SanFran 12 Posted December 30, 2010 Share Posted December 30, 2010 Is there any paticular reason why marine refrigeration is so expensive.... I gotta say it is something beyond me. Its all installed, just hasnt run for the last 5 years (new owner here, and previous owner hasnt used the boat for 4 years) It has all the necessary gear, Im told, and may just need new seals and regassing, so wheres the cost? People have scared me off already suggesting that might be in the high hundys... Link to post Share on other sites
Guest Posted December 30, 2010 Share Posted December 30, 2010 Not just marine Fridge is expensive. I got quoted $850 to replace the coil in front of radiator of car Aircon that had been holed by stone. Secondhand unit as well. Link to post Share on other sites
PaulR 3 Posted December 30, 2010 Share Posted December 30, 2010 The "real cost" comes from people NOT using their fridges / freezers every week especially over winter. Without use, so I believe, the seals dry out and so the gas is not pumped sufficiently so the fridge/freezer does not get cold enough as we would like. Typically this means the belt driven compressor unit attached to engine needs reconditioning = expense to take away to workshop, recondition, return to refit and the regas system etc. Further some of the release valves ALWAYS need replacing and the refigerant gas is knot cheap. So people all need to get their refrigertaion running again, in the 2 weeks of December of course. Link to post Share on other sites
wheels 543 Posted December 30, 2010 Share Posted December 30, 2010 The issue of seals drying out is with engine or externally driven compressor units. The shaft has a seal that the lubricating oil inside the pump, keeps soft and plyable and a slight film between the seal lip and shaft. If the unit is not run once a month, the seal becomes dry and hard and very slowly, gas leaks out between the seal and shaft. Fully enclosed units don't have that problem. The shaft is the crankshaft and so to replace a seal is quite a wee job. Fully enclosed units don't have that problem. Then once you get into a regassing situation, most refrigeration guys like to replace the dryer. A small cylinder in the gas line that usually has silica beads to ensure all moisture is kept out of the lines. This has to be gas welded back into the line. Regassing the system is not difficult, but quite time consuming if down correctly. And for a small boat refrigeration system, it is very important to be down properly to ensure maximum efficiency. So the system should be purged with nitrogen and then vacuum and then charged with the refrigerant. The older systems that use the old gas is a little more difficult again. The system has to have the remaining gas sucked out and captivated. Then the oil has to be changed to suit the new gas. If there is a leak in a line or cooling plate that allowed the gas to escape, then that has to be tracked down. Most often a pinhole and it can often be very hard to find. Then when found, that piece of line needs to be replaced. And then the entire process of removal anmd recharging again. So in a nutshell, it can be very time consuming. Link to post Share on other sites
SanFran 12 Posted December 31, 2010 Author Share Posted December 31, 2010 bugga! Link to post Share on other sites
PaulR 3 Posted December 31, 2010 Share Posted December 31, 2010 Wheels: Thanks for the extra technical details Link to post Share on other sites
Guest Posted December 31, 2010 Share Posted December 31, 2010 shaft seals are where the problem lies in 99% of problems with open drive compressors, typicaly they consist of a carbon face sealing against a steel face with an O ring on the shaft, what happens is the oil acts almost as an adhesive and locks these two faces together resulting in a seal spin either on the shaft( tecumseh york or femsa reciprocating) or on the actual compressor body (sanden and various other rotary types) the O ring is basically knackered at this point and needs replacing and in the case of reciprocating compressors the shaft needs polishing to remove ridging from old seal etc. Any time a system is opened the drier should be replaced. and as for expense..............talk to a lawyer and see just how money can flutter away.......Average cost of a shaft seal replace is $500>$600 depending on just how difficult it is to get to and just how neglected or just plain filthy the location is, actually getting hold of replacement seals is becoming harder as well. R406a,the most reliable replacement for R12 is also on its way out due to an R22 content and the cost of has increased accordingly, and like all "new"refrigerants is molecularly thinner that what the basic system and components were designed for so leaks appear where you least expect them. Best thing you can do with an open drive system is pop in a thermostat so everytime the engine is started the fridge runs and only runs till the set temp is reached very simple to do and saves a lot of maintenance issues such as moisture ingress via the shaft seal among others, also means the freezer can be a fridge and not freeze the beer. Another killer can be compressor speed...sub 800 rpm max......ok waiting to thear from those who say but but in cars they are rated at 6000rpm......they are.....however, working at lower temperatures the lowside of the system is at a lower pressure resulting in a lower gas return therefore a lower oil return ( oil and refrigerant circulate together) and the certainty that the comp will be working in a vacuum and not be overly happy about it particularly when worked hard during the 2 week dream period.........advanced applied physics in a hostile enviroment requires carefull initial engineering and will cost.........get over it Link to post Share on other sites
Guest Posted January 2, 2011 Share Posted January 2, 2011 There was a guy on trademe flogging off CHEAP Engel type fridges (compressor) for about $600!!!! I got one and NO REGRETS!! So far its great and comes with a 240v 12v power supply. Link to post Share on other sites
ex TL systems 63 Posted January 2, 2011 Share Posted January 2, 2011 keep it simple 12 v compressor driven engel or similiar fridge freezers have never given me any trouble and i have bought them secondhand or inherited them with a boat. A 100w solar panel will go close to keeping up with the energy needed to run one, they are quiet and efficient and you don,t have to run a motor to keep things cold.If it did pack up you could buy a new one easy enough, or take it out to a serviceman. Even the gas fridges work ok as long as they are kept level and you are careful to avoid gas leaks. Link to post Share on other sites
wheels 543 Posted January 2, 2011 Share Posted January 2, 2011 .advanced applied physics in a hostile enviroment requires carefull initial engineering and will cost.........get over it Easily spoken by someone with oodles of cash, but many of us are po....umm...Buget boaters and some of the dollars charged by some of the Refrigeration "engineers" are hard faught for. I was having a fridge discussion with a friend who is fixing up his boat at the moment. I got a cheap front loading freezer from the Wharehouse for $199 on special. I unscrewed the compressor unit and tipped the freezer over on it's back and dropped it into the place I wanted it, under a settee, with the compressor sitting upright. It has worked wonderfully for 7yrs now. So I suggested they do the same till the day came that they could afford to do it properly. They were thrilled with the idea. But you should have heard all the so called "experts" spout on about it. Of course all the experts sold and installed refrigeration also and so they all had these wonderful ideas, that yes they would have been great, but completely out of financial reach of the owners. Sometimes there are indeed ways to get around situations, even if temporary. To be honest, I really didn't think I would get 7yrs out of it. So I am thrilled. And it is still running and looking just as good as the day it went in. The worst Fridge decision I ever made was one of those three way units. $2500 worth of energy hungry fridge that keeps having the gas go out everytime the wind blows hard or we heel way over sailing. I am going to fit one of those Danfoss compressor units to it one day. Infact I have a fridge unit from a Dehumidifier that I am thinking of fitting to it. I just need a fridge thermostat and I reckon I am cooking with gas. Link to post Share on other sites
Atom Ant 0 Posted January 2, 2011 Share Posted January 2, 2011 wheels I admire you mate! Thinking of doing that is just bloody clever. You see I just would never have even thought of it! So kudos to you - I wish I was that clever. Link to post Share on other sites
wheels 543 Posted January 2, 2011 Share Posted January 2, 2011 Haha, it's amazing how clever you can be when finance neccessatates. Now, if I could only spell, I'd be brilliant Link to post Share on other sites
Guest Posted January 3, 2011 Share Posted January 3, 2011 Did you have to get it regassed after moving the compressor, or did the pipes just gently ease to where they needed to be? Link to post Share on other sites
wheels 543 Posted January 3, 2011 Share Posted January 3, 2011 The pipes eased with err....ease. The beauty of copper pipe There was only one down side to the exercise. The pipes that radiate the heat are biult into the sides of the freezer and I assume therefore the metal cabinet acts as a heatsink. My intention was to encase the Freezer further to with Polystyrene to increase it's thermal efficiency and it was by accident that I found the sides were hot as toast. So I had to leave a space around the freezer to allow air to keep it cool. This must surely mean that a certain percentage of heat ends up going back through the insulation and back into the freezer reducing its efficiency. One day when I have time, I would like to play with opening up those side panels and see if I can improve that somehow. Maybe the panel will come away and allow me to slip or pour more insulation in around the freezer part. The back of the freezer, which is now the bottom, allows a lot of cold through and I even found ice form on the back of it. So I biult that up with lots more insulation and that seems to have worked just fine. Untill we got mice on board and they decided that this was an excellent home to tunnel into and we had polystyrene balls lying in the bilge everywhere Knowing what I do now, I would most certainly do it again, but explore it a little more in making it slightly more energy efficient if that is at all possible. But sumed up, we have been very happy with it. I also makes a joke of the "marine" fridges and freezers available and the rediculous prices asked for. Link to post Share on other sites
SloopJohnB 323 Posted January 3, 2011 Share Posted January 3, 2011 Years and years ago, well decades now, I helped putting a freezer into a 42 fter. The Stainless steel cabinet was wrapped with the copper tube and dropped into a timber casing, we mixed up the foam and poured it to the gap. Unfortunately the calculations for the volume was wrong, there was foam everywhere, the casing blew apart, we tried everything to clamp the box up. Lucky there was plenty of space in the boat for the deformed box. Link to post Share on other sites
wheels 543 Posted January 3, 2011 Share Posted January 3, 2011 Also few decades ago, F&P had a little oppsie at the fridge plant. They have Vats that hold several 44Gal drums of pour n foam for the fridges. The stuff gets mixed in the gun as it gets injected in to the fridge surround. Except the fella that filled the vats with the drums poured the wrong drum into the wrong vat. The mess was huge. Link to post Share on other sites
ex TL systems 63 Posted January 3, 2011 Share Posted January 3, 2011 so do you run the converted freezer on 240 v thru an inverter with the original motor ? Link to post Share on other sites
wheels 543 Posted January 3, 2011 Share Posted January 3, 2011 Yes. You will lose a little energy in the conversion of 12V to 230V of course. Howmuch depens on type and quality of inverter. Link to post Share on other sites
Guest Posted January 4, 2011 Share Posted January 4, 2011 I have an old power hungry (hmm... was made in HUNGARY!!!.. no I'm being serious here!!!) Electrolux 3 way fridge if someone wants one? $100.Good nick and goes well but would NOT recommend running any pilot flame appliance on a boat or any where else where fuels and explosive gases are stored. They do gobbel the 12 volts though. Link to post Share on other sites
Guest Posted January 4, 2011 Share Posted January 4, 2011 arrr!!!... just looked up the spec's on it: Nominal Capacity: 35 Litre Internal dimensions: 420(w)x235(d)x340(h)mm External dimensions: 500(w)x420(d)x460(h)mm (excl handles & power fittings) 3-way Power: Gas / 240v / 12v Approx consumption: 240v electric - 1.35kW / 24hrs 12v electric - 150Ah / 24hrs Gas - 187-252g / 24hrs Thermostatically controlled on 240v Piezo ignition CFC-free full foam insulation between steel external shell and plastic inner 150 amp hours in 24 hours!!! nearly 7 amps an hour!! Should fit a generator to the missus's exercycle. Link to post Share on other sites
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