Tuesday, February 5, 2019

2017 & 2018: 5 Refrigeration in a Kit

New Fridge and Freezer.

We still had the original Grunert freezer and fridge which were operated by a single 110 volt compressor.  This necessitated running the generator while at sea, twice a day for around half to one hour (depending on air  temperature), or using shore power, to bring down the temperature in the cold storage plates.  The boat also had to be in the water as it used sea water for cooling the compressor.  Eventually, it also leaked gas - oh so slowly so that it couldn’t be detected by my elec detector – an unusual expensive type of gas not readily available, especially in Europe, of course.

As the Grunert fridge/freezer couldn’t be used at all on the hard, shortly after we purchased the boat (now some 12 years ago) we purchased and connected an air-cooled Waeco car fridge/freezer in the store room.  It uses 12/24/110/240 volt (you choose) and you can use it as a fridge, freezer, or whatever you like as you set the temperature digitally.  Uses about 3 amps once at set temperature and makes no noise.  We love it and wanted the same for the fridge and freezer, except just 12 volts would do. So, I searched the internet and Penguin Marine in the UK had a very user friendly planner that you follow yourself before contacting them for a quote.  As it turned out they were also very professionally friendly as I did need to call and clarify a number of matters that needed to be sorted.  See below.  Remember the boat was in Portugal so UK is convenient for me in many respects: they speak English (and understand my aussie accent) so it's easy to speak in technical specifics and no customs duty involved.

Firstly, I removed the old compressor – it weighed a ton and just dropped it over the side of  the boat, then wangled it into a dumpster in the yard.  Same with the cold plates – one had to be cut into two to get it out of the fridge (it also served as a shelf) which I did using my high speed grinder.  They also weighed a lot.

The most important aspect was to measure the size of the compartments, in my case the fridge is …. litres and the freezer … litres.  The fridge and freezer run fore and aft along the side of the hull, their tops forming part of the main counter top in the galley.  The company site has the formulas to work out volumes for odd shapes which are fairly easy to follow but I also left it up to them to do the maths and, therefore, recommend the appropriate respective sizes for compressors and evap plates.  This involved a number of emails and finally a phone conversation or two to sort it all.  We ended up with a bigger evaporator than originally identified for the freezer so it’s worth the effort to get it right.  Very important obviously but in the end it worked out quite well.

The kit that was recommended by the company was two Frigoboat compressors (one for fridge, one for freezer), an evaporator plate in each of the fridge and freezer compartments, water cooling for both while in the water (quieter, better for hot climates, less power required) and a separate air cooler for the freezer (my choice) which allows it to be run on the hard (with the Waeco in support as the fridge).  There are also two thermostats – one for each box.  There’s also a ‘control box’ that controls the compressors, and the water pump turning them off and on after feedback from the thermostats which are attached to the evap plates. 

Access into the fridge and freezer for fitting evaporator plates was a challenge.  The fridge has top and side access which is necessary as the GS used to almost fall in when accessing from the top to get at things on the bottom.  The fridge is actually quite large.  The freezer only has a top access hatch and we found it was just too small to fit the evaporator through.  So, I had to remove the petition separating fridge and freezer compartments and glassed over both sides of the foam as the original veneer had largely separated from the foam and rotted.  It made for a much better petition and I put it back after I had put the freezer evaporator plate into the compartment via the fridge.  I then sealed/fixed it in place using silicone sealant, but you could use some other adhesive sealant, as the silicone is a bit smelly for quite some time before the odours eventually go away.

Only after the petition was in place could I then fix the freezer evaporator plate (a U shape)  in place as one side had to be attached to the petition as well as two other sides (front and forward bulkhead).  The outside wall of the freezer (which slopes downward as per the side of the boat) could not be utilized due to the large size of evaporator plate we needed.  The evaporator plate for the freezer came bent to shape with all the other bits and pieces and fitted just right.  This is where the measurements of the compartments (by me) are so important.

The fridge evaporator plate arrived unbent to shape (it should have been L shaped ie to attach on two sides of the fridge compartment) and I had to do it myself, which shouldn’t have happened.  The staff at Penguin were apologetic, however, yet very helpful and explained what to do and how to measure correctly, etc.   Briefly, I heated the plate with my heat gun where I had to bend it until it was too hot to touch then bent it (using gloves) over a piece of pvc pipe I scrounged from around the boatyard.  This particular job, dare I say, turned out to be the easiest and simplest of all the jobs surrounding the whole project, although I was somewhat nervous beforehand I admit.

Now the real fun began. The plates have (pre-gassed) gas copper lines fixed to the plates (soldered?) in a coil, which have to be unwound and then fed through their respective openings eventually leading to the compartment identified for the compressors, while using minimum bending and unbending.  This was a challenge but what I did was unroll them first making them more or less straight before inserting them through the various openings as I fed the evap plates into their respective boxes.    The freezer pipe and plate fed via the fridge with the pipe being fed through a whole in a bulkhead separating the freezer compartment and the saloon, into the compressor area which is under the saloon fore and aft seat.  Once freezer evap plate was inside its compartment (just loosely) I fixed the freezer/fridge petition into place.  

Once the petition was fixed in place I then fixed the freezer evap plate to the petition and two other walls.   This is a bit fiddly as there are a number of spacers which have to be fixed behind the plates to keep them just off the walls.  Another reason that the measuring process must be quite right for the U shaped plate, much less so for a L shaped plate.  In the case of the fridge its piping went through a hole in the outside edge of the petition, then through the freezer compartment, through the bulkhead hole into the compressor compartment.  I was alone to do all the above and it would have been much easier if I had an assistant to help manhandle the copper pipe while also manoeuvring the evap plates.   Much cursing.

I bent the copper pipes out of the way while I mounted the compressors, air cooler, and the control box.  Beforehand I had mounted the water pump after taking out the old 110 volt pump.  I utilized the old mounting for the 12 volt water pump.  The air cooler had to be mounted next to the freezer compressor as you need to change the couplings between compressor (when it’s in the water) and the air cooler copper pipe when it’s out of the water.  You need to minimize any bending or unbending of copper tubes.  The couplings are easy to connect and disconnect – no real tightening to be done other than the minimum as per the instructions.  You also don’t lose refrigerant as you change connections.

Next to last step was plumbing.  I used the same thru-hull sea cock as for the old 110 volt system, then ran intake hoses to each of the compressors, then outlet hoses from compressors to the same old hose for the water to pump out overboard via the sea cock on the side of the hull.

The final step was the wiring and, as I had run out of switches on the switchboard, I fitted a small switchboard with separate switches/circuit breakers, connecting them to the power and then to the control box.  A bunch of other wires from compressors, thermostats, water pump all connected to the control box.



And it ALL WORKED, thank goodness, and very pleased with the result.  The freezer really is a deep freeze and the fridge works a treat.  I put shelving in the fridge too and also floors in both fridge and freezer.  I attached plastic netting with plastic cable ties to the faces of the evap plates to help protect them from bumps etc.

Also, at the very start I serviced the seal for the top loading fridge hatch.  Ever since we purchased the boat, part of the seal had become a bit twisted and so the seal was never perfect.  I found that by using the heat gun I could twist it back to its original shape and it has seated perfectly ever since.  If only I’d known this 12 years ago.  In preparation I had also read up and looked at YouTube videos, which were all very helpful.  Although it was some effort to put together, we're wondering why we persevered with expensive re-gassing and inefficient cooling over the years.  Now, it's all working a treat.


No comments:

Post a Comment