This season, I noticed Soave’s fridge seemed warmer than I would like. I threw a thermometer in and checked it periodically and generally saw temps in the mid 40’s but on warm days I would see 55ºF or so… I began to research options.
I’m not a fan of how our current fridge is integrated into our galley, but Soave has many more pressing maintenance items than marginal refrigeration, so I decided to focus on a quick fix in place approach so we’d have cold beverages while working on other maintenance items.
I couldn’t find any gas leaks so I topped-off the refrigerant ( R134A ) and will continue to monitor for performance and gas leaks. So far performance has been satisfactory. I was able to adjust the thermostat to a middle position and mostly maintain satisfactory temp.
To monitor performance I added temp/humidity loggers in Soave’s fridge, cabin, and engine compartment. The data surprised me, and may motivate me to make some changes. Below is the data I collected. 7/14 was the day I topped the refrigerant and added the real time logging.
First Observation - My compressor ( isotherm ) is in my engine compartment. It’s user manual says performance will start to decline when ambient temps exceed 95ºF. This week my engine compartment was over 100º F. for several hours a day and when it was Soave’s compressor could not maintain the set temp in her fridge. Each night the compressor “caught up” as evidenced by cycles in both fridge temp and engine room temp ( the sensor is near the compressor ) When compressor is on if it’s extracting a meaningful about of heat the temp in the engine compartment rises, if it’s not able to extract heat it does not show on the temp monitor.
Second Observation - Compressor is drawing air randomly from a high location in Soave’s engine compartment. Air from her bilge would be much cooler.
Opportunity/Hypothesis - Some “best effort” ductwork and a small exhaust fan wired to come on when temps exceed 95ºF might improve performance of Soave’s fridge and any other temp sensitive equipment in my engine compartment.
Questions for the group -
Has anyone attempted to moderate engine compartment temps ? If so what did you do and how well did it work ?
Will a more moderate temp have other benefits for other equipment in the engine compartment ?
Any tricks I can use to help the isotherm perform better in high temps ?
Other thoughts ? Like I’m crazy for even collecting temp data.
Personally, I admire people who collect data so in answer to your fourth question: good on you!
I don’t know the N33s, so my few comments should be taken with several grains of salt, but:
A number of the other models came with blowers in the engine compartment that are ducted to clamshell vents on the coaming sides, and those could be brought into play to cool the engine compartment
Unless the N33s were built to a higher standard than the N26’s that I know best, you may want to take a look at the insulation around your fridge and see if there’s any way to beef it up. When I put refrigeration into my previous N26, I both decreased its size by putting additional insulating walls and floor on the inside, AND injected foam into the empty spaces between it and the surrounding cabinetry. The factory-installed insulation was just an inch or two around the box. (I think there’s a section in the New Nonsuch Owners Quick Guide on this topic.)
A couple of years ago, I was having a refrigeration problem and could not find the refrigerant leak until I cut away some of the spray-in insulation. If all else fails, you may want to check that out.
Bob & Joe,
Good points… from what I can see my 3 year old isotherm was installed without any upgrades to the cold box insulation or much consideration it’s operational efficiency.
In Joe’s case, having the compressor in the cabin (behind his stove ) means temps seen by the compressor are moderated by dorado vents. Soave’s cabin is about 10 degrees cooler than her engine compartment during the hottest part of the day. Make me wonder how much space is behind my stove ?
Maybe my best course of action is to live with what I’ve got till it fails and continue to collect ideas about best practices. I have my doubts that it is worth trying to relocate my existing compressor. It uses precharged lines and the connectors probably won’t re-seal reliably and the lines won’t respond well to being rebent to follow a new path.
Next time I’m on Soave, I’ll check if there is an easy way to increase ventilation in her the engine compartment.
When Soave’s PO upgraded refrigeration, autopilot, hotwater, and inverter/charger a fair amount of 3" ductwork was abandoned in place… it’s on my todo list to inspect what’s there and determine how it was intended to work. Maybe I’m closer to an engine compartment venting solution than I realize ?
When my the engine driven refrigeration system stopped working. I went with a 40 quart Engel 12/120 volt refrigerator/freezer. https://amzn.to/3y2OCxl It sits in the cabin on the port side and allows easier to access than the built in icebox in the Nonsuch. It operates 24/7 on 12 volts and has never run down the battery bank which is connected to two 75 watt solar panels. I find it better to use than the built in icebox. I use the icebox as dry storage for things like my bread maker etc… It also serves as a convenient seat to use the cabin table without opening up the table.
Hi Mike,
Yes… This is the direction I was headed before I looked at the nameplate on Soave’s compressor and discovered it was only 3 yrs old. I splurged for a $10 can of refrigerant and since my informal circle of “friends with tools” didn’t already have refrigeration gauges I picked up a $50 set of gauges marked for R134A refrigerant. So far ( fingers crossed ) we still have chilled beverages.
I admire the Nonsuch designs and the creativity of Soave’s POs, but the evolution of marine technology now offers new possibilities. Compressor tech has come a long way baby! I’m using inverter AC units in my home that consume less than half the power of the 8 year old units that I retired last year. It’s only a matter of time till the “electrification wave” of technology gets applied (successfully) to the marine markets.
I’m glad I went the fix-it route ( for now ) with refrigeration because I’m starting to see a sorta “master plan” emerge for adapting Soave for the kinds of cruising that Linda and I end up doing most. I want to preserve my flexibility ( for now ) by minimizing changes and using what I have. This allows me to learn more the pros and cons of the current systems.
If my compressor fails, I would definitely look at portable solutions like yours. The make a lot of sense to me.
I’ll also continue to contemplate the bigger picture of organizing Soave’s engine compartment and utilizing the space behind the ice box and possibly the ice box differently. Requirements need to drive the reorganization, and at the moment power management brings lots of questions. I need to decide if I should continue to use diesel and propane to store energy onboard or if electrification would better serve Soave’s longterm power management needs. Huge decision unfortunately driven by guesses about the about of life left in key onboard systems.
Looking forward to ongoing discussions about maintenance and innovation among Nonsuch owners because Nonsuch’s provide a simple yet robust framework to work within.
Hi Leon,
What method(s) did you use to find the leak ? I’ve heard the sniffing tools are not sensitive enough to find a slow leak.
I suspect my leak is very slow and may have been resolved when I tightened the fittings that I could reach ( although none of them seemed particularly loose ). My current thinking is continue to monitor and that eventually the leak will become detectable and I can repair it.
At the moment it seems to be holding the set temp pretty well as long as the engine compartment ( where the compressor lives ) isn’t more than 105º F.
