Fridge/freezer

[fixbear]

What configuration is the unit? Top or bottom freezer, one, two, or three door?

[coffeegeek]

Bottom freezer, two doors.

[olivero]

Not sure there is a valve that you could manually adjust for refrigerant flow, it’s normally a pretty calculated mechanism that’s sized and restricted for a specific flow in a specific size of unit.

As for compressors, if they have the right amount of cooling and aren’t “overcooled” then they will in theory last for many years. It’s not uncommon for them to last upwards of 10 years if installed correctly and treated properly.

[coffeegeek]

I figured so… A manual adjustment would be awesome though. It’s 12 years now, and the fridge have always been bad, freezer very good.

I think “upwards of 10 years” is horrible lifetime. We have a chest freezer from around 1955. It still runs cool and quiet. Probably poor efficiency and loaded with an environmentally bad medium, but it still runs. If 10 years lifetime is the new normal, means we should run through 7 freezers in the same time (probably more since the old one still runs).

[fixbear]

If it has a electronic temp control and is a bottom freezer it may have 2 evaporators. And if it has chill draws for meat and produce, It will also have dampers. Do some research for a service manual and parts breakdown.

Now the high temps in the cooler box are most likely a evaporator freeze up or fan problem. You will not gain anything from changing the method of control. They are built to be very balanced in operation for not so experienced users. It may also be a LG or Samsung. Does it have a control panel in the top munnion?

[coffeegeek]

It’s not electronic controlled, it has a regular thermostat. It has drawers for produce.

I’ll have to try to find the service manual.

I would think exchanging the thermostat with a Dixell and a NTC sensor, will force the temperature down until the Dixell is happy 🙂

[fixbear]

But it will also cause repeated freeze ups of the evaporator. BTW, that means you have a mechanical defrost timer. Usually under the front behind the kick plate. But some rare models have it inside the control console. They usually last 8 to 10 years before the timer motor starts to hang up trying to change over from cooling to defrost and back. GEM makes (or made, IDK) a replacement kit that has 8 timers and will cover most applications. Most domestic fridges are 6 or 8 hour cooling and 20 to 40 min defrost.

Don’t make assumptions, check the evap for ice and air flow. I have seen Styrofoam insulation not where it belongs partially blocking air flow to upper area and drawers. Remember they do stamp them together by the thousand per day.

[fixbear]

Just for your knowledge, in 1986 there was a across the field agreement from GE and others that they would build domestic appliances for a 10 year lifespan. They weren’t selling enough units. I still know of a Richmore 30 cu ft chest freezer that has run since 1950. Also my family still has 2 GE monitor tops in use. One two door my Mom bought new for my grandmother in 1928. Can’t beat ammonia (R717) as a refrigerant in a properly designed system..

Not a fan of throw away equipment or minimal design of today.

[fixbear]

If it never cooled right from the get go, You’ll want to take the freezer evaporator apart and verify that the fan blade is rotating the right direction and not mounted in reverse. Or the aluminized heat deflector for defrost isn’t blocking the air port to the top.

You should also check for recalls and lawsuits on your model. If it’s on the list, they’ll just give you a new one.

[coffeegeek]

Since it freezes down to almost -30’C, I would think the evaporator fan is correct. Just the ratio fridge/freezer is off.

[fixbear]

Not necessarily. The supply and return to the freezer compartment has to be clear and of proper pressure to flow air. Restriction on either or fan pressure will doom it from balancing. This includes fan motor RPM’s.

[coffeegeek]

I think I’ve seen defrost in the Dixell menu? I’m not sure how the defrost works.

[fixbear]

Yes, if you knew the K values, the capacity of both spaces, the condenser curve, the defrost efficiency, BTU input, Btu removal, The designed air flow and be willing to build a whole new wiring harness, thermistor mounts and location engineering. Believe it or not, domestic refrigerator have a lot more engineering in them than a walk in or reach in does. Mainly because they are 2 compartments or more with one compressor. And balance between them has been a engineering problem for century.

Dixel was designed just to cover all kinds of control problems. But remember you also have to have a sensor IN or attached to the evaporator coil at the right place.

[fixbear]

I have seen a field repair on a bottom freezer that had them place a tape baffle on the freezer air suction to restrict it and increase to cooling to the top.

[coffeegeek]

I’ve taken a look now (and I couldn’t resist modifying with the Dixell). There are three cables running up to the cooling compartments (brown, black and blue). The fridge thermostat is located at the top of the fridge and receives the brown and black. The power indicator and light bulb receives the blue and takes the black from the thermostat. There are no more cables running from the compressor (floor level) to the fridge or freezer compartments. So it seems there is only the one thermostat in the fridge controlling the compressor. Just to make sure, I disconnected all three cables in both ends and measured resistance between them all, all open circuit (to see that it wasn’t bridged to a secondary thermostat on it’s way up).

I can also see there is a thin tube (temperature sensor?) in the top of the freezer resting over the evaporator coils. This is probably leading to a mechanical valve for fridge/freezer distribution? I disconnected the thermostat in the fridge compartment (brown and black), and connected these to the Dixell relay output, with a NTC placed in the middle of the fridge (which I inserted through the condensed “water hole”). It cooled instantly (within 20 min?) to -15’C in the freezer (I placed a K-type thermocouple in there) while the fridge remained 22’C. When the freezer hit about -15’C, the fridge started cooling. So I assume it has some kind of mechanical valve, opening the cooling circuit to the fridge, when the freezer hits some minimum temperature? Fridge cools very slow though… After 1.5 hours, fridge is down to 3.6’C and freezer -22.5’C.

Hopefully the mechanical thermostat is actually switching at the same relative temperature I want (around 2-4’C) and the sensor is located somewhere it actually picks up the actual fridge compartment temperature, since the Dixell is set at 3’C with the sensor in the compartment (and is now acting as a replacement for the thermostat). Well, if it doesn’t it’s all a matter of offset temperature in the controller. I’m also a bit concerned the sensor is way too fast for the slow compressor, so the latency will make the system oscillate.

[fixbear]

You can program the dixel to have a cut in, cut out range. Most are already 4F.

I’ve never come across a mechanical hydraulic damper. The thin tube in the evaporator is probably a temp sensor for a thermostat. Or a defrost termination switch. Especially because it’s across the top of the evaporator. It will also control the cooling fan so that it will not run till the evaporator is freezing.

Did you find the defrost timer? It will normally have 4 wires, and stops the compressor and fans, turns on the heater. It will have a neutral for the timer motor, line, compressor, and defrost heater. Check the wiring diagram for how it does this with a little creative wiring.

I don’t know about your side of the pond, but here they have to have the wiring both in a pouch underneath and attached to the back.

Did you verify that the air is moving to the top and out each duct?