unexpected results in refrigeration system!

[doog]

Hopefully on the right page, posting here. I see great stuff on the always important subject of refrigeration.

I have a low draw, low power electric system that is very reliable and in trying to get the box cooler, I reduced the size by 50% which helped a ton, along with adding another inch of blue board insulation. And on a warm day when the icebox compartment was reading 18/20 on the coils I attempted to cool the condenser side which was 105 with a fan. And I dropped it to about 85/90 right away but the result was not getting a colder evaporator side, but much warmer! It immediately went to barely freezing.
So I thought, something is going on here akin to absorption refrigeration, and applied HEAT to the condenser and yep, the evaporator dropped to zero and got much colder right away.
So if the reefer scientists could comment on this perhaps they are well aware of why this result and if it indicates perhaps a low refrigerant level or some absorption type effect that occurs in the old freon compressor systems. I wonder if perhaps the oil that the compressor needs had settled out and the heat got it up into the coils and rejuvinated the works.
Thanks again everyone for the helpful comments and years of experience behind the good advice here.

[Bowdrie]

Very interesting.
You've not indicated if your system utilizes a cap-tube or a TXV, or what refrigerant you're using, or any pressure readings, (if able to be measured).
However, I've experienced those symptoms twice, both on systems with TXV control of the evaporators.
Once with a water-cooled system, once on my own air-cooled system.
Whether TXV or cap-tube, heat removal is dependent upon expansion of the refrigerant, basically turning from a high-pressure liquid to a low-pressure gas.
Is your system "home built"? Sometimes a cap tube is used that is either too large in diameter, or too short in its length, if so, the expansion ratio can be on the "back side of the curve" for the refrigerant used.
Just as an analogy, it is possible to get a system into an area that an aircraft pilot would refer to as the "coffin corner", go faster and you exceed the max allowable speed, go slower and you stall.
I'm sure that somebody will come along that perhaps has more experience with such symptoms, and a bit more info on the system would help.

[doog]

Thanks for the comments Bowdrie,
Its just an old swap meet electric cooler system with a little old style inverter built into the compressor unit and condenser cage, about 8 amp draw with a little cold plate and a double coil aluminum heat exchanger all permanently sealed. Its been running nearly 20 years off and on, after a long sit in storage. Freon refrigerant. No gages or access to the system without modifying it and adding a fill/drain valve.
All I know is that the application of heat very much boosted the cold-making ability. And now possibly it might help to put a cooling fan on the compressor side, perhaps what happened was that a filter got cleared of obstruction or oil was liquified and got where it was needed. Im almost able to get freezing out of the system now.