Sub-Zero 550 Icing Badly in Freezer, Right Side

[borhani]

Hi, Sub-Zero Model 550, S/N M1133203, manufactured Oct. 1994. Been the owner of it for 10 years.

I've been struggling with severe freezer icing,on and off, for 2 years. Icing gets worse, then better for no apparent reason, and now (much) worse again.

Condenser is frosty; right side (only) has mini-icicles "trailing" down the wall; pooling as ice on the right drawer track; and a large block of ice along right bottom, from front to back. Drawer seal seems to be leaking very slightly at lower-right corner.

I have shut off and fully defrosted the entire freezer more times than I can count. A year ago, such a defrost would then keep it essentially ice free for a few months or more. Now, it's down to only a week before so much ice accumulated that I can barely open the freezer drawer. The drain tube is clear; drain pan had ~¼ inch of standing water at last manual defrost.

I looked at this thread, which seems related: https://appliantology.org/topic/58925-subzero-550-question-about-freezer-icing-over. I don't have any ice/frost at all on the left or middle of the freezer compartment.

Questions:

1. What's broken? Defrost timer, defrost thermostat, heater element(s), and/or drawer seal? Or something else?
2. Start with the "turn the timer" approach described in the linked post?
3. Where is the defrost thermostat located?
4. The defrost heater (I assume this is what it is---looks like a U-shaped electric oven heating element) is horizontally offset by ~½ inch on the condenser fins: it's in good contact with the fins, just looks like it got slid left/right from where it was originally mated onto the fins. Tried to nudge it back, but it doesn't move. Does this matter?

Many thanks!

 

[borhani]

Oops, I meant evaporator, not condenser!

[borhani]

Update: May be the timer...

[borhani]

2nd Update: On second thought, I'm not sure it's the timer. When I manually turn the timer, I hear the "CLICK". Did this twice w/ freezer drawer shut (about 15 min total). The area around the evaporator was not at all warm. At that point, I took out the drawer, turned timer again, and waited. Some defrosting, but that happens whenever I take out the drawer.

The heating element never felt warm to the touch. Should it?

Big ice plug in drain. Even after having it open, and timer 5 times in a row, still plugged. Unplugged with hot water.

So, maybe it's the thermostat?

How warm should the element get? Resistance of the element? A few ohms (or kilo-ohms)?

Thanks!

 

[vee8power]

I would take care of the obvious problem first; fix the drawer sealing issue. See if that keeps the drain from repeatedly freezing; make sure the drain is totally clear. 

The defrost heater comes on during the defrost phase of the timer but only if the freezer is cold. The defrost thermostat will be open if you just manually defrosted everything. A defrost issue by itself usually shows up as an evaporator completely clogged with frost(as opposed to ice).

[borhani]

vee8power, thanks, will do!

[borhani]

Need your help again. I decided to waste a bit of $ rather than do this piecemeal. I replaced the freezer door gasket, the defrost timer, and the defrost terminator (thermostat). All parts from subzero. I even took the opportunity to braze together some broken connections on the freezer upper wire rack!

For the first 4 days, no ice accumulation. Now, 5th day, ice in the same place, dribbling down from where the drain pain under the evaporator goes into the tube that leads out of the freezer cabinet.

Is it safe to assume, at this point, that it is defrosting, but the issue is that when it does so the water drain still has an ice plug in it, so the water can't drain, and instead dribbles down and then re-freezes?

The drain tube has the very lame looking aluminum "finger" that sticks into the tube; at the other end, it is wrapped around the heater coil. I even put some heatsink compound at that connection, to help ensure the finger would warm up...

Suggestions? I'd like to throw this whole freezer out the window at this point!

Separately, I have a light bulb out in the refrigerator compartment, behind the control dial. I can't find how you get to it, i.e. what needs to come off first, second...to access the bulb.  Has anyone done this?

Thanks!

[northeastappliance]

Call sub zero parts department. Give them your serial # and ask for the defrost heater kit. It looks like a shoe lace that wires in to the defrost heater. It keeps the drain tube warm so that the water does not freeze. 

I've installed them in 550 freezer defrost drains and never had any issues after that. 

[borhani]

Thanks, will do!

[borhani]

Got the drain tube heater. Installation was a pain (the string they give you to "pull" the shoelace into the drain tube is a bit silly). I carefully squeezed the end of the heater shoelace (its actually a metal-braided loop), and managed to fit it into the drain tube, and then inched it into place. Dishwashing soap helped, as the instructions suggested. It's been two days...fingers crossed that I'll never have to give this freezer a second thought again!

[Coley]

Have a customer with this exact problem. How did the fix go?

[borhani]

Coley,

The fix went great. As I mentioned, the hardest part was just getting the heater stuck down into the drain tube. So, I've gone from Feb. 18 to Aug. 26, and NO ICING! 

In summary, I would recommend that you go for it. By the way, I did have a hard time w/ Sub Zero getting the correct part number. It is: PN 4202160,  "550 FREEZER DRAIN HEATER"

Good luck!

David

[borhani]

Update: Freezer iced up despite having the drain tube heater. This happened about a month ago. Defrosted everything, now back to normal. Unclear why it was good for several months, then went bad, and now has been good again. 

David

 

[AccApp]

These drains are also subject to normal non-freeze related clogging. I'd remove the new heater temporarily, blast some steam down that hole until clear, then pour some 1:10 bleach/hot water down there. Reinstall the heater and it should be fine.

[borhani]

Thanks, AccApp, will give that a try next time it acts up!

David

[AccApp]

You don’t need to use the genuine sub-zero fishing line to pull the heater back down. Any generic fishing line should do if it’s flexible enough to be tied in a knot.

[16345Ed]

Be gentle with those drain tubes they can tear or rip so to speak. 

I can't imagine what it would take to replace one. 

[certified tech group 51]

if you are still having the drain tube freezing up, I would look into installing a  " Floor defrost Package"   P/N 4202530...The fresh food floor/ freezer ceiling insulation is saturated, freezing temp in the freezer is causing the floor of the fresh food section to get down to freezing temps....

[borhani]

CTG 51, insulation is saturated with...water? I'm probably missing something, but why should any of these add-on defrost packages be necessary?

[Chief Petty Officer Crowe]

@certified tech group 51 Is right on. This is a known issue on these older fridges. Most refrigerators are subject to some amount of moisture infiltration and condensation in the cabinet urethane foam. The defrost kit is an inexpensive bandaid kit to work around the problem and restore normal operation. 

[borhani]

@certified tech group 51, @Chief Petty Officer Crowe, thanks.

I had to defrost the freezer again. Small (½ inch) plug of ice at the *top* of the drain tube. The ice had formed *around* the defrost wires. I checked the wire connections, and they seem fine (firmly hooked together). I think the main defrost heater is working (timer ok, heater coil circuitry ok) because there were little ice droplets at the *bottom* of the fins, like it had partially defrosted before everything got stuck.

If the drain tube heater is working, it shouldn't have this ice plug, right? Check continuity on the drain tube heater? If so, any idea on what resistance a working heater has?

Thanks

[AccApp]

18 hours ago, Chief Petty Officer Crowe said:

 The defrost kit is an inexpensive bandaid kit to work around the problem and restore normal operation. 

Inexpensive? Hah! May not cost a lot of money at first but it will increase operating expenses.

17 hours ago, borhani said:

If the drain tube heater is working, it shouldn't have this ice plug, right? Check continuity on the drain tube heater? If so, any idea on what resistance a working heater has?

Thanks

Maybe the heater is too far down the tube? As I recall, these have about 50 ohm resistance but don't quote me. You can always call Sub-Zero and get real tech support from them, 800-222-7820.

[Chief Petty Officer Crowe]

1 hour ago, AccApp said:

Inexpensive? Hah! May not cost a lot of money at first but it will increase operating expenses.

Yeah, that additional 3 watt heat load factored into the monthly power bill amortized over years. Why I’ll bet in just 397.4 years he’ll have spent enough money on additional electricity to have justified purchasing a a whole $15,000 Sub-Zero. 

Yeah, great point. Guy might as well cut his losses now, shit-can the fridge now and get a new one.  

[Moostafa]

Hello, Chief Crowe, my amortized friend. May I offer that the additional operating costs are relative to someone’s situation and our inexpensive friend, AccApp, may have a valid point. Please allow me to explain. 

I offer my own situation here in Afghanistan as an example. I generate my own electricity using a proprietary camel dung and lime juice battery technology that I invented. I power my entire tent complex using this technology. The additional 3 watt heat load that you posit would require the addition of two camels to my herd. Each camel must be fed and sheltered (from occasional sand storms) thereby adding significant cost to each kw-hour of electricity produced.

So, you see, our friend AccApp has a valid point since the additional operating cost is, eh, how do you Ameedican pig-dogs say— relative to each particular situation. 

I trust my comments are not seen as impertinent and received in the spirit of good will in which they are offered. 

Allahu Akbar!

[Chief Petty Officer Crowe]

Well, evidently someone has been smoking the fruits of a record-breaking poppy harvest this year. Sadly, I have to crash @Moostafa's opium party with a reality check. 

49 minutes ago, Moostafa said:

I generate my own electricity using a proprietary camel dung and lime juice battery technology that I invented.

You must have invented this in an opium-powered alternate universe because, in this universe, no combination of camel dung (or any other dung) with lime juice produces electricity. The chemistry in our reality just doesn't work that way. So, if you'll pardon the expression, I call bullshit on your camel dung battery.