one of those 16/12's is still likely not enough for the galley/v-berth/mid stateroom…

Unless it is Cruisair to Marine Air,vise verse, or Aqua Air…I never would use non matching brands for just this reason….They don't match up well at all…Even when staying within an off brand sometimes dosen't work either…

When I was with the Cruisair distributor here…I got called to a Transient boat at the fuel dock of one of the local marinas years ago…It had all King Air (which is built here locally)

One of the split systems had a bad compressor (locked up) so I looked at the label on the compressor to see if it matched any Cruisair model compressor (we stocked them all) it did not…So rather than have a problem such as you have…I called King Air to see if they had one in stock…

I gave them the compressor model number, They said sure…Come on out…So after going to the shop for a check, then to King…I was headed back to the boat with a compressor in a box…I get the thing out to the boat, open the box, and it doesn't match either….What to do ?

I again called King and said…Hey I think I got the wrong compressor have you got the right one ?…They said which one did you get ?

I gave them both model numbers old & new…They told me you got the right one…I went HUH ???

Yeah…We use the same compressor in our 12, 16 & 19K units…I scratched my head on that one but didn't argue…What's the use right ?

I still have a boat to get cool with cranky owners because they are hot…So I cut out the old one & sweat in the new…Evacuated it, then started charging the system, and of course the pressures were way off…It was cooling a little, but not like it should, and I'm sure it's what made the other go bad…

I couldn't even charge the people because it wasn't right…Had to eat the compressor & the day jerking around with it…Can't charge for what you don't fix, and for that matter…Can't Stand Behind…

I learned my lesson the hard way…Luckily the owners understood but of course were not happy…and They had a schedule to keep so there was not time to install a new system…The guy in the next port got that job… 

A compressor too large for a given cap tube will have High head pressure & low suction…Low suction is colder but causes icing of the evap…

A compressor too small for a given cap tube will have Low head pressure & high suction…High suction equals a warmer evap and not much cooling.

Steve~

Post edited 3:20 pm – July 2, 2010 by Steve Pooler

That's all pretty good info Pascal, but along with those readings (specifically comp temps) pressures would be more helpful…

Also…You are taking water coil temp where the freon enters, and before any heat is removed (Freon runs thru the coil the opposite direction of the water)….Pressure readings (both low & high side) will give me overall average temps of each coil…

As I explained above…I'm not very optimistic that you will ever get it right with your evap/compressor combos….

Steve~

I know you asked about this over at the Hatteras Owners Forum…And since we are getting to the bottom of your A/C issues here…here's what I would ultimately do in your situation…

Git rid of two of the condensing units that feed your salon air handlers…Replace them with a single 230 volt 30K unit on one shelf and tee the refrigerant lines together in the engine room…This should lower your amperage draw quite a bit as the larger than 16K units are now scroll compressors and are much more efficient per btu…You would only need one control for both air handlers but they would need 230 volt motors.

Mid stateroom/ V-berth….Remove everything but the tubing & control…Go back with a single 16K with new 5k squirrel cage blower unit located under the outboard bunk, or at the bottom of the hanging locker with duct run up to a box for discharge out the existing hole….Also install a 12K air handler under the fwd seat of the dinette with flex duct thru the fwd bulkhead into that locker and up to the existing v-berth discharge and also make that a plenum box with a cutout for a discharge grill into the galley….This will increase cooling to the galley and the newer squirrel cage in the Mid Strm will perform much better than the original 5K did with less noise….

Master…You may be able to get the existing condensing unit to mate up with a new Cruisair squirrel cage 12K air handler on a new shelf in the hanging locker & ducted to a box at the existing discharge…but no guarantees on that matchup…

I would do all this with 230 volt equipment since I believe you have 230 volt available…It will really help with a balanced load on your genny & shore cord…

Steve~