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Jul 13 2011

Installing the Norcold Refrigeration Conversion Kit

When we were deciding what upgrades we need on our boat, we always kept in mind what our ultimate purpose was – long distance voyaging.  Not to confuse “cruising” with “voyaging”, you should understand the differences.

Someone that cruises, be it short duration or long, is considered to be partaking in more of a coastal marina-hopping type of lifestyle.  Perhaps visiting close by islands on occasion, but mostly staying close to the coast and tying up in a protected marina as opposed to at anchor.  On the other hand, someone that voyages has the expectation of being out at sea for extended periods between stops.  They may choose to mostly anchor in coves and stay away from the marina scene.  They will probably make frequent use of a skiff or tender to take them to shore where they will mingle with the local inhabitants and buy food supplies from the local market to restock.  They may have to look for temporary work, or barter, to make ends meet.  They are the type that will need to collect rain water, grow some of their food aboard, use solar and wind power for generating electricity, and generally live off of, and at harmony with, the sea.  They also catch fish whenever possible, and if there is a lot to catch, they will need to dry, can, or freeze the leftovers because you will need them for those days when you don’t catch any fish.

We are most certainly looking forward to voyaging and all the adventures that it offers.  The cruising scene leaves me dry.  I think I would be so bored that I would think I should have just stayed at home.  If I wanted to be within that comfort zone, the wife and I could just keep our office and keep working.  That in mind, we decided that refrigeration would be a good idea.

After making that decision we then needed to decide what design we wanted to install.  We could have opted for an engine-driven system, but diesel is not a renewable resource, so that was out.  The cold plate solution looked like a good and efficient way of refrigeration, but with all the other preparations we were going to need to make, it was a more expensive option.  After considering expense, power budget, and what we would use it for, we decided on the Norcold conversion kit.  I promptly made a trip to West Marine to place an order.

A week later I received a call from West Marine telling me that the unit had arrived.  Although I was really excited, I could not get down to the store until the weekend, so by the time that Friday evening arrived we were off to pick it up.  It didn’t arrive a moment too soon, as our trip to Catalina Island was coming soon.

Because we had so much to do before heading out to Catalina, I decided to work on it that evening.  The wife decided that she would be in the way, so she graciously agreed to take on the daunting task of imbibing with the locals at the Friday night marina party.  She is so good to me!

In the planning I had installed the conversion kit many times in my mind, and had planned as much as I could without having the actual kit.  I won’t say that it went off without a hitch, but it was an easy install.

The first thing after unboxing what was shipped and doing a quick inventory, was to decide where to mount the cold plate.  The instructions had several suggestions on what orientation to use for the plate, so it wasn’t difficult to decide what was best for our box. 

The routing of the copper tubing from the plate to the compressor was easy because there were already holes where the previous system had been installed, and I could use those for the new system.  I placed the plate into the box and marked where the mounting holes would have to be drilled to screw in the standoffs for the plate.  I routed the copper tubes through their holes and by turning the plate, was able to carefully pull the tubes through the holes without bending them too much.  On the other side of the box I was recoiling the tubes so that I could tie wrap them and clip them to the outer wall where I was going to mount the compressor.  I used four standoffs to mount the plate, as that seemed to hold the plate well and I didn’t have to drill any more holes in the box.  I then screwed down the thermostat to one corner of the box and routed the wires for the thermostat and the sensor through a smaller hole and connected them.

The compressor was going to be mounted below the sink in the galley on the other side of the box.  It had to be in a place where there was ample ventilation so that the compressor could cool itself.  Below the galley sink is also open to the bilge, which is cooler than the rest of the boat.  There is also a large area above where the heat could flow upwards.

For mounting the compressor, I would need a small platform for it to bolt to.  I fabricated a IMAG0001platform out of wood, and screwed it to one of the walls below the sink.  I attached a short leg to the front side, and used a long steel “L” bracket to screw the platform to the other side.  This ended up being very sturdy.  Although the compressor kit came with two methods of bolting it down – large wood screws or bolts/nuts – they left the nuts out of the kit.  I had decided to use the large wood screws anyway, as they looked as if they could hold it without any problem.  There were nice rubber shock mounts included, which really work to dampen the vibration from the compressor.  There is little noise/vibration anyway, but this was an added bonus.  There were a few odd angles that I had to hold the drill to drill the pilot holes, but it worked out.  There are no templates with the instructions that could be used for drilling hole patterns.  I guess I could have made one, but it was easy enough to drill through the mounting holes and screw it down.

After mounting the compressor and deciding where the wiring should be run, it was time to connect the copper tubes to the compressor.  The system comes pre-charged, so care needs to be taken when screwing down the connections.  The instructions aren’t as clear as they should have been, but the system is simple, so it is still not difficult.  There is no way to confuse which line connects where, as they are male and female on each end.  The instructions state that once you screw the connections together, do it quickly to minimize freon loss.  A bit scary because there is no (simple) way to recharge this system.  If you mess up and let out too much freon, you will need to return the unit to be recharged.  I screwed the connections down until they were just starting to be snug, and then quickly tightened them.  I only heard a slight hiss for less than a second on one of the connections, so that was good.

Time for testing.  Instead of connection to 12 volts, I decided to plug in the 120v line to test.  I had an extension cord handy, so I plugged it in and turned on the switch on the thermostat.  At first I thought something was wrong because I only heard a slight hum.  I thought perhaps it was an AC hum and that the compressor had not started.  To my surprise the compressor was running, but was just really quiet.  A good thing on a sailboat where the most noise you want to hear is the wind and water.  I put my hand on the cold plate and noted that it was starting to become cool.  Cool!!!  I gave it a few minutes to run and was happy to feel that the cold plate was getting really cold.  Happy times!

I cleaned up the installation by tying up all the tubes and wires out of the way, and had a beer.  The next day I connected the system to 12 volts and turn it back on to find that all was working well.  Since then it has been running for several days without any problems.  I was initially concerned about the heat generation of the compressor, but it only becomes slightly warm, and this is after almost constantly running to cool the too-large box that I installed it into.  I installed a small fan to suck air through the top of the condenser to help with efficiency.  I also installed a small fan in the box to circulate the cool air around all the food, and that seemed to help.  To finish I foamed in the holes that I ran everything through.

Because our box is 10 square feet and the unit is designed for six, I will be installing a Plexiglas sheet with a door in the middle of the box to separate the upper and lower sections.  This should really improve the operation, and allow the unit to cycle and be more efficient.  More on that later.

For the most part this was a really easy install.  It took me a total of about six hours from start to finish.  Although the instructions leave a bit to be desired and there were mounting nuts missing, nothing really hindered the install.  I would recommend this system to anyone needing refrigeration.  I am not yet able to test whether or not you can freeze anything by having it touching the plate, but the plate has no problem forming ice on it, so I suspect that you can.  The rest of the box stays fairly cold, so milk, cheese, and beer stay cold.  Butter stays as hard as it does in the fridge at home.  As soon as I can find a good thermometer I will do more testing.

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