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KBUDT4860A/02 Iced top of coil. Freezer not freezing Thermador


Premium Member
Nov 3, 2018
Model Number
Thermador side by side.
Noticed recently that it wasn't freezing and also fridge wasn't as cool as it should be.
Took panel off and, as can be seen in pic. The top part of the coils was heavily iced.
I melted it with hairdryer, reset it, started it again.

After three hours it looks like the top part is icing up again and the rest of the coils not getting frost.
Opinions appreciated.

Frozen Top Coil.jpg

[Update: I just saw a post by Jake that mentions this could be a Sealed System problem and is expensive to fix.]

(On another note, can anyone tell me what is the purpose of this small box at the side of the freezer compartment?)
White Box.jpg
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Yes, unfortunately that is a sealed system problem. The box is most likely the cover over the freezer thermistor.
Sealed System.jpg
Thanks Rick.
So there's nothing else worth checking?

I just wanted to verify so that I can advise technician over the phone.
They have to come quite a distance and I need to check that they have experience with this beforehand.
I'll bite the bullet..
It looks like a refrigerant leak or a restricted filter/drier. Worst case is a inefficient compressor. Either way the repair is going to involve opening the system. Sealed system repairs are expensive and will often exceed the machines value. The service tech is going to add a service valve to the system and connect his gauges. He should be able to tell by the gauges if it's a leak, restriction or compressor and then give you a quote for the repair. If you decide not to go with a system repair, you'll probably still need to pay for his service call.
OK in that case I'm going to give you some more information. Most of the problems with sealed system repairs is inexperience. Sealed system repairs are not difficult but need to be done right. In the 80's and 90's sealed system repairs were almost as common as replacing a thermostat. Once the government decided to phase out R12 and mandate service techs be certified to work with refrigerants, sealed system repairs dropped off considerably. There's a lot of service techs with years of experience repairing appliances but 0 years experience on sealed systems. There's a hundred things that can go wrong if it's not done right. If you get a well qualified refrigeration tech you shouldn't have any problems. Good Luck and keep us posted.
Thank you. The tech is coming on Tuesday. They say they have experience. I will certainly update.

Incidentally. In this pic, the pipe with the black stuff on it, with the thin wire on top, is the pipe that ice's over.
What is the purpose of this pipe?

(Capillary tube? Is a blocked capillary or defective filter drier, if there's one, possible]

Black capped pipe.jpg
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That's the cap tube where it enters the evaporator. The other end of the cap tube is the filter drier.

Ok..tech came out. He seemed knowledgeable in my limited experience and took the time to explain what he did.

He said my pic of the ice atop the coils was very helpful.

One of the first things he checked was the drip tray.
It was full of water and gunk.
He said this indicated a leak, (I think he indicated in the heating coil underneath.) and probable contamination of the sealed system throughout. Possibly from oil breakdown in the compressor.

He recommended complete sealed system replacement. He said that even if they could locate a problem in a specific component or area and just tried to fix that then the general contamination could then cause the problem to arise again.

$115.00 for the initial diagnostic call.
Estimate to complete the work @ $2.2K.

Ouch but oh well...
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Call me curious, did he connect a set of refrigeration gauges to the system and read the pressures? I don't agree with a lot of what he told you but I wasn't there. I wish you luck!
He did not, and I didn't necessarily agree but it's beyond the limits of my experience to dispute. (High Energy Physics is more my thing...)
He has quoted @ $2,700 to replace :

Heat Exchange Kit
Heater Pan

Could I be getting ripped off? I don't know and I don't have the capability to dispute unless I try to pay for an additional opinion but I don't know if that's worth it?
I'm in the town of Lancaster, north of Los Angeles and the local service agent refuses to service built-in's
When I called Thermador they first suggested another tech in Bishop. 200 miles away but I'm sure they must have agents in Los Angeles.
Here's the quote.
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You're getting ripped off big time! Water and gunk in the drip tray indicates there's water and gunk in the drip tray and that's all it indicates. He doesn't know any more than what I've already told you. There's no way of knowing if there's a leak or a restriction without connecting a set of refrigeration gauges to the system. There are no contaminants in the system unless the compressor was a burnout and that didn't happen or if there was a leak in the evaporator and all the refrigerant leaked out and the low side pressure went into a vacuum then it's possible it could suck in moisture if the conditions were just right. Even if it did, a filter/drier is installed in the system to catch any contaminants.

I've been in this business for a long time and I've seen it all. Here's what I gleaned from the last four posts. The guy is either a crook or doesn't know what he's doing. Or the more likely, a little of one and a lot of the other. He's covering his ass by giving you a high quote for replacing everything even if it's not necessary. He's also giving you a high quote in hopes you'll turn it down. If there is a leak, it could be almost anywhere and it could be two year leak. In other words the leak could be so small it doesn't leak out enough refrigerant to affect the cooling for two years or longer. If it's a restriction, changing the filter/drier and recharging the machine might be all it needs. I would not have this company repair your refrigerator. Try to find someone more qualified, if that's possible.

For $3000 I can drive there from Utah, fix your refrigerator, and return to Utah with a hefty profit...lol
Thanks...you make sense...
But if I find someone else willing to come out I don't know if they'll just say the same..
I'll make some calls...
I found someone else to come out. Talked to him on the phone. Sounds like he's got all the proper diagnostic gear.
He says he's got the equipment to determine if there's a leak and to locate it if there is one.
New guy came out.

He had a heated diode detector and rapidly isolated a leak in the evaporator coil.
Quoted 2.3K total to fix, but with the initial diagnostic call refund that will take $70.00 off.
States he can source components locally and get the job done Sun/Mon.

Says he will replace coil, filter/drier, underneath heating coil.
He says even though it's a built-in he will need access to the back but that's included in quote.

Wife told me to go ahead.
Well at least you saved almost $500 with the new guy. I still think that's a little high but that could be the going rate in California. Sealed system repairs are almost all the time quoted out as a flat rate. They don't break it down. And they shouldn't. I charge a flat rate to replace a compressor in a standard refrigerator regardless of brand or model. That's so Joe Customer down the block pays the same amount for the same repair. I got curious and broke it down. Just for kicks I looked up the parts he's replacing. (I rounded up) Evaporator $250, Heating coil $120, Filter drier $40, Service valve $30 Refrigerant, welding and shop supplies $150. Those prices are retail and not what he's paying. So $1700 for labor seems kind of high even for a built-in machine but like said, sealed system repair costs vary from state to state and area to area. I just realized, I should probably just keep my mouth shut and not cause any problems....LOL As long as you're happy and the wife is happy, it's all good. Happy wife, happy life! Good luck my friend and let us know how it goes.
Thanks Rick...I do appreciate the support.
Incidentally...his quote lists @ 950 for the parts and 1300 for labor.
He said it would be @ 4-6 hour job, maybe longer.

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