External controller helping reduce compressor cycling?

Hello,
Would purchasing an external temp controller like a Johnson controls or STC100 reduce the cycling frequency of my kegerator?

My fridge is a very old 1940s/1950s fridge so I'd like to be gentle on the compressor. Is there any advantage to using an external controller with the probe in a gallon of water vs using the standard fridge controller?

The fridge tracks pretty regularly around 36-38 degrees but seems to cycle about once every 8-10 minutes. My understanding is that its not the running of the compressor but the startup of the compressor thats stressful to it.

Since right now the temp probe of the fridge is in the air, just outside the ice box portion of the fridge, I wondered if it would see less temp swings and start/stop less frequently if I used a controller.

Any thoughts?

My uneducated thoughts are that your old fridge is very likely going to outlast a newer fridge anyway. They were built tough back then.

The fridge will cycle as much as it needs to to satisfy the thermostat, whether it's an external device, or the built-in device. What causes cycle rate is the offset setting. you could make it cycle less often, but for a longer time by setting a wider offset. In this case an external device would be useful since setting the built-in offset might be more difficult if at all possible.

I think the real reason to use an "Anti Start Device" is when you program the fridge to operate outside of it's intended temp range, or for when you may have programmed incorrectly.

A fridge is designed to be cooled from room temp and to hold that temp. Usually it's very close to freezing.

My opinion is that 8-10 minutes won't overheat the compressor. I think my ASD setting is like 3 minutes.

a gallon of water will have less temperature fluctuation than air. Fridge cycling can be contributed to air leaks, bad insulation, bad placement of the probe, etc. Most compressors need a minimum of 2 minutes continuous run time in order to saturate bearings, warm surfaces and equalize pressures.

and homercidal is right. if the compressor has a differential switch which most do, then that will attribute to compressor cycling as well.. I mean if the thermostat temp setting is 33 degrees and the fridge didnt have a differential switch, then it would run ridiculously on off on off on off all the time just to keep it at 33 degrees. some thermostats do not have an adjustment for the differential and that could be a problem.

External controllers such as the stc-1000 also have a compressor delay setting that you can set manually, so if you choose to only have your compressor come on 20 minutes after it last shut off, you can set it that way.

Auber 2342 PIDs are programmed for both cycle time/delay and differential (hysteresis, IIRC) in the process of setting them up.

Someone on here had an example of putting the temperature probe in an old White Labs yeast tube filled with water, which as I recall was done for the very purpose you describe, limiting the cycling of their fridge.

Cycling every 8-10 min is too frequent IMO. You need to either have some thermal mass in the fridge or secure the probe to something with some thermal mass in order to help reduce temp swings and cycling. Or better yet do both.

Adding a temp controller can help for a few reasons. One, you can set the differential to at least a few degrees instead of being locked into whatever the fridge thermostat is. Two, the temp probe being on the end of a flexible cord makes it easier too secure it to something with some thermal mass. And three, most temp controllers can be programmed with a compressor delay. FWIW the max compressor delay setting on the STC-1000 is 10 min.

You can reduce cycling and wear without an external temp controller, but a controller will make it easier.

Concern for your 50+ year old compressor life at this point is like telling gramps who's been rolling his own most of his life that he'd better switch to filtered cigs.....

Even without an external controller, you'll cycle less often if you can add some mass inside. Just for example, if the fridge can hold three corny kegs but you only have one filled with beer, fill two others with water. The cycle time will be longer.

The suggestions on thermal mass are sound ones. Aside from this and back to your question: Johnson A419's had ASd - anti-short cycle delay. This is to mitigate exactly what you're worried about.

Thanks everyone!

The fridge seems to cycle a bit less now that it has about 15 gallons of beer inside

I did purchase a controller but havent hooked it up just yet. Part of me has a "dont fix whats not broken" opinion on this...if its been running strong for 50 years who am I to say its running too often?

I may do a formal test, get the controller set up and literally sit and count the on/off cycles for an hour with and without the controller.