Adler Barbour Refrigeration - Cycle Time

[nknowland]

Is there a "standard" cycle time for an AB refrig? I just started noting the times on our refrig, and it's cycling on for 4 minutes about 10 minutes. Is that "normal"? Everything works fine ... just wondering how you know when your refrig is having problems? It is b/c it cannot hold temp? Or is it cycle time?

thanks.

[Richard Kollmann]

Is there a "standard" cycle time for an AB refrig? The answer is, NO as there are many factors that affect the number of cycle times per hour that change Adler Barbour's compressor cycling times such as:

Super and sub cooling of high pressure gas is either too much in cold weather or poor condenser cooling in warm weather.

Incorrect refrigerant charge.

Ambient temperature change.

Lack of insulation.

Moisture in insulation.

Thermostat setting.

If unit has a BD50 compressor its speed is set to run higher than necessary.


To assure yourself that this AB system is operating correctly check to see that thermostat is installed correctly per AB instructions. Thermostat’s temperature sense tube must not touch evaporator anywhere except where it is designed to be clamped. After unit has operated for at least one day with thermostat set at mid range there must be frost covering at least 90% of evaporator’s surface area and no frost on return line outside refrigerated area returning to compressor. Make sure condenser airflow is adequate and warm heated air is not allowed to pass through condenser a second time.

[onestepcsy37]

when my fridge was six cubic feet my adler barbour super cold machine seemed to run about half the time - maybe 15 minutes on, 15 minutes off.

i decided six cf was way too big for what i needed so i filled the bottom with one inch thick insulation board cut to fit, reducing the capacity to about three cubic feet. now the a-b runs about ten minutes on, twenty minutes off.

[senormechanico]

One more thing which will determine how often it cycles.
The amount and type of stuff you have in the fridge, especially in the freezer.
More frozen stuff, ice etc, the longer the cycle time, both on and off.

[Chef Mike]

Any thoughts on why the refer does not cycle?? My Alder Barbour spill over system runs continuously. I have tried replacing the thermostat with no luck.

[Richard Kollmann]

There are many possible answers as to why AB compressor runs continuously:

Faulty thermostat or its wiring. If it is a thermostat related problem box will keep getting colder till every thing inside is frozen.

Poor condenser cooling. On some AB units in order to clean dust and hair from condenser coil once a year fan needs to be removed.

Incorrect refrigerant charge. Not enough refrigerant will prevent complete surface area of evaporator from frosting over. Too much refrigerant will frost over return line outside refrigerator towards compressor.

Warm climate and box’s heat load too large for refrigeration unit’s small capacity. Or possible moisture in insulation or not enough insulation.

If this is an AB CU100 or CU200 which means it has a variable speed compressor its speed is too slow.

[sailorboy1]

My unit seems to run all the time. It is a spill over system and the performance is good and it froze the small amount of stuff in the freezer and cooled down the frig side that was loaded with drinks to around 35 degrees in 12 hours.

The evaporator is all covered with frost and I cleaned the condenser the other day. If I turn down the thermostat it cycles off etc so that sees OK.

Daily power use seems OK and I think I would like it to run less, but faster, even if that takes a little more power per day. (I get tired of hearing it run at night).

Is there an easy way to turn the compressor speed up?

[Frigoboat Info]

Compressor run times alone are no indication of a systems efficiency, as we'd need to know what speed the compressor is running at. Adler Barbour use a medium speed that is determined by a resistor buried in the thermostat housing, but once this is removed from the circuit you can use a manual or automatic speed controller like these shown here: Speed Controllers for Danfoss BD 35/50 Compressors
Unfortunately, if your air cooled system is noisy, long run times might create a nuisance factor, even though you wouuld be getting more efficiency.

[sailorboy1]

Originally Posted by Frigoboat Info

Unfortunately, if your air cooled system is noisy, long run times might create a nuisance factor, even though you wouuld be getting more efficiency.

That is the issue to me. But now that I think about it I'm not really sure that the system performance really is good . I have a thermometer on the middle shelf of the freezer and I don't think it ever reads lower than 20 degrees (which is enough for things on the lower shelf to be rock). I don't think the thermostat matters much, but haven't ever spent weeks on the boat at once to adjust it to find out.

Am I correct that there is a way to read the LEDs on the unit to find out what speed it is running at?

[Frigoboat Info]

What type of evaporator do you have, Don? Is the thermostat the standard one supplied with a A/B system?

[sailorboy1]

Originally Posted by Frigoboat Info

What type of evaporator do you have, Don? Is the thermostat the standard one supplied with a A/B system?

It is a thin metal/aluminum 'C" shaped unit. Probably is around 24"W x 24"H on each side (the freezer is prettty big). Far as I know it is a stock thermostat that is white with the rotary knob and 1>7 setting and the sensing bulb mounted to the corner of the evaporator.

[Frigoboat Info]

OK. So it's good that you have a "flat" type evaporator and not the "bin" type normally supplied by A/B. For freezer applications you should have a dedicated freezer thermostat, with a lower range than the standard fridge item.
It sounds like you need to investigate the resistor in the thermostat, and if it is not set to run the compressor at full speed, then it should be removed or by-passed and a speed controller of some sort installed. Contrary to logical thinking, removing the resistor will make the compressor run at the lowest speed, and you need to add resistance to speed the compressor up.
The LED on your A/B unit is a fault diagnostic diode and does not show compressor speed. The Frigoboat Merlin has a speed indicator LED.

[tamicatana]

How clean are the fan and the coils? I find that I have to brush dust off my AB with some frequency

[skipmac]

Looks like this is the current thread for refer problems I guess I'll jump in with my latest question. I'm sure Don won't mind and if he does, well he's in MA and I'm in FL.

I have fixed the problem I had with the controller continuously cycling on and off. Even though I could detect no voltage drop, even with a recording volt meter that must have been the problem since a new wire and with new crimp connectors seemed to solve the problem.

Now the problem I have is the system is working too well. I have the bin evaporator installed horizontally on the top of the box with a spill over fan/thermostat installed in the front door of the bin. The bin has <1" clearance to the sides of the box but about 18" front and back.

I set the Coastal thermostat at 12F with the sensor inside the bin and the spillover at 40F but the fan never kicks in and the temp in the bottom of the box measures 28-30F. Currently I have very little in the box since I'm on the hard and just running it for testing.

I'm wondering if I should put some insulation or a just a sheet of some material under the bin to hold more cold in the bin and keep the box warmer. Would this reduce the efficiency of the evaporator overall?

Thanks
Skip

[Frigoboat Info]

Good to hear you solved the power problem, Skip.
What you are attempting is not a standard spillover installation. If you have a single box, and a horizontal bin evaporator with a lid mounted high in the box, then that is all you need. Inside the evaporator will be the freezer and the rest of the box will be a refrigerator. Installing a spillover fan in the door of the evaporator is both unnecessary and self-defeating, as it will allow cold air to escape from the evaporator, through the blades of the fan, even when it is not turning I suggest you de-power this device and put some masking tape over the fan opening to stop the cold air escaping. The thermostat probe should be mounted in the box, at about mid-height, and on a wall not under the evaporator, then set to 38-40F as a fridge thermostat.
I think you'll find that if you make the above adjustments, you will have much better results. Using a Merlin compressor speed controller on this type of installation not only results in less power consumption, but ensures super-cold temperatures in the freezer.