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OK so I must of stepped on the refrigerant line while climbing in the sail locker and lost my R12. It is slightly more expensive than platinum, so I decided to replace my refrigeration system. I have read the mail list information that I can find and it seems to border on anchoring with everyone having a different opinion. I like Walter’s solution of adding the insulation to the inside of the box but I wondered if the condensation in the old box had caused a smell or any problems. It should be easy to seal the FRP panels so there should be no actual leaks. It seems like when installing a new unit it would be the right time to insulate.
I am looking at a couple of DC driven units that use the same technology that Pete’s thermostat does, drawing the temp down while there is extra power from shore power or another power source.
Does anyone have recommendations for the size or brand of refrigeration. I also wanted to know if Walter has an update on his insulation job. Have you had any issues? Tor I know that you were adding insulation how did that go and what technique did you use?Thanks for any input
Linus
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I have to replace one copper line. I was told by the yard that all the fittings on the evaporator and the expansion valve would have to be replaced if I changes to R134. Also the unit is 27 years old and water cooled. A pretty good life span I would say. I plan to go back with a water cooled unit.
Linus
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Linus,
Since you are replacing the whole unit anyway – my recommendation is to go with air-cooled, if you can feed enough air to the condenser. I've lived with a water-cooled SeaFrost for the past 6 years, and if the unit ever fails I will replace it with an air-cooled condenser. Last summer, here in the Trent River, I had to clear the raw water strainer almost weekly with all the grass and other crud coming down stream. It was worse than the Chesapeake Sea Nettles. Your story of getting an eel in the strainer basket made me more than a little anxious when opening the strainer.Although Cleave Horton at SeaFrost will still recommend a water-cooled compresser if you want a decent sized freezer, the new Danfoss compressors that he and the other manufacturers offer are very efficient even when air-cooled. Unless you have a compelling reason for the little extra efficiency of water cooled or you don't want to vent the compartment where the condenser will be located, I'd go air cooled.
On Thu, Oct 29, 2009 at 8:04 AM, Linus Martinez < ([email][/email])> wrote:
Quote:I have to replace one copper line. I was told by the yard that all the fittings on the evaporator and the expansion valve would have to be replaced if I changes to R134. Also the unit is 27 years old and water cooled. A pretty good life span I would say. I plan to go back with a water cooled unit.
Linus<.. snip>
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My guess is that you have the same unit that was put in my boat 30 years ago when she was built. If you like an engine driven system and don’t mind learning enough about servicing it to keep it running you might consider fixing it. Your yard is giving you the wrong information. In either case you might want to buy one of the two books on the page below.
http://www.kollmann-marine.com/To switch to R-134, you need only replace the oil in your compressor and recharge the system. You may optionally change the expansion valve but it isn’t necessary. If your compressor is an original piston type compressor you could replace it with a new rotary compressor for about $300. In theory, you could remove the damaged tube and have someone make a new piece. Retrofit or replace your compressor. Run a vacuum on your system and recharge with R-134 and be back in business.
Rich
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Lady Leanne never had refrigeration, just the old ice box. We determined that we really didn’t need freezer capability and installed a 12V Sea Frost air cooled system last Fall. We did not add any additional insulation, but did put a bathtub plug over the drain in the bottom. I keep a thermometer in there to track performance. The fridge now keeps the top starboard shelf at about 45 degrees (great for vegs/ red wine), the port middle shelf at around 40 (dairy/ white wine) and the bottom of the box it is around 35 degrees (perfect for those cold brewskis). My boys have found that they can put their icesicle treats against the plate and they will freeze.
Presently, the unit runs off of an inverter at the dock and house batteries when out sailing. We plan to add a genset later as we upgrade the whole electrical system for longer term cruising.
We turn off the system when we leave the dock for sailing (to avoid battery drain) and find that all will keep adequately cold for up to 5 hours. This is sailing in Hawai’i with average 85 degree days.
We’re pleased with this setup.
Dan Kalinowski
Lady Leanne II (#135)
Honolulu -
Lady Leanne never had refrigeration, just the old ice box. We determined that we really didn’t need freezer capability and installed a 12V Sea Frost air cooled system last Fall. We did not add any additional insulation, but did put a bathtub plug over the drain in the bottom. I keep a thermometer in there to track performance. The fridge now keeps the top starboard shelf at about 45 degrees (great for vegs/ red wine), the port middle shelf at around 40 (dairy/ white wine) and the bottom of the box it is around 35 degrees (perfect for those cold brewskis). My boys have found that they can put their icesicle treats against the plate and they will freeze.
Presently, the unit runs off of an inverter at the dock and house batteries when out sailing. We plan to add a genset later as we upgrade the whole electrical system for longer term cruising.
We turn off the system when we leave the dock for sailing (to avoid battery drain) and find that all will keep adequately cold for up to 5 hours. This is sailing in Hawai’i with average 85 degree days.
We’re pleased with this setup.
Dan Kalinowski
Lady Leanne II (#135)
Honolulu -
Lady Leanne never had refrigeration, just the old ice box. We determined that we really didn’t need freezer capability and installed a 12V Sea Frost air cooled system last Fall. We did not add any additional insulation, but did put a bathtub plug over the drain in the bottom. I keep a thermometer in there to track performance. The fridge now keeps the top starboard shelf at about 45 degrees (great for vegs/ red wine), the port middle shelf at around 40 (dairy/ white wine) and the bottom of the box it is around 35 degrees (perfect for those cold brewskis). My boys have found that they can put their icesicle treats against the plate and they will freeze.
Presently, the unit runs off of an inverter at the dock and house batteries when out sailing. We plan to add a genset later as we upgrade the whole electrical system for longer term cruising.
We turn off the system when we leave the dock for sailing (to avoid battery drain) and find that all will keep adequately cold for up to 5 hours. This is sailing in Hawai’i with average 85 degree days.
We’re pleased with this setup.
Dan Kalinowski
Lady Leanne II (#135)
Honolulu -
Linus,
Unless you really want to change your system for other reasons, my advice would be the same as Rich’s. I converted my system to R-134A about five years ago. In fact, it was not necessary to remove the old oil from the system. Auto parts stores have conversion kits that include a quantity of conversion oil that makes the old oil compatible with the new refrigerant.
Phil FontaineQuote:
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OK maybe I was looking at the deal that I thought I could get on a new system. I was told that the few units that the yard had switched to 134 had only lasted one year and then seized. I thought that at this point I didn’t want to spend any money on a unit that I would have to replace soon. I spent a couple of boat units on repairs on the engine just before I replaced it. I sure could have used that money for the repower.
Linus
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Linus
Before spending any money on your system I recommend getting one of the books listed below. Then you’ll be able to make informed decisions.Your engine driven system is aging. If you can find someone who will service it cheap or learn to service it youself, it can probably provide good service for many more years. They are maintenance items. If you’re paying shop rates to get the thing serviced it can put you in the poor house (or boat). If you don’t have the patience or confidence to learn to service it yourself you might look around to see if you can find someone who service car AC systems. That’s basically what an engine-driven system is.
On the other hand, a complete new 12v system doesn’t come cheap either. Sorry, you’re between a rock and a hard-place.
If you get yourself a set of AC gauges (harbor freight has good prices) and a half-dozen cans of R-134 from Walmart you’ll have enough to get your system up and running again. You have nothing to lose except pearhaps an old compressor that you might damage by overcharging the system. If you have questions about specifics, fire away. We’ll try to coach you through it.
Rich
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Rich
My unit is a 12 volt Grunart that has an charging sensor like Pete makes and has been great. It only runs hard when plugged in or running the engine. There is a huge compressor in the port sail locker which is where the kink in the tubing is. I have quite a few friends that have helped me out with refrigeration issues in the restaurant. I think for a few beers and wings I can try the 134 before biting the big one for the new unit.
Thanks I’ll let you know how it goes.
I do have one more question for the group. The unit has a 120 volt AC sensing wire that was hooked up to the old Raritan converter. Now that I have installed an inverter it is a different hook up. My guess it should go to the charger out somewhere, but that is obviously 12 volt and the panel is labeled 120 volt sense. Does anyone have a similar unit?Linus
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Linus-
We have a 12V, 1/2 hp Grunert on Clairebuoyant. We are happy with it. It runs on R-12, slightly more efficient than R-134a but not so green.
Did you actually break the tubing, meaning the refrigerant leaked out, or simply kink the tubing stopping the flow? A system that has been open to the atmosphere is going to take some work to get right again. In this case I’d take Rich’s advice, convert to R-134a, or other environmentally frendly chemical with better compatibility, install a return line filter receiver very important to avoid contamination and compressor failure.
If the R-12 is still in there, agreed unlikely, maybe you can pump down the unit, trapping the refrigerant in the compressor/ receiver assembly then fix the copper tubing.
These systems were built before anyone had battery banks large enough to support 40 amp dc power drains. They have a relay that enabled them to run only if a charging source was available. The Grunert specifics are probably on the Internet.
If you are like us, you have the compressor shown as an example in Caulder’s book, kind of oval looking from the top, as opposed to square or cylindrical. This is a great industrial unit. I wouldn’t be too quick to replace it.
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Linus,
It sounds like that sense wire can connect to any 120v source – for instance, the output of the main AC breaker. The inverter powers that and so does shore power. The question then becomes do you want to run the refrigerator on 120vac when using the batteries? Probably not. So I think you could wire it to the AC input to the inverter/charger if that's what you have. If it's only an inverter, then you need to connect to a spot where shore power comes in but is not connected when the inverter is on. I have a Freedom 2000 charger/inverter and it is inline with the shore power connector -if there is shore power it won't turn on the inverter. So that's where I'd put my sense wire, that is if I had one.
I hope that makes sense – if the inverter supplies the entire ac bus without break from the shore power cord, then you could do what Tor did, namely put a Shore/off/Gen switch in between the shore power inlet and the inverter output. That way you'd know when you're on the inverter and don't want to run the reefer on AC and when you're on shore power and do.
Bob
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Bob Fine
s/v Pelican
Pearson 424 Hull #8
http://thesailinglife.blogspot.com
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Linus
A few beers and winds would be a good deal!I had assumed that you had an engine-driven system. I was unaware that Pearson offered a 12v system with holding plates. The nice thing about an electric compressor is you can run the system without using your engine when tied to a dock. The disadvantage of such a setup is that the electric compressors are much smaller than an engine-driven system, approximately 1/10 the HP rating. They don’t consume their maximum rated load for the entire running cycle so the comparison between a small and large compressor isn’t linear. An electric compressor will still require longer running times. I’ve considered changing to an electric compressor, but I’m so rarely tied to a dock that there’s no urgency in switching over. I’ve replaced my compressor four times in the 23 years I’ve owned the boat. The last unit I installed is a Sanden rotary compressor. I hope its more reliable than the York piston pumps that I’ve had in the past. In theory, I could drive an engine-driven compressor with an electric motor. The largest motor I can run off 115v is about 3hp. That’s a small engine-driven compressor. I’d need a pretty big inverter and alternator to run something like that. For my cruising habits, I’m happy with the setup I have.
Seafrost lists a DC 5000 system for $3400. That includes a 12v 1/2 hp compressor, condenser, and evaporator without holding plates.
http://www.seafrost.com/dc5000.htmThat’s a lot of money to replace your unit if it can be salvaged. The engine-driven compressors have a drain hole in the bottom to allow you to replace the oil. I don’t know if your unit has the same fitting. It may be sealed. I’ve heard that you don’t necessarily need to replace your oil. There are conversion kits available at Walmart that adds R-134 compatible oil to your system. I don’t know if these work well.
http://www.technauticsinc.com/manuals/Retrofit%20Kit.pdfI drained the oil in my old system and replaced with R-134 compatible oil when I switched over. There are several types of R-134 compatible oil.
http://www.aircondition.com/tech/questions/49/Which-Oil-to-Use-with-R-134a%3F
Regarding your question, it would be straightforward to run down to Radio Shack and buy a 115v relay. When your shore power or inverter is on, it would close the relay. You could switch in either 12v or ground to your refrigeration system to turn it on.
Rich
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Robert
The voltage sense wire is used to sense charging voltage so that the compressor will pull the cold plates down with the full fury of the system. Once the plates are frozen or they begin to melt the unit runs for short periods so not to drain the batteries. Or that is the best that I can figure from the provided information.
Linus
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Oh, ah, well, that's a different story entirely. Nevermind. I thought it sensed the presence of 120v and ran off that or 12v if 120 wasn't available.
Oops.
Bob
On Fri, Oct 30, 2009 at 3:31 PM, Linus Martinez < ([email][/email])> wrote:
Quote:Robert
The voltage sense wire is used to sense charging voltage so that the compressor will pull the cold plates down with the full fury of the system. Once the plates are frozen or they begin to melt the unit runs for short periods so not to drain the batteries. Or that is the best that I can figure from the provided information.
Linus<.. snip>
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The sense leads (there should be two sets) are to sense oil pressure from a running engine and or shore power. The system isn't intended to be run on batteries alone. Properly wired these will prevent that.
Chuck
On Fri, Oct 30, 2009 at 3:15 PM, Robert Fine < ([email][/email])> wrote:Quote:Oh, ah, well, that's a different story entirely. Nevermind. I thought it sensed the presence of 120v and ran off that or 12v if 120 wasn't available.Oops.
Bob
On Fri, Oct 30, 2009 at 3:31 PM, Linus Martinez < ([email][/email])> wrote:
Quote:Robert
The voltage sense wire is used to sense charging voltage so that the compressor will pull the cold plates down with the full fury of the system. Once the plates are frozen or they begin to melt the unit runs for short periods so not to drain the batteries. Or that is the best that I can figure from the provided information.
Linus<.. snip>
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An alternate method to do the same thing is to put a 6V relay on your tach line from your alternator. When the engine is up to speed, it will close the relay. The reduced voltage is because the tach signal is a half-wave signal and therefore half the 12v alternator output.
Rich
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