Compressor vent on a Mark II

[Mick Laver]

Hi all
The Adler Barbour (now Dometic) compressor for our fridge is located in the stbd lazerette and vents into the enclosed space. From my rough eyeballing of the space there's no where near the recommended volume to vent the compressor properly, especially when both aft lockers are full of stuff (as they always seem to be). There's a space right above the compressor where hot air would get trapped, and it seems like that would be a obvious  place for a vent. So obvious to me that I'm wondering what I'm missing.

I've attached a couple of pictures of the proposed location. Anyone done this?

[Noah]

I would (maybe) worry about water getting in there when you wash down the boat?

[scgunner]

Mick,

Are you actually getting a noticeable buildup of hot air? My compressor(Adler Barbour) was installed there at the factory with no additional venting and has always worked fine.

[Mick Laver]

No, I haven't noticed any heat build-up, but to be honest I haven't really been checking. Perhaps when the air temp heats up in a few months and the compressor has to work harder it'll be more noticeable. I'm not looking for "a solution in search of a problem" so I'll put off putting large holes in my boat until I can verify heat build-up IS an issue. I thought someone may have already added a vent and determined that it helped.

Here's the relevant section from the installation manual.

VENTILATION REQUIREMENTS
The ColdMachine is a device that moves heat from one place to another. It does not "create cold." The heat removed from your icebox by way of the evaporator is transferred to the air around the condensing unit. If you locate the condensing unit in a small, hot or confined enclosure, it will suffocate. Its built-in fan will have to re-circulate hotter air. It will run continuously, draw excess amps and not cool efficiently. It will never shut off and its performance will be unacceptable.
Let the unit breathe! Position the condensing unit so that its fan can intake air from one space and discharge it to another. Do not re-circulate the same air unless the compartment in which you mount the unit is 100 cubic feet/2.83 cubic meters or larger in volume, unobstructed, and mostly below the waterline.

[Stu Jackson]

Mick, there have been two or three places most compressor units have been installed in the Catalina 34 over the years:

1.  Lazarette
2.  Under starboard settee, forward of water tank
3.  Under forward section of starboard settee, just forward of the mast

This is for Mark I boats.  Mark II boats have their water heaters in a different spot than the Mark I boats, thus reducing the options, eliminating #2.

[Others have reported installations under the stove (!) and in the nav station hanging locker.  Rare, but reported.]

In the past 22 years I have never heard reports of insufficient cooling in the lazarette location, it is a huge space.

What we have heard, repeatedly, is that the other two locations REQUIRE additional ventilation.  This was true as early as the late 80s in tech notes for those skippers who had their dealers install the units down below instead of aft.

The compressor doesn't get hot, it's the condenser (the "radiator" with the fan on it), which is designed to remove the heat, and which can't work properly in a confined space.

The lazarette location is actually the best one on our boats.  It doesn't need anything else.

My boat is almost 34 years old and we've owned her since 1998.  Other than replacing the electronic module in 2016, it is the original unit and has been working just fine in the lazarette.  I have sailed in the California Delta in over 95F daytime heat for many summers.

The VERY LAST THING you ever want to do is let any water into the lazarette.

[mdidomenico]

just an observation.  i know you don't need a new compressor, but the compressor catalina direct is selling now have an optional water loop to combat this problem.

[Stu Jackson]

Water cooled compressors:  from extensive reading on Cruisers Forum and Kollmann, this idea has been reported to be less useful than many may think.  The additional complexity is reported to not be worth it, even in hot climates which usually have higher water temperatures, too.

I suggest that before anyone goes this route to do a lot of research.

[Ron Hill]

Mick : If you really think it's a problem why not try a battery operated fan to move the air inside that compartment.

I wouldn't go for the vent that you've shown, as washing the boat and storms will surely let water in!!
There might be a sophisticated vent that will collect any water that might come in, and then drain it out?

A thought

[Roc]

I've never seen a problem with the location of the unit.  During the season, I leave the fridge on 24/7. 

[scgunner]

I'll second Roc, except I leave my fridge on 24/7/365. My feeling is that the guys who built these things(C34s)may have known what they were doing.