i need help understanding what is wrong with my refrigerator

[nucleus]

the simple symptom is inadequate cooling.

the details are:

1. the refrigerator is a 12 year old kenmore top freezer model with R134a system
2. just installed a new compressor and drier, my thanks to HVAC tech for brazing in
3. i triple evacuated and then charged with 4.0 ounces R134a, which was amount on sticker inside refrigerator
4. process stub has service port and new drier has service port, not piercing valves
5. ambient air temp over clean condenser coils 87 F
6. lo pres at process stub 3 psig
7. hi pres at drier inlet 185 psig
8. evap inlet temp is 30 F
9. evap outlet temp is 67 F
10. compressor outlet feels hot, drier feels hot, compressor suction feels warm
11. with evap cover off, only two of ten evap loops are frosting
12. condenser fan and evap fan are running
13. defrost timer and defrost heater are off, during the above readings
14. no problem with door seals

do i have a plugged line somewhere?

[Stormin Mormon]

At this point, I'm thinking either dirty condensor, or maybe needs another ounce of non-freon.

[Zyp]

Fairly simple:

You installed a new filter drier. Is it the same as the one you pulled out? The "Factory" charge includes "Factory components." If your replacement filter drier is 'larger' you'll need to compensate by adding a few more ounces. On the original package for your replacement drier there may have been a chart for how much liquid refrigerant the drier holds. You may need to add more refrigerant.

[nucleus]

[Stormin Mormon]

That sure would explain the ref behaving like it's under charged. After all, the nameplate said only 4 ounces. Not a lot of room to work with, if it's high or low.

[Stormin Mormon]

High pressure depends on the heat load, and also the room temp. 185 is on the high end of the normal range.

Give it another ounce of freon, and let us know what happens.

[nucleus]

thanks CY and Zyp for being persistent about undercharging.

what i learned:

1. not to rely solely on hi & lo pressure readings. while the hi & lo pressures looked acceptable, i should have paid more attention to evap inlet & outlet temps.

1. not to rely on the sticker in the refrigerator which stated 4.000 ounces of R134a. summary, the total charge took 275 grams (nearly 9.7 ounces) of R134a.

IT'S WORKING PROPERLY NOW!!!

[Zyp]

Quite frankly;

it depends if you have a high load or hot pull down on the box. As a general guide line, you don't want the condenser saturation any higher than

30 deg over ambient. When it's at design, [meaning the fixture temperature is cold at setting,] it shouldn't be much higher than 15 - 20 deg.

[Zyp]

Although you believe the liquid drier is that same, it may have different internal space than the OEM. No matter how you cut it, there's a required amount of liquid still needed from the metering device to the condenser. The liquid drier is part of that circuit.

[Stormin Mormon]

I never, for a second, doubted you. Very well done.

[.p.jm.]

'Liquid drier' is such a wonderful term ... :-)

[The Daring Dufas]

In the factory, the charge is fine tuned. The initial charge may be installed but the tech will tweak it. Heck, a repair should use the factory spec as a starting point. Darn finicky little refrigeration units. I like the big ones with a sight glass, receiver tank and a TXV on the evaporator. *snicker*

TDD

[Stormin Mormon]

In many regards, the bigger ones are actually easier to service.

[hvacmam]

The refrigerator is BROKEN.

[.p.jm.]

Ah !

[Stormin Mormon]

You tuned in late. He fixed it.