Author Topic: Archive 8  (Read 3306 times)

Richard

  • Administrator
  • Sr. Member
  • *****
  • Posts: 324
    • View Profile
Archive 8
« on: May 03, 2012, 10:21:56 am »

Archive 8

refrigerant low
I'll wait to get and read your book before I go any further. Many thanks for your help b. kaye


I have a Cool Blue as well, probably a 2000 model or so. It works great and I have seen as little as 20 amps per pay, and as much as 100 amps. (I have an hour-meter attached to the electronic control: with the thermostat set at 1, it runs 3 hours per day, at max setting it will run 24 hours a day) With ice cream and steaks in the freezer I keep it running as much as I can without running down the batteries. (It takes about 80 to 90 amp hours to maintain -15 Celsius for my ice cream. Not sure what that is in F, I am a metric kind of guy and have the thermometers in the both boxes set to C.. The coldest I have ever seen the freezer is -18 C with the probe half way down the box) At any rate, I agree with Mr. Kollman, check the thermostat. That being said: I could not get my comressor to start a couple of times so I suspected the thermostat was wrong, disconnected it and hot-wired the cables so the unit would whenever the breaker was "On". Well, hell, when I get back from the Bahamas, I will spend a $100.00 or so on a new thermostat I said to myself. (Sitting for anchor in the Exumas, sipping ice cold beer and enjoying life. we were. Once in a while we use the SSB radio and turn the breaker for the fridge OFF to avoid the interference, when switching the breaker back on, it would not start the fridge, hence I thought we had a thermostat problem.) I pulled out Mr. Kollmans book and started reading up on thermostats: Found there was a time delay in the thermostat to let "the pressure drop". Huh, did not know that one. Went below and hooked up the thermostat again, and sure enough, it worked fine. Thank your Mr. Kollman, your book saved me at leat $100.00 on a new thermostat, and perhaps $1,000.00 for a new compressor as I would have kept operating with the circuit breaker to OFF for 5 minuttes, then ON again if I had not read your book. All in all I am very happy with the Cool BLue and the performance and relability. Going on 5 years and 7000 hours. Highly recommend the optional "BIG" holding plate, 2.5" instead of 1". I have described my system in more details somewhere else on this forum, search around using "Cool Blue". Thanks again Mr. Kollman for writing a very, very good and helpful book. Sincerely Dag Hanssen S/V "Rhapsody" , 1979 CSY 33 Cutter, hull # 19

Thermostat Problems
Tom, CSY Mon has a good point if the compressor is stopped and restarted too quickly it will be under a high pressure overload and the start will be rejected by its electronic module. Then after several seconds it will automatically try another startup. All hermetically sealed refrigerant compressors for refrigeration and air conditioning need a short rest period between run cycles to allow the pressure in the system to equalize. The thermostat controls the off cycle by temperature differential not time. The preset differential in these small mechanical thermostats is from 6 to 10 degrees, this then provides enough time far compressor pressures to equalize. A replacement thermostat is available for under $15 at Rparts.


Dag and Mr. Kollman, Thank you for the information. I will order the new thermostat this week and see if that will do the trick. I do have the 2 1/2 thick plate and it was working fine. I also have another fridge with an Adler Barber unit running so I need to stay at the 25 - 30- amps / day on the Coolblue. 100 amps for the Cool Blue and 50 for the adler means big daily draw. I'll try it and hope the thermostast is the solution. There are still bubbles in the sight glass. Should I add some R-134? AS Mr. Kollman has stated since the unit cools to - 13 F on the plate the unit seeems to be working....just too much as ice builds up pretty thick.. One thing at a time I guess..I'll get the thermostat. I looked at R-Parts. Is it a digital unit? I did not find the $15 unit. Thanks, Tom

Thermostat
I would not mess with refrigerant charge if the unit performes OK, Less is better than too much. For replacement thermostat, Go to Rparts Catalog < Controls click on 015 0282 for picture. Rparts $14.95 015-0282 Refrigerator Thermostat Range: +38 dgr. F / +10 dgr.F Differential: 12 dgr. F

BD80 Hermetic vs belt drive DC compressor
I plan to build a 15 cu-ft trailer mounted refrigerator/freezer for use in the desert (4 cu-ft freezer and 11 cu-ft refrigerator). My concern is the ability of the refrigeration equipment to survive a 40 mile drive on washboard roads without damage. My calculated heat load is about 6000 BTU per day. That may look like a low heat load for desert conditions but the reefer box will be enclosed in a larger box that is swamp cooled so it will never be exposed to sunlight or to air that is warmer than 80 degrees. I am also able to use swamp cooler air for cooling the condenser. For the above heat load and an evaporator temp of 0 degrees F, I think the Danfoss BD80 could do the job running flat out around 50% of the time. An alternative would be to use a small Bitzer open drive compressor with DC motor and holding plate. That system would cost a bit more but perhaps would work better because the compressor could be shut off for the 2+ hour drive down the washboard. My questions: 1) Is there a problem with either of these systems operating while being subjected to lots of vibration? I know these systems get some heavy shocks in a boat but not being a boater, I have no idea how vibration and shock in a boat might compare to the shock of driving on washboard. 2) Would the BD80 running at high RPMs be likely to use more or less electricity per day vs the Bitzer compressor with one of the Glacier Bay motors and a cold plate? Any comments or suggestions welcome. Thanks

school
Do you have a school to teach basic refrigeration repairs ? I recently attended a school for Yanmar diesel engines and it was really excellent. A basic course in understanding how it works and then basic repairs for the boat owner would be very useful. bj

backup system
I have a 220 50 hz refrigeration system on my catamarran and would like to put in a backup system..preferably a 12 volt system ..as that could run off my battery bank ,a 1200 amp bank. Is it possible to use the same cold plate and just "T" it into the present system as I only have 1 circuit in my cold plate. It is a 2 box system with freezer on the bottom and fridge on top with air circulation to top..they are both about 6 cubic feet..

Final update
It's been a while since I first wrote about my old Adler unit not working, but I wanted to post the final results. After going through all the toubleshooting steps given here, it was correctly judged that the electronic control module was the problem. Frigiboat makes a replacement controller for the BD-35 compressor, and I purchased one through Great Waters Marine for $200. The folks there at Great Waters are very helpful and competitive in their pricing. Anyway, my frig is frosty again, so thanks for the help.

Refrigeration in the desert.
I dont know how you came up with a heat load of only 6000 Btu for a 15 cu. ft. refrigerator/freezer a day. I would think that 24000 Btu a day would be more realistic if the product inside were pre-frozen first. A refrigerator inside Swamp Cooler (water evaporative cooler) sounds interesting but I would want to over design insulation and system capacity. As far as I know Swamp Coolers can only drop temperature twenty degrees and I thought the Desert got to over 120 degrees. I dont know what the effects of washboard roads will have on compressors. I can only guess that the larger shaft driven compressor would be better than the small sealed compressor. Sealed compressors are mounted on springs inside the canister and high impact rapid shaking will cause compressor assembly to contact canister, pick one up and shake it to see what I mean. Another problem is the BD compressors tend to shut down at ambient temperatures of over 105 degrees do to overload.

Boat Refrigeration Training
The closest thing to a training program on booat refrigeration is my Do it yourself book and 12/24 volt Manual. These books have been used to train charter boat people.

The Making Of a Hybrid
The best answer to your question would be to keep the present system intact. Then install one of Sea Frost's new two thin plate BD80 compressor systems in the same box if there is room even if the new plates were on top of old plates.

Get Rid Of My 110v system?
[b:57921e1e50] :? Thinking very seriously about ditching my 1/3hp 110v system, with three "leaking holding plates" for a Cool Blue system. My box is 3'x3'x22" but tapered to 6" at the floor level. With 2 top lids and one side door. Just to let you know I have a Vagabond42. The original system was made by Spa Creek back in 1982 with an engine driven system. I given up on the engine system years ago, Richard even with all of the help and parts by you. It was that old Ford compressor. Luckily I have a genset that has made it possible for us to survive 3 winters in the Bahamas. We have tried everything to seal the holding plates but some demon must come and steal away the 60/40 mix that you recommend in your books. So now we are biting the bullet to go 12 v. completely unless you say otherwise. We have a good 4 - 5" of insulation. The freezer will be about 1/4 of the box with a divider with the recommended spill holes. We will also go with the 2.5 inch holding plate. But I was wondering about the 4" holding plate. What are your thoughts about this system and should I use $" or @.5" plates and do I get rid of the 110v system. Also, should I build a lid over the freezer section with the plate just below the new made lid along with the originally top lids? Thanks, and your books made it possible for me to do 8 months x3yr in the Bahamas. Your talks at the SSCA rallies are great![/b:57921e1e50]


Mr. Kollman, Rparts is out of the refrigerator thermostats, they do have the freezer stat and that is how I use this unit. It's a freezer with a separator and the adjustable opening to vent cold air into the other side for drinks etc. The freezer unit is: Range: +17 dgr. F / -13 dgr.F Differential: 16 dgr. F Is this what I need? Thanks, Tom

Thermostat
Yes, The freezer thermostat will work in your application. If the box is too cold with thermostat set to lowest number increase the thermostat capillary tube's contact with cold plate.

Engine drive to 12 volt refrigeration
I feel that I must point out that you may be spoiled with your present units Btu capacity. Switching to 12 volt refrigeration may require a major upgrade to the boats DC power grid to produce the same results. Large 12volt icebox conversion refrigeration units are available direct drive or belt driven. Normally these large units require the engine to be running when they run, and are not as reliable or maintenance free as the smaller sealed air cooled units. I believe your box to be around 11.5 cu ft, therefore the Cool Blue is too small for your application. My recommendation is that the best 12 volt system for that size divided box, cruising in warm waters, is a BD80 compressor with AEO speed control and twin plates in freezer section. Sea Frost is currently the only company offering this unit. Check their web site they even offer custom plates that maybe necessary to fit your tapered box. It you have further questions or need help let me know.


[quote:95471961a6]just too much as ice builds up pretty thick..[/quote:95471961a6] You mean the rime-ice that builds up on the holding plate from moisture in the air..? I have tried to spray PAM on the plate. (cooking grease in a spray can) It seemed to slow the accumulation of ice build up. Can you recommend a better product for stopping or stalling the build up of ice Mr. Kollman...?

waeco icebox conversion - intermittent start
WE have a NEW Waeco Coolmatic icebox conversion unit that we installed earlier this year. This is the unit: http://makeashorterlink.com/?E12D2627D This unit uses the Danfoss BD35F compressor & controls. Unit is in cupboard, but is well ventilated with 12v computer fan to help exhaust hot air. Yesterday, cupboard was at ~97F. Box is about 4 cu.ft. and has fair to good insulation - as much as can be added to outside of original box. Installation has an optional Mobitronics AC power supply. When 110VAC is present, solenoid switches from battery (12v DC) to 24VDC which is apparently OK! This unit puts out 24V with 110V input - Spec says nominal output voltage is 25V and no-load voltage is 29V. The unit is purpose made for the BD35 compressors which, according to manual, are apparently capable of dual voltages. PROBLEM: This weekend (it was cool ~65F), the compressor would not come on for long periods (on AC or DC) - box temperature would rise from 38F to 48F or so. Eventually, just when I thought the unit was completely dead), it would kick in and run again. Nothing I did such as switching unit on/off or rotating thermostat knob to different settings would cause any reaction). I need to retest, but it later seemed to work properly when I ran it on DC only (no simultaneous charging or AC). Previously, the unit would cycle about 50% on and off and maintain temperature in a narrow band. Only change that I can see, is that the batteries were fully charged last night and we were at a different dock (for AC). It was also quite cool. The Waeco manual says: 12v Cut-in voltage 11.7V Cut-out voltage 10.4V 24V Cut-In voltage 24.2V Cut-Out voltage 22.8V Distance from batteries is about 10 ft. (direct connected via 15A breaker/switch) Wire size is 8ga except for Mobitronics unit which has short leads of lighter wiring (about 1ft in/out) House bank is 2x6v for 200AH and new. Charger is Truecharge 10. Combiner is Blueseas ACR to 12v starting battery. Do you think it is possible I am getting cutout due to too HIGH a voltage? I don't suspect too low, because I have run unit mostly with undercharged batteries with no problem. I did measure voltage at Refrig terminals (unit not running) but with charger on and it was about 12.7-13V) - I forget 24V number, but I think it was something like 25.2V. I read about using a LED for troubleshooting - But my notes say there is already a light blue wire connected to the D terminal - can't recall where it leads. Any suggestions appreciated - especially on how to properly test unit so as to determine if controls are functioning properly or not. Graham


Thanks for the reply on rec.boats.cruising. This is the response I posted there (edited): Low voltage is unlikely because batteries were freshly charged - could be a bad connection somewhere - I will check. But, perhaps high DC voltage is the problem? I will check this by turning something on until voltage is within range. High/Low voltage when on Mobitronics AC unit is, I suppose, possible if an input range of say 110-120v does not result in 24V within the cutin/out range. Fan circuit overload is possible - I added some insulation above unit - maybe something dropped into fan - I will try vacuuming. I will also try disconnecting the fan. I will also try and get an ammeter installed - I don't like the idea of adding more connections though - Maybe I can get a clamp on type. Funny thing though, once unit does start, it keeps running until temperature is at setting, so you would not think there could be an overload? I would like to use LED diagnostics - But not sure what light blue wire presently connected to "D" does. Maybe there is an LED already there somewhere?