I have a 12 cubic foot frost free fridge (Camco Model CRT1200VLT-1)
whose freezer isn't cold enough to keep meat frozen. This is one of
those GE apartment size fridges where you have to take out the freezer
floor to get to the evaporator, evaporator fan, defrost heater and
I can feel a draft in the freezer compartment, so I know the evaporator
fan is running. On this fridge the defrost thermostat diverts power
from the cold control to the defrost heater, so if the evaporator fan is
running, then the cold control is calling for cold, the evaporator fan
and compressor are getting power and therefore the fridge can't be stuck
in defrost mode. The compressor sounds like it's running when I use a
mechanic's stethoscope on it and the line between the compressor and the
condesnor coil behind the fridge is hot to the touch. Still the freezer
compartment isn't getting cold enough to freeze water or keep meat
I replaced the cold control, but that didn't do any good.
Until now, this fridge would make a loud knocking sound when the
compressor stopped, presumably due to a broken suspension spring inside
the compressor housing. Now, the compressor and evaporator fan seem to
run continuously 24/7 except for defrost cycles.
I'm coming to the conclusion that the refrigerant must have leaked out
of the sealed system on this fridge, and I need to buy a new fridge.
Is there anything I might be missing? Should I get an appliance repair
tech in to measure the pressure drop across the compressor to see if
that really is the problem, or have I covered all the bases already and
proving that it's a lack of refrigerant is just a waste of money?
Is the condensor behind the fridge? Is there a bunch
of horizontal back and forth tube, and wires that go
up and down?
If this is the case, the top 1/3 or 1/2 of this
assembly should be hot when the compressor is running.
If not, then very likely low freon. Please write back
and ask questions if you wish.
This fridge is equipped with a test plug.
According to the fridge's wiring diagram, measuring the resistance
between the orange wire of the test plug and the blue wire going to the
defrost timer will measure the resistance across the defrost heater. I
did that and measured 38.7 ohms. The factory spec is between 34.6 and
37.5, so it's a little out of range, but at least I know that the
defrost heater is in one piece.
According to the fridge's wiring diagram, measuring for continuity
between the orange wire of the test plug and the brown wire going to the
defrost timer will determine whether the defrost thermostat is making
the circuit to the defrost heater or breaking the circuit to the defrost
heater. I did that and got no continuity through the defrost
thermostat. So, the defrost thermostat is breaking the continuity to
the defrost heater.
That means that the defrost heater is good, but the defrost thermostat
isn't allowing any current through that heater, so I still could have a
block of ice around the evaporator coil.
In this case, a good assessment would be to unplug the fridge for a few
days to allow that ice to melt, and then fire up the fridge again. If
it freezes water initially, but then the freezer compartment warms up,
then I've got good evidence to believe the defrost thermostat is on the
fritz and preventing the defrost heater from working.
Thanks for everyone's input.
On Monday, July 14, 2014 7:16:19 PM UTC-4, nestork wrote:
Based on what you describe, it sounds to me all you're seeing is that
the defrost timer isn't at the point in time when it closes the switch
to turn the heat on. Which is what you'd expect to see, because it
only occurs a very small percentage of the time.
Well, it wasn't as cold as it should be, but manually defrosting the
evaporator coils and putting the fridge back into operation with clean
evaporator coils will at least tell me whether excessive ice
accumulation on the evaporator coils was the problem before.
No, not at all. In this fridge, the evaporator coil is located UNDER
the freezer floor. To remove that freezer floor, I have to remove both
the freezer compartment door and the fridge fresh food compartment
I will do that with the fridge running so as to preserve the frost
pattern on the evaporator coil.
I defrosted the fridge manually by unplugging it, propping the fridge
and freezer doors open, directing the melt water tube into a large
shallow pan on the floor behind the fridge and letting any frost on the
I collected about a quart of water, which to me means that the
evaporator was pretty iced up.
Once I was convinced that the evaporator coils were fully defrosted, I
put a plastic cup of water (covered by a jar lid) in the freezer
compartment and plugged the fridge back in. This test will determine
whether the fridge works properly when the evaporator coils ARE NOT
frosted up. If that water still doesn't freeze, then I'll look at the
frost pattern on the evaporator to see if it indicates a low refrigerant
charge. If the water does freeze, then I'm convinced the problem is
excessive frost accumulation on the evaporator coils, and I'm gonna
blame the DTS for that cuz the defrost heater shows continuity.
If replacing the defrost termination switch still doesn't solve the
problem, and the evaporator is frosted up along it's full length so it's
not a weak refrigerant charge, then I'm willing to call in an appliance
service tech to figure out what's wrong. I figure that if I go this far
and still can't solve the problem, then I'm prepared to pay for a
service call. For 99% of appliance problems, going as far as I have
will have determined the cause of the problem and the solution. I'm
willing to pay for that remaining 1 percent that I can't solve myself.
On this fridge, I have to remove the fridge and freezer compartment
doors to remove the freezer compartment floor. The evaporator is under
the freezer compartment floor. I have to bend the hard plastic freezer
floor to get it out of the freezer compartment. So, I'll let the fridge
fully defrost a second time so that the plastic I'm bending won't break.
Then I'll remove the freezer floor and plug the fridge back in to see
how the frost forms on the evaporator.
Well, after manually defrosting the fridge by unplugging it and leaving
it to warm up for a few days, I plugged the fridge in and left a plastic
cup of water in the freezer compartment overnight. Normally, that's
long enough to freeze the water into a solid block of ice.
But, the water didn't freeze.
And, apart from defrosting itself once every 20 hours or so, the
compressor and evaporator fan were running continuously overnight so far
as I can tell.
My next step is to take the freezer floor out of the fridge so I can see
the evaporator coils and how frost accumulates on them. At this point
I'm expecting to see proof of a low freon charge, and am thinking I'm
going to be buying a new fridge shortly.
I'll leave the fridge running with the water in a plastic glass in the
freezer for another day or two just to be certain that it's not gonna
freeze. Then I'll take the freezer floor out and see what's happening
at the evaporator coil.
On Wednesday, July 16, 2014 11:24:21 AM UTC-4, nestork wrote:
Why bother? If the compressor is running constantly, the fan in the
freezer is working, and it's been defrosted so it's not blocked by
ice, why do you need to see the coils? It's obviously a major failure
and it's not cooling.
What good would it be if it finally froze after two days? If the freezer
can't freeze over night, it's screwed.
Then I'll take the freezer floor out and see what's happening
Here in Canada, refrigerants are treated like toxic waste. You have to
have a license to work on AC and refrigeration systems in order to buy
refrigerants, and even then you have to meticulously document what
happened to the refrigerants you removed from equipment. You can't just
buy a piercing valve and "fill er up" like you could in the 1980's. If
I have a refrigerant leak, the service tech would have to evacuate the
remaining refrigerant in the fridge, find the leak and fix it,
re-evacuate the refrigeration lines in the fridge, and then add new
refrigerant. The cost for labour is roughly $300 to $400, and any parts
(like a new compressor) would be on top of that. It makes more economic
sense to buy a new fridge.
You're wondering why I want to bother seeing how the frost builds up on
the evaporator, and why I just don't chuck the fridge?
It's because I'm old enough to have been wrong in my assumptions more
than once, and I don't want to be wrong on this fridge cuz a new fridge
will cost me about $400. If I can see that the frost isn't forming
uniformly over the whole evaporator coil, then I know it's a weak
refrigerant charge, and I have no hesitation to salvage old parts from
the fridge and phone a metal salvage company to pick up that fridge.
However, I don't feel comfortable throwing the fridge away unless and
until I see how the frost accumulates on the evaporator coil.
CY: The US has the same regulations. Or some what
similar. When I got my EPA card, we were told that
if the system has less than 50 pounds of refrigerant,
it's legal to keep topping it off. Might be expensive
and impractical, but it's legal. For household refrig,
I don't have any moral problem with adding a couple
ounces. I can imagine that many techs would want to go
the recovery and leak check route.
CY: You can also check for heat on the condenser
coils, that's a good indication of charge.
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