Author Topic: where do I find a "freezer" thermostat for my Adler Barbour...  (Read 5551 times)

denogail

  • Newbie
  • *
  • Posts: 11
    • View Profile
where do I find a "freezer" thermostat for my Adler Barbour...
« on: November 10, 2014, 04:08:57 pm »
I know this probably has been asked by other, so forgive me.  I see over on the rparts.com web site that they have for sale a "freezer" thermostat that will bet the Adler Barbour colder, for a freezer configuration.  Is this just a change in the resistor value in the TSTAT itself, or is it a different sensing tube.  I would like to get it colder in there, and extra run time is OK.  Is it true that if I just change the resistor value to make the compressor run faster, will only make the box get cold...faster...but not colder?

If I do need a different TSTAT..what do you recommend?

Dennis

Richard

  • Administrator
  • Sr. Member
  • *****
  • Posts: 349
    • View Profile
Re: where do I find a "freezer" thermostat for my Adler Barbour...
« Reply #1 on: November 17, 2014, 10:50:17 am »
The thermostat’s temperature sensing small tube controls evaporator temperature and has nothing to do with compressor speed. Compressor speed is controlled by resistance of thermostat wiring and has nothing to do with thermostat itself. There is a series of numbers on paper decal, on thermostat’s plastic cover identifying size speed resistor in wiring.  Do not mesh with speed resistor your problem is temperature range of thermostat it is probably set for a refrigerator temperature and not a freezer. Presently there should be 5 inches of the sense tube clamped to evaporator. If you reduce the sense tube’s contact with evaporator to only 2 inches of tube touching evaporator this may solve your problem, if not buy the freezer thermostat from RParts.

denogail

  • Newbie
  • *
  • Posts: 11
    • View Profile
Re: where do I find a "freezer" thermostat for my Adler Barbour...
« Reply #2 on: November 17, 2014, 08:00:57 pm »
wow...Richard, I did not think of reducing the amount of sensing tubing touching the evaporator...that will be easier and cheaper for me to do.  I do have the sense tube formed in the "U" shape, as recommended in the install lit. thank you for the info.  I will do it tomorrow, and let you know.

DenO

denogail

  • Newbie
  • *
  • Posts: 11
    • View Profile
Re: where do I find a "freezer" thermostat for my Adler Barbour...
« Reply #3 on: November 19, 2014, 09:30:05 am »
OK, Richard...I removed the sense tube, and put a smaller "U"..about 1/2 the normal recommended size and reclamped it.  This did in fact lower the temp a few degrees.  I will wait for 24 hours, to see what the final temp settles into, as the 2.3 CUFT freezer is loaded to the top with meat.

Now, my next question, to the expert is:  Since I have 2 evaporators (2 complete systems) running in the box, the bottom evaporator probably will never turn on.  In case you are confused, I installed two evaporators, when I built this freezer, thinking that one would not handle the load.  I drilled out the pop rivits on the top evaporator, to remove the bottom plate.  So, picture one evaporator sitting on top of the other. Well, that really wasn't a question...but here is the question.  Is there some way that I can tie one TSTAT to run both units.  I am thinking it would be nice to have both compressors/evaporators turn on and off at the same time.  Other wise, the bottom evaporator, as mentioned, probably will never turn on, unless there is a failure in the top unit.

I hope I have explained myself..what do you think...DenO

Richard

  • Administrator
  • Sr. Member
  • *****
  • Posts: 349
    • View Profile
Re: where do I find a "freezer" thermostat for my Adler Barbour...
« Reply #4 on: November 19, 2014, 01:33:16 pm »
Deno, As I understand it:
There are two independent complete Adler Barbour Systems Yes or No?
Are both Adler Barbour units the newer models with their stainless steel box having fuses and troubleshooting LED? Yes or No?
There are two separate thermostats Yes or No?
Are both unit’s power wires and ground wires separate all the way to battery plus and minus busses?

Are you saying that the test you ran did cycle compressor off without reaching desired box temperature with only two inches of sense tube touching evaporator? Next test should be done without any of sense tube connected to evaporator. I have an Adler Barbour test unit running with refrigerator thermostat sense tube not connected to evaporator in a controlled 80 degree test area. It cycles off at a box temperature of minus 2 degrees F.

It is possible to operate both units from one thermostat by adding a simple relay but I need the above information.



denogail

  • Newbie
  • *
  • Posts: 11
    • View Profile
Re: where do I find a "freezer" thermostat for my Adler Barbour...
« Reply #5 on: November 20, 2014, 09:15:10 am »
Richard..good morning...

first question...yes...two complete independent AB units wired separately to the main buss with individual circuit breakers.
Yes...both ab units have the stainless steel box with the two small fuses, and the LED.
Yes....two separate TSTATS

After 24 hours of run time with the reduced sense tube connected to the top evaporator, I have lowered the internal evaporator temp by about 3 degrees, which is OK.  And, actually, I am happy with this.  This system has been installed for about 7 years now, without any problems, and I do not have any problems now.  Just thought I could get the freezer a little colder.  This is a 2.3 cuft area, and is full of meat.  We travel to the Bahamas for 6 months, and everything stays frozen.  Until ready to consume. 

Richard..I know, if it ain't broke, don't fix it and if it ain't broke...don't use it!  I just thought it would be nice if both units turn on and off at the same time.  I installed 2 units in the same box for redundance incase one or the other should fail, while I am out in the middle of nowhere, with a box full of meat, fish, and lobsters.

I built the box, with good quality urethane foam.  5 inches on the bottom, 4 inches on all sides, and 5 inches on the top.  Top loading, with an internal fiberglass vapor barrier.

One thing that I did notice was...the upper evaporator, with the reduced sense tube has taken control of the box.  Meaning, that it gets the freezer colder and the lower evaporator never gets a chance to cycle on, as coldness sinks..so to speak.

I was just thinking, if I could turn on both units, when the top evaporator turns on, the bottom evaporator would get used more, and the whole freezer would get colder.

Using a relay...would that go into the TSTAT wire?  One TSTAT turns on the other TSTAT..

Richard..thank you for your expert help and recommendations.


Richard

  • Administrator
  • Sr. Member
  • *****
  • Posts: 349
    • View Profile
Re: where do I find a "freezer" thermostat for my Adler Barbour...
« Reply #6 on: November 21, 2014, 07:14:59 pm »
Because both Adler Barbour units are powered separately and grounded separately  at main battery busses it is possible to start them at the same time without either unit’s controller sensing a micro second low voltage spike.

Because you now have control of box temperature through the top evaporator thermostat let us identify it as system #1 thermostat.

A simple addition of a $3 relay and a switch will permit system number 1  to operate both systems from #1 thermostat when needed. The switch will provide energy savings and redundancy if only one unit has trouble or is not required.

First you will need a small relay I recommend a standard plug in auto relay, these were priced at less than $5 but you need to shop around. The capacity of relay for this job is less than one amp but the small cube auto relays available are all rated at 30 to 40 amps and require no soldering.

On the system #1 stainless box there are plus and minus external fan terminals these will be used to control relay by closing it when compressor #1 starts. A switch will be installed in one of these wires When this switch is open both units will revert back to the original two independent system thermostat controls.
The two relay terminal wires that switch relay on second compressor carry 5 milliamps or less are to be connected to system #2 Danfoss control module terminals C and T along with the wires already there from system #2 thermostat.




denogail

  • Newbie
  • *
  • Posts: 11
    • View Profile
Re: where do I find a "freezer" thermostat for my Adler Barbour...
« Reply #7 on: November 22, 2014, 09:58:06 am »
Again..Richard, thank you for the information.  I do have the necessary relay and switch.  I understand what you are saying.  I will get to the back of the units and make the necessary changes. 

Dennis

Richard

  • Administrator
  • Sr. Member
  • *****
  • Posts: 349
    • View Profile
Re: where do I find a "freezer" thermostat for my Adler Barbour...
« Reply #8 on: November 22, 2014, 01:30:57 pm »

Make sure you connect relay correctly because the 12 volts from external fan terminals of system #1must not reach the thermostat circuit of system #2. 

I also want to point out that when both units are now controlled by #1 thermostat #2 compressor unit will run at minimum Rpm of 2000 because its speed resistor is located in thermostat #2 wiring one inch away from its thermostat. This low speed of #2 compressor when both units are running should be a performance advantage. If you want to know what speed each unit is set to run at when units are running without new relay powered there is a paper decal on each thermostat’s plastic cover, the last numbers can be used to identify speed. Adler Barbour has a predetermined speed resistor for each evaporator size sold this is why thermostat and its wring is part of evaporator package.

denogail

  • Newbie
  • *
  • Posts: 11
    • View Profile
Re: where do I find a "freezer" thermostat for my Adler Barbour...
« Reply #9 on: November 23, 2014, 06:55:09 am »
Thank you Richard...I do understand the idea of isolation...between the two units.  I have been monitoring the first modification...the shorting of the sense tube touching the insulator on the evaporator...What I did, was to make a"J" on the end, like the book calls for, but 1/2 the size.  Meaning, there is about 2 inches of sense tube involved instead of the 5 inches.  This has lowered the internal temp of the top evaporator by 3 degrees.  Yes, that is an improvement.  Keep in mind that I never really had a problem with keeping stuff frozen for months on end.  But, I just wanted to get the box a little colder.

I understand, also, about the speed resistor, and the #2 compressor running at 2000.  In the beginning, when I install these 3 different units, 2 in the freezer, and 1 for the refrig..seperate box...I connected blue LED's to each AUX fan terminal on the controller.  These LED's are on the dash of the boat, with labels, so I know when each unit turns on and off.  I have timed the on/off duty cycle, to make sure that none go over 50% ON TIME...as I have heard/read? the units are not designed for that.  Anyways, the refrig runs at about 25% duty cycle, and the top evaporator in the freezer runs at about 20%, when the box is down to temp, and I have not put anything new in to be frozen.  The bottom evaporator in the freezer, well it does turn on, sometimes, but the ON/OFF duty cycle of that evaporator is around 5%.

So, as soon as I get time to crawl outboard, where the compressors are located, and hang upside down, I will install the relay, that you have mentioned.

Thanks again..Denns