Author Topic: Archive 13  (Read 4477 times)

Richard

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Archive 13
« on: May 03, 2012, 10:05:11 am »







Danfoss BD35 with Hot Shot???   Archive 13
A service tech removed the R134a from my Danfoss BD35 system (NovaKool in a trawler) and replaced it with Hot Shot when I complained about lack of cooling. I had recently purchased the boat used. Should I worry about this? Should I evaculate the system and go back to R134a? I plan to upgrade insulation to improve system performance.

Re: Can not follow instructions.
[quote:4d82009892="kollmann"]It does not appear I am going to be able to help you any more, as troubleshooting is a process of elimination and you want to try theories. If Compressor is truly overheating there is a reason and unless corrected the compressor eventually will fail. Did the LED indicate an overload indicating overheating? Did eliminating the AC/DC unit correct an over voltage or under voltage problem? Sorry, but I give up call a Qualified repair person.[/quote:4d82009892] Richard - I HAVE been eliminating possible causes slowly but methodically because of the intermittent nature of this problem. But it seems that because the methods are not the ones you suggested, you get annoyed and say My way or the Highway. I HAVE solved the problem myself and am now OUT OF HERE. Please unregister me.

Norcold SCQT Ice Box Conversion
I have an older ('79) Catalina 30. The old Norcold SCQT never did work, so I am looking to replace it. The newer model (they call it The Norcolder) is going to run me about $600.00. The ice box is heavily insulated via "expanded foam" and when used as an ice box it seems to be very impressive in that a couple blocks of ice will last me an entire weekend. I do want to get away from the ice alltogether though. I have heard good and bad things about Norcold. Can you give me your opinion?

Cabinet Refrigerator Poor Performance
Previous E mail Cabin Temperature 100 degrees refrigerator will drop to only 60 degrees. I do not know how to answer the question about what to do about R414 in your system. Changing the refrigerant was not going to help the problem of poor performance especially a blended unfriendly refrigerant with a higher liquid pressure than 134a. When you are trying to improve performance on these small systems the correct volume of refrigerant is critical so I try not to recommend tampering with it. Have you compared how the system performs now against the previous test with 134a? In order to improve warm weather performance on these cabinet refrigerators it must be understood that they were not intended to be closed up in a boat. I could not find technical info on a six cubic ft Nova Kool but here is the performance info on their 5.5 cu. ft. refrigerator/freezer: Model RFU6200 operating at ambient temperature of 75 degrees, current draw operating on 12 volts 4.4 amps. Average current draw per day 36 amp-hrs, maintaining a 36 degree refrigerator. Things that can lower cabinet refrigerator temperatures in a warm boat cabin: Assuming the refrigeration unit cycles off at times even with thermostat is set full cold. A proper designed cabinet refrigerator will have a thermostat that when set to mid range provides the desired temperature in the box. If the ambient design temperature is 75 degrees and ambient temperature is increased to 100 degrees the thermostats full cold range is incorrect. I have found a simple way to adjust the thermostats range colder by reducing its sense tubes contact with the evaporator. I have not done this on a Nova Kool cabinet unit but on an Isotherm cabinet tube is easy to slide out reducing a third of its contact area. The condenser will be sized to match the output capacity of compressor but the airflow may be restricted by where an how the refrigerator is installed in the boat. One hundred degree ambient cabin air temperature along with exceeding the 75 degree design level could cause the condenser to exceed the 131 degrees, Dandoss performance figure. There are several way to improve the condensers cooling, Add a fan, install a larger CFM fan, baffle and guide the air unrestricted through the cabinet. In some applications it is possible to draw air into condenser area from the bilge. In the tropics I recommend a 80 to 100 cfm 12 volt muffin fans for condenser cooling. WARNING, The BD35 fan circuit will not carry .5 amp load which means changing the present fan will require a relay. There is a possibility that the BD35 variable speed compressor is not running at its highest speed. For the compressor to run at max speed 3500 RPM there would be a 1500 ohm resistor in the thermostat wiring. To find out what speed the compressor is set to run at disconnect the thermostat wires at compressor module and read the resistance in the thermostat and its wiring, The contacts in thermostat must be closed to check resistance. Door seals are another cause for a poor performing cabinet refrigerator. Even when the door seals look good they may not provide a firm contact. The door seal is to stop air infiltration and not intended to be insulation therefore the door must be mechanically held closed. Two tips check the seal all the way around with a ribbon closed in door, if it pulls out easily the seal is not good enough. These doors warp so they need mechanical latches at both the top and bottom to insure a good tight fit.

Adler- Barbour with a BD35F comp.? or another brand?
Mr. Kollman, I have a very small box with very good insulation (3 cu. ft. - R,30) I had wanted to use an Adler-Barbour CU-100 cond/comp. with a VD-150 vertical evap. but a BD35F comp/cond. would be better sized for this installation. If I could get someone to install a BD35 comp./cond. in this unit would it work? The dealer I am using wants me to buy a Waeco CU-85 comp/cond. with a VD-09 evap. but they say I wont be able to mount it to use vertical ice trays! I can't understand why not. Perhaps I'm dealing with the wrong refrigeration "professionals"? What do you think my best option would be? Thanks, Bill

Update III
Richard, Per your instructions I have done the following: Disconneted fans. Attempted to start under ship power. No start, module beeps. No motion felt inside the compressor. Wired directly from 12V battery to control module (fans disconnected). Multiple start attempts do not start. About the sixth start attempt compressor starts. Did a couple of shutdown/restarts and the compressor started. One time it started then stopped after five seconds. Wired back to ship power. No start (beep) in several attempts. Wired back to direct 12v. No start in several attempts. I did monitor the battery voltage on startup sequence and it held at 12V. Note however the module had beeped well in advance of my meter reaching full scale. I did call Miller Marine whom repaired my control module last year. The technician believed the problem was in the control module. He also stated that it is almost impossible to kill the BD compressors. Peter

Norcold for Cat30
All icebox refrigeration conversion systems have good points and bad points. The Norcold is a very good unit for the right application. I do not know the size of your icebox but if it is less than six cubic feet the Norcolder single compressor conversion unit will defiantly provide equal or better cooling than ice in California. If your box is three cubic feet the Norcolder will turn the box into a 33 degree refrigerator. Disadvantages of Norcolder: It is for small well insulated boxes. Most service technicians do not like to work on them as they are difficult to repair, because the unit condensing unit must be remover from boat to repair. Replacement parts not easy to find. Advantages: Cost less than others. AC and DC powered will reduce battery stress when connected to shore power. Service life of compressor possibly 20 years. System reliability exceptional. Many units still operating after 20 years. Outstanding energy efficiency in the right size box.

Old BD troubleshooting
The new BD compressors eliminate all of the time consuming trouble shooting with the programed LED signal. I agree with Miller Marine its time to repair the module again. Your unit is too old to spend $200 on a new module. One other option might be to ask around many of the old systems are being replaced because of R12 refrigerant phase out.

BD50 or BD35
Because you boat is in Florida the Adler Barbour CU100 and VD150 is a good choice as long as the resistor at the thermostat is removed. When the speed resistor is removed the compressor will slow down from 2500 to 2000 rpm. There is a test boat in my 12 volt book of a box comparison much like yours, CU100 Condensing unit and VD150 evaporator. Test conditions 82 degree seawater and 85 degree air temp. Box temperature 40.1 to 41.9 degrees for 21 hours. Total amp-hours consumed 21. Freezer Bin would have been much colder than box but was not recorded. In looking at the efficiency charts in my book with ambient air temp at 80 degree the BD35 at slow speed could reduce the daily amp-hrs further. Unless you are planning on moving boat up north or to California I would stay with the BD50 compressor There are other companies that do offer vertical evaporator bins the size you want with BD35 compressor, but you would need to buy the ice trays from AB. Other companies, Grunert, Electricboat, Nova kool, EZ Kool.


Thank you for all your help Mr. Kollman. I am now planning to use blueboard as you suggested. I will also order the A-B unit. Even though I could reduce my amp hours with other brands I will feel better about the quality with the Coldmachine. This fall after the install I will let you know my results for your data base. Thank you, Bill

Norcold Refrigerator
Mr. Kollman, I have a small front-loading Norcold refrigerator on my powerboat. It has been working fine until last week. Now, the unit starts and I can hear it running, but the evaporator plate only gets cool to the touch. However, the capillary tube at the back completely frosts over very quickly with a thick layer. What is going wrong? Regards Peter

Norcold Troubleshooting
There are only two reasons for frost at the end of capillary tube and no frost on complete evaporator. There is a refrigerant leak or the condenser is not disposing of heat. To see if refrigerant is low feel the condenser coil if it is only slightly warm then there is a refrigerant leak.

Freezer-to-Reefer Conversion by thermostat
I have a NORCOLD TEKII DE-351D on my flybridge and want to replace it with a similar-sized unit freezer that will, by simply adjusting the thermostat, convert to a reefer. When we're cruising, we need the freezer; when we're near our home, we need a reefer. Is this possible, and, if so, what unit is recommended? The NORCOLD is dual-voltage, but that's not important since we have a large inverter. Thanks,


I do not know of a company that has a built in cabinet convertible refrigerator freezer but there are portable top loading units from Engel, Norcold and maybe others that will serve either purpose. Depending on the outside air temperature and the boxs insulation, any refrigerator can be a freezer if the thermostat can be set to a freezer temperature. Example; The Engel 45 thermostat has a temperature range from +40 degrees to 4 degrees F. using the same compressor as your present unit. If your units thermostat has only two wires connected to it and the boat is not in the tropics it may be possible to change thermostat and have both refrigerator and freezer. Finding a freezer that will fit in your present space will be difficult. Here is a small 110 volt I found on the web, copy and past complete address. http://www.compactappliance.com/xq/JSP.detailmain/Avanti_Upright_ Freestanding_Freezer___3_2_Cu__Ft_/itemID.8346/itemType. Product/iProductID.8346/qx/shopping/product/VM31W.htm?mtcpromotion=Kickers>Freezers>Avanti%20Freestanding%20Freezer>4

Freezer-to-Reefer Conversion by thermostat
Thanks for your reply Mr. Kollmann. Can you pls point me to a supplier for a 2-wire thermostat such as you mentioned? Thanks,


why didn't you just call them about it?


The extra tubing is coiled outside the box near the compressor. There is also a length of insulation over the tubing that belongs just outside the refrigerator box. The tubing can be wrapped together in a 10 to 12 inch coil. The only thing that needs special care are the line connections. Adler Barbour's pre-chraged current connector fittings are self piercing. To prevent refrigerant loss they must be in a straight line before attempting the connection. When the fittings are lined up correctly the o ring will hold back refrigerant while the fitting is tightened. Once the connector is tight a metal seal will hold back the refrigerant for the life of system. Be sure to follow the manufacturers installation guide.

which book to buy?
I'm a boat owner, going long term cruising and would like to buy one of your books. I'm pretty handy can do most things with a little instruction, I don't know which of your books to buy? can you advise please. thanks in advance, Jim

Which Book
The Do It Yourself third edition book released in 2000 mainly covers the larger more complicated boat refrigeration systems, engine driven, 110volt and the older Danfoss 12 volt compressors. When the improvements to 12 volt boat systems occurred in the late 1990s I begin consulting on their repairs and tested the new systems. Information collected totaled over one hundred pages and was too much to add to the DIY book so I published in 2004 the 12/24 Volt Boat Refrigeration Manual. If you are a mechanic wanting to do refrigeration work for others you would need both books. A cruising boat should carry maintenance manuals on all onboard equipment if possible, as many problems can be taken care of without a mechanic. It you have one of the better new 12/24 refrigeration systems then you would want the 12/24 volt manual only. Many of the actual problems encountered with these small 12 volt units are detailed in this manual. You can review the table of contents for both books on my web site. The internet today allows me to provide assistance almost daily to people all over the world who have bought my books. Do you know of any other author that has provided this free service for over twenty years?