Newbie Question (and also, check out my refrigeration hack)

**dustball** · 24-07-2009, 04:08 AM

New to refrigeration engineering .. though I am an engineer in my professional work.

I purchased an old Frigidaire CF-083 chest freezer, and wired a Love Controls temperature controller into it. It looks downright beautiful, with the display flush mounted.

Anyway, the wiring is plain and simple. Power comes in, wired in serial with the thermostat. Doesn't get much easier then that, huh? I replaced the thermostat with my high-tech controller, and confirmed the relay activates at the correct time: when the temperature is above SP, the compressor comes to life.

Question:

After initial testing (in which the temperature DID go down to SP for half a day), I put the freezer in place outside on my patio where I intend to keep it.

It no longer seems to cool.

The compressor runs, but doesn't seem to bring the temp down. Sometimes it sounds like liquid is trickling ... has ***** pressure dropped too low? Did I kill the compressor by putting it in direct sunlight on a hot (90F) patio?

SP is 50F.

Cheers, and hope you like my first engineering attempt

-B

**Gary** · 24-07-2009, 07:04 AM

Where did you mount the temperature sensor for your new control?

**dustball** · 24-07-2009, 07:43 AM

The sensor itself is halfway up the back side.

Opening the fridge ... its just not cold.

**Gary** · 24-07-2009, 07:52 AM

Originally Posted by dustball

The sensor itself is halfway up the back side.

Opening the fridge ... its just not cold.

Did you mount the sensor in the same place as the thermostat sensor? Did you drill holes through the cabinet? Did you nick any copper tubes?

**dustball** · 24-07-2009, 05:06 PM

The thermostat sensor goes into the cabinet, I don't know where it ends up. I did not drill any holes.

Should sensor placement really matter if the fridge doesn't come anywhere close to SP? It only seems to cool a few degrees right now, and this is verified by using a second thermometer in various places.

**Gary** · 24-07-2009, 05:38 PM

If you have a wiring diagram on the unit, take a picture of it.

**Brian_UK** · 24-07-2009, 10:50 PM

Putting the unit in 90 deg heat probably hasn't helped it.

**crit71** · 25-07-2009, 12:16 AM

Sounds short of gas to me tbh....although the knocking trickling sound is usually a symptom of overcharging. Sorry to confuse you further.

famman1 · 25-07-2009, 03:24 AM

1. When it runs, feel the discharge pipe and the suction pipe at the same time and you should have a big difference in temperature mate, if the discharge pipe is not really hot and the suction pipe is not really cold, it's not pumping (valves are smashed)and you should replace the compressor just to get some practise at it.(not cost effective but good practise)
2. If the discharge is hot and the suction is only midly cold, you might have a leak.
3. If you have placed it somewhere in the extreme heat or have obstructed the airflow over the condenser coil or the condenser coil is dirty, give it a clean (not with degreaser) or move it out from the wall a touch to give it more airflow as it may be overheating the compressor.

famman1 · 25-07-2009, 03:28 AM

It sounds like you have just put it somewhere too hot or not enogh air flow to cool the compressor since it worked before you moved it into place...

**dustball** · 25-07-2009, 09:18 PM

Wiring diagram as requested. It doesn't have any of the optional components as indicated by the dotted lines. I basically just wired the new controller in replace of the old one (black & yellow wires).

I will feel the pipes and report back.

Note I have moved the unit back inside where it is 75F, and even had a fan blowing on the back coils, but no luck.

**dustball** · 25-07-2009, 10:03 PM

Also, I don't think its overcharged because the unit is so old and hasn't been refilled. I do hear what sounds like liquid trickling throughout, especially if I put my ear up against the cabinet.

**Gary** · 25-07-2009, 11:01 PM

When you moved it, did you lay it on its side?

**dustball** · 25-07-2009, 11:15 PM

Yes I laid it on its side to wire the controller in.

I didn't wait any time before plugging it in, which after a quick google search tells me this was quite a bad idea, as you need to let the gas settle.

(I've since let it sit for 24hours, but I'm afraid its too late.)

What exactly kind of damage happened? Any rescue?

**Gary** · 25-07-2009, 11:33 PM

What happens is that the oil drains out of the compressor and must work its way through the system in order to return to the compressor.

If you run it for a few minutes at a time, then leave it off for a while, this may help the oil return.

The compressor may or may not be damaged.

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