Author Topic: Archive 4  (Read 4031 times)

Richard

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Archive 4
« on: May 03, 2012, 10:42:41 am »
Adler Barbour Poor Performance      Archive 4
I am sure there are answers to why your Adler Barbour is not producing the results you want, but before I can offer help I need more information. General comment, I am assuming when you say cold plate you are referring to ABs Power Plate that is 19 in. by 11 inch. I am also assuming the plate is mounted off the wall on stand off posts? The surface area of these plates is too small to transfer maximum amount of energy produced from the Danfoss BD compressors. A better choice for the evaporator would have been the thin plate with more than double the heat transfer surface of a power plate. A fan in freezer will help move more heat into plate but I dough this is a total solution. It may be the refrigerant process in the plate is not efficient enough. Even if the plate is not transferring enough heat the compressor should cycle off and on, because on this unit the thermostat is operated by the temperature of the plate and not box temperature. Water air/cooling on a SCM when in warm waters of the tropics is not as efficient as, air cooled only would be. Have you tried a day with the pump turned off? This is as far as I can go without some answers to my questions. Describe what you mean by 6 psi of suction pressure and why it was necessary to connect a gauge to the system? Did you purge the air from gauge set before connecting it to service port? Was the system running when gauges were connected? What was the temperature in the plate and in the box at the exact time when the gauge read 6 psi? Does your suction gauge read zero when not connected to system? What is model number of compressor, BD2.5, BD3, BD50? Describe the location of compressor and what prevents the same cooling air from passing through it again? What refrigerant is in the system? Has anyone added refrigerant? It you have a BD 50 compressor look at the cover over the thermostat for a part number as it will confirm it is for a freezer and identify the set compressor speed? Do you have a actual amp draw reading of this unit? Have you vacuumed the air intake side of condenser? If this is not a new BD50 the fan must be remover to get to dirty side? Describe all areas where frost is present and measure the amount of line outside the box with frost on it? With answers to the above I will ask you to run a test or two, and then I will make recommendations. If the only system you have is this 12 volt unit then the book you need is my 12/24 Volt Refrigeration Manual. It can be ordered from my web site at http://www.kollmann-marine.com

more info on my system
The following pertains to my system per your request for more info. Btw, thanks for an excellent site which I now wish I had seen sooner! I did discover this morning that a previous do-gooder coated the phone plug contacts for the thermostat with silicone grease. This may be what is preventing the unit from cycling. This is probably destroying my efforts to charge the unit correctly too since a frozen plate won't evaporate much liquid. I did purge the gauge line before conecting it to the unit. The reason that I put the reefer gauges on the unit was that the AB tech said that my problem was probably low charge and that field technicians charge the units to 8-10 psi suction pressure. The plate was frosting prior to this so I probably wasted my time and some 134a. I did this and after several hours the suction line began to frost al the way up to the diaphram device at the compressor suction I mentioned in my earlier post (Btw, the AB tech could not identify this device for me). I then slowly bled off the charge until the frost cleared. I am a retired marine engineer and as mentioned previously, I do have experience with large reefer systems but not much on the small, hermetic stuff and none before this on cold plates. I would apprecite a better method for charging this small unit w/o a metered charge dispensor. The unit has never been empty of refrigerant. Compressor unit: BD 50 mounted in a large, well ventilated area. Fins have been vacuumed. Air and sea temps are about the same now so I'm not optimistic that condensing medium is the issue. Refigerant: R 134a Cold plate: AB Power Plate mounted on standoffs horizontally high in the box. Plate frosts up 100% Thermostat: freezer type per AB manual (I'm in the library and didn't write down the nomenclature but it checks out). Current draw: 5.5 amps I'm going to t.s. the thermostat this afternoon. Thanks again for your help and a great site. -Mark Zalenski

Substituting a Capillary Tube for an Expansion Valve
I need to make up a capillary tube to replace an expansion valve on an old custom made system. The system has a BD3 compressor, air cooled condenser, and 2 gallon holding plate, acting as a low temperature refrigerator (not freezer) with R-12. The "12 & 24 Volt Refrigeration Manual" suggests a tube 0.025 at 97 inches, but I am not sure whether this is with R-12 or R-134a refrigerant. Any guidance would be appreciated.

AB Performance
Abler Barbour provides a small amount of grease to apply to the thermostat phone plug. This appears to be the same as NO-OX-ID a Special Compound used by phone company to keep moisture out and will not prevent current flow. The maximum current in this circuit is 5ma when compressor is running at 2000 rpm. There is no device that looks like a diaphragm in the suction line, there is only a pre-charged line connector one on each line at the condensing unit. The correct suction pressure of 8 to 10 would have been with a warm plate and only in a time window of 10 to 15 minutes after start up. Any pressure after 15 minutes is not relevant to this method of adjusting refrigerant level. I dont know what you mean the thermostat checks out, a current of 5.5 amps and a box that is not cold enough only means the compressor is running at reduced capacity. I needed the information off the thermostat cover. A well ventilated area for condensing unit may not be good enough. Place a thermometer to measure the air temperature in front of the condenser coil, but dont let it touch the coil. If this temperature is above shaded ambient temperature this could also be a problem. Your original report was compressor runs all the time and freezer temperature only drops to +26 degrees, what is the refrigerator temperature? What happens if the water pump is turned off all night and only fan cooling is used. Please reread my earlier comments on troubleshooting a system this must be a step by step process of elimination.

Sizing Capillary tubes
I dont know why you want to replace expansion valve with a Capillary tube especially on a holding plate but I would think the receiver should also be removed. I spent six months determining the correct length of cap tubing for a Danfoss BD2.5 connected to various size holding plates. I sold many a system with BD2.5 compressors connected to 0.025 at 97 inch cap tubes and holding plates as large as five gallons. When the BD3 incorporating 134a replaced the BD2.5 I found that the same size cap tube worked fine. The secret was to hold the supper cooling wrap around the suction line to between 10 to 13 tight wraps, this seems to reduced the liquid pressure into the R12 refrigerant range. The chart in design section of my 12/24 volt book page 80 provides Danfoss cap tube sizes they recommend for standard evaporators with air cooled condensers. This chart also lists cap tubes for small air cooled units based on compressor output and desired evaporator temperature ranges. Remember a holding plates solution will require an evaporator temperature twenty degrees colder then the solutions freeze point. I know of no way that a capillary tube can be accurately sized for a water cooled BD compressor on a boat and Danfoss provides no data for water cooling. The problem with water cooling is there is no way to avoid its extremes below 70 or above 80 degrees.

Deck mounted ice chest conversion
I have both of your books which have led me to the desire to convert the factory ice chest (deck mounted) to a deck freezer. I was out on a 2 week trip and thought I would keep things frozen with dry ice. Well it lasted 2 days, if that. This past weeked I thought I would investigate the ice chest a little. I was able to remove the liner and found nice, new, and dry, polystyrene (blue/pink) board, 2.4" of it, all the way around. The problem, however, is that there is either 1/4" or 1/2" air gap between the insulation and the liner -- a big NO-NO. No wonder why the dry ice didn't last long :shock: . What I am planning on doing is replace the board so that the thickness is to the point that it makes contact with the liner and seal the liner in. This will only provide a mere 2.75 inches, at most, insulation. Not very much. What I need help with is to determine whether or not to use a Holding Plate or a 'dry plate' evaporator for a freezer. Inside dimensions of the box are approx 27"w x 25" h x 9" d. or 3.6 cu-ft. I would also like to change the existing fridge system out so that it is only a fridge (no ice box evaporator plate) -- another 3.5 cu-ft. Cruising grounds are PNW, generally fresh water river. Lots of DC (458 Ah house battery) + 2.5kW inverter No generator. Thanks in advance

more info regarding my freezer refrigerator
The thermostat no. is C1502JR1500 (the factory manual says this is a freezer range control). Air inlet temp is 76 degrees. I have been running the unit on air cooling only for 6 hours. Freezer temp is 30 degrees. Refrigerator temp. is 60 degrees. Cold plate surface temp. is 14 degrees Current draw is 8 amps. There is no external box sweating. Suction line is frosted all the way to the device that isn't there:) (I'll send you a picture of it if you're interested). The box is 7 cu. ft. total with a 3/4 in. plywood divider (now lined with 3/4 in. RMatte) creating a slightly larger refrigerator space. There is a gap of 1/2 inch at the top of the divider to act as a spillover, I guess. I must emphasize that I didn't build the unit and have only owned the boat for 3 weeks. I sold an outstanding Engel portable because this freezer's cold plate got cold during the sea trial but I never pulled it down--live and learn. The AB refrigerator in the galley works fine and was supposedly done by the same outfit but I don't know who that is and at this point I guess it doesn't matter. I haven't run the unit continuously on air or water condensing for more than 24 hours because of battery considerations--if the unit can't pull down to the point that it cycles on and off I can't afford to use it this trip anyway.

AB Performance
Knowing what thermostat Adler Barbour shipped and was actually installed on your unit is important. We now know that the 1500 ohm resistor size can produce max output and compressor is running at 3500 rpm. Inlet condenser air temperature of 76 degrees is very good. This unit performs best when condenser air temperature is from 70 to 90 degrees. A thirty degree spread between freezer and refrigerator is good and shows divider insulation separation is adequate. The following reported readings indicate an incorrect refrigerant charge or contaminated refrigerant: A plate temperature of only 14 degrees after a 6 hour run with compressor running with no off cycle. Current draw of 8 amps is excessive, at 3500 rpm the BD50 without the pump running and 76 degree cooling air will draw less than 6.5 amps. Excessive frost on suction line indicates cooling is not occurring in the plate where it should. Your box size and amount of insulation and efficiency of compressor condensing unit is not preventing plate from reaching a much lower temperature. Yes, I would like to see a picture of the object in the suction line. Recommended corrective action, Remove enough refrigerant to bring frost line back up suction line to within a few inches of outside of box. Run compressor at least four hours and check plate temperature. if it drops below 14 degrees run it longer to see if it will cycle. Even if the plate temperature drops and compressor cycles off dont expect the box temperature to drop until the compressor cycles several times maybe 24 hours later. If lowering refrigerant level does not get plate temperature to the point thermostat will cycle off, then the refrigerant is contaminated and the system needs to be evacuated with a refrigeration vacuum pump, and then re-serviced with 134a. I have seen this condition before when a different manufacturer shipped a evaporator assembly with test nitrogen in it instead of pre charging it with refrigerant.

Eureka, it works!
I blew off some of the charge this morning and the plate pulled down to 8 degrees (as measured with a Home Depot indoor/outdoor electric thermometer). The thermostat cycles fine. High side pressure is only around 100 psi. Current is around five or six amps now (hard to tell with the sun going in and out). I did increase the inlet/outlet air separation by using a solid RMatte baffle shaped around the inlet of the fan. Now cool air is drawn from the bilge and hot air is exhausted up and out with no possibility of re-mixing. Thanks for emphasizing this as I will save an amp on the water pump most of the time now. My union brother Andy, a retired chief engineer, identified the mystery device as a suction screen which makes sense. I borrowed his vacuum pump and will probably evacute the unit anyway to get a fresh start since I don't know who might have serviced the unit previously. Lester at AB told me my unit plus cold plate takes 110 grams of R134a. Thanks again for a great site and your indulgence with my learning experience. Mark Zalenski

Convert Cooler To Freezer
A cooler with less than three inches of insulation especially Polystyrene is not going to be a low temperature freezer although it will keep temperatures around +22 degrees F. in a cool climate like where you are in the PNW. Holding plates serve only one purpose and that is to store excess energy when energy is not available 24 hrs per day. A holding plate in your application would be a mistake, what you need is a U shaped thin plate evaporator that surrounds the frozen product.

Size of return air hole in spillover system
Could you please clarify for me the proper size of the return air hole, at the top of the freezer box, in a spillover system? I know that a one inch opening is mentioned, but I'm not sure if that means a one inch square hole, or a one inch slot across the top of the freezer wall that connects to the frig (i.e, the freezer wall stopping one inch from the top of the box). Thanks so much for your continued help and patience. :wink:


Not an expert on the subject, but my 1" round hole on top of the divider wall seems to do the trick. On the bottom I have a 2" hole with a "door" I can close. The door is open when I load up with warm beers. After the beer-cooldown, I close the door and a good temp is maintained. Really a simple system that seems to work. My fridge box is about 5 cu/ft and the freezer is 2. Cool Blue compressor with the optional 2 1/2" cold plate.