Richard Kollmann, question for you

[Mozella]

Twenty-five years ago, I built a 55-foot motor yacht. With guidance from Richard Kollmann’s excellent book on yacht refrigeration, I fitted it a combination freezer/refrigerator in the galley and a separate freezer up forward, both very large and both with 12 inches of insulation. They served me well for 5 years of cruising during which time we traveled 28,000 miles, made our own ice, and usually had ice cream onboard.
I sold the boat 20 years ago and the new owner let it fall into disrepair. The third owner is restoring the boat systems with some advice from me.
By the way, I sure wish I could have a copy of your book again. Any chance of a PDF download sometime in the future. I’d be happy to pay for a downloadable version of your book even without any updates or revisions.
The original units were two identical 1.5hp, 115 volt, R404A low temperature, air cooled condenser units fitted with a receiver/filter/dryer and cooling a large holding plate via an expansion valve. We usually ran them only 30 minutes in the morning and 30 minutes in the evening, but they drew enough current so that careful power management was necessary. In truth, they turned out to be more powerful than necessary.
The new owner has elected to install two new condenser units rather than troubleshoot and repair the old ones, neither of which is functional at the moment. The replacements will be identical with the exception of being smaller, (probably ¾ hp or perhaps ½ hp) and being water cooled. The performance of the original air-cooled condensers was compromised because of high ambient air temperatures, particularly the one mounted in the engine compartment. All the other components except for the new condenser units will be retained.


Commercially available condenser units intended for shore-based use all include a water control valve which has a sense line connected to the compressor high side. Apparently, these valves are used to limit unnecessary water use and also control head pressure.


QUESTION: Should the current owner retain the water control valve that is integrated with the typical water-cooled condenser unit, or should he remove it? It certainly isn’t necessary to limit water use.
If Richard doesn’t reply, perhaps someone else can chime in with an opinion.

[Bowdrie]

Originally Posted by Mozella

If Richard doesn’t reply, perhaps someone else can chime in with an opinion.

I'm sure he'll show up at some point, or you can send him a PM.
In the meantime; many, if not most of the small>medium sized water-cooled condensing units used on yachts don't have water flow controls, but they can be of good use, particularly if the boat travels from very warm water to places like Alaska.
Going from 85F water in the Sea of Cortez to 35F water in Alaska makes a big difference in required water flow.
That said, many "land based" units might not give the best service if their condensers and water flow controls are not designed for saltwater service.
That would be my 1st concern in evaluating a commercial unit that was going into a boat, "Will the condenser and flow system hold up to salt water?".

[Mozella]

Thanks for the reply. This vessel is unlikely to leave the Gulf of Mexico, so wild swings in water temperature are unlikely. Of course the water cooled heat exchanger which makes up the condenser must be cupronickle for use in salt water and the pump and other hardware must be marine rated.