• Please note, some of the links on our site are affiliate links (Learn More)

FIXED Sub-Zero 650 refrigerator with intermittent warming of refrigerator (technician already came)

Status
Not open for further replies.

william13

Premium Member
Joined
Mar 14, 2021
Messages
30
Location
florida
Model Number
650
Brand
Sub Zero
Age
More than 10 years
I am a newbie appliance novice with an electrical background. I own a Sub-Zero 650 refrigerator. Recently the refrigerator portion became warm up to 55 degrees.
I had a qualified technician over who tested all the usual culprits and found no issues. During his examination the fridge suddenly started to work and dropped the temperature all the way down to 34 degrees. He hypothesized the control board may have bad relays and should be replaced but there was a 2 weeks wait period until he could give me a next appointment. Mean while the temp is set at 34 but crept back up to 46 and then fell back down to 40 but will not go below and I was hoping it would go to 38 degrees.
I plan on letting him replace the board but I am wondering if a "start relay" problem could present this way. (or maybe something else).

P.S. The compressor reads "Embraco 30 EMI HER"

Thoughts ?

Thank you

One other observation: higher shelves may be 3-6 degrees warmer but I don't know if this is normal
 
Last edited:

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
44,797
Location
Murray, Utah 84107, United States
I'll assume the freezer section is working without issues. Everything we discuss will be for the refrigerator section only. Make sure the evaporator fan motor is working. Is the compressor running? Compressors normally run warm to very warm. A compressor that is hot to extremely hot usually indicates a problem with the sealed system. Are there any error codes or is "service" flashing on the display? Do you hear any "clicking" sounds coming from the compressor?
 

william13

Premium Member
Joined
Mar 14, 2021
Messages
30
Location
florida
Thank you for your reply. Yes refrigerator with issue. Freezer fine. Evaporator fan runs. Compressor running without clicking. Compressor warm. No error codes or service. Was fully inspected by qualified technician who found no issue with compressor, both fans.
 

william13

Premium Member
Joined
Mar 14, 2021
Messages
30
Location
florida
OK it sounds like the board.
So reason I mentioned that I have an electrical background is that I have been an audio enthusiast for 30 years and I am constantly working on pcb on amplifiers etc. Never on fridges. I could easily replace the 4 relays on the board for 1/20th of the price of a board and also test the capacitors look for burnt spots etc.

Just wondering what your thoughts are? Would a bad relay cause a tendency for fridge to be warmer than settings?
 
Last edited:

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
44,797
Location
Murray, Utah 84107, United States
There's quite a few members that have repaired boards. Service techs don't go past board level for two reasons. The biggest reason is it's not cost effective the other reason is there are no board schematics available. That area is more of an electronics techs field. I've repaired boards in my own appliances, monitor, and TV, but it's hit or miss. I can tell a blown cap or burned component but that's about it. Sometimes I'm successful and sometimes not. If you decide to go that way, good luck! You might try reaching out to tortillasoup for some help.
 

william13

Premium Member
Joined
Mar 14, 2021
Messages
30
Location
florida
Thanks. I have a couple more questions. Would a bad thermister also cause the fridge to intermittently warm?
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
44,797
Location
Murray, Utah 84107, United States
It's possible but thermistors don't usually go intermittent. They are more likely to short or open. To check the thermistors, place them in a small glass of crushed ice and water. That will bring it close to 32°F. Wait a couple minutes and check for 30,000Ω to 33,000Ω. Hold it in your hand to warm it to room temperature then check it again at 32°F. If you get the same reading it's doubtful it's intermittent.
 

william13

Premium Member
Joined
Mar 14, 2021
Messages
30
Location
florida
What I dont understand is how a defective board can cause fridge run in the low 40 degree temp despite temp being set at 34 degrees. How mechanically does this happen? I mean can a bad relay present this way?
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
44,797
Location
Murray, Utah 84107, United States
It's probably the MICOM on the board causing the problem, not a relay. But like I said, I don't do boards.
 

william13

Premium Member
Joined
Mar 14, 2021
Messages
30
Location
florida
I am working under assumption its the board but I kind of want to make sure. So I have not opened my fridge for a day and the temp is set on 34 but the fridge temp is 40
I put a piece of paper in the freezer door seal and it was hard to pull out. In the fridge the paper pulls out easy but the insulation looks fine.
Could my issue be as simple as that? How can I be sure?
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
44,797
Location
Murray, Utah 84107, United States
If the door seal is sealing against the cabinet, it's good, paper or no paper. I don't know who came up with that dollar bill thing...lol. If you want to know if there's an air leak, put a bright flashlight inside the compartment, close the door and turn off the kitchen lights. No light coming through the seal, no problem.
 

william13

Premium Member
Joined
Mar 14, 2021
Messages
30
Location
florida
So after two days not opening fridge it is down to 38 degrees but set at 34 through panel. Spoke to the technician who ordered the control panel which is not in yet.
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
44,797
Location
Murray, Utah 84107, United States
Are you using a good thermometer to measure the temps? DMM with a temp adapter works best. That or infrared laser gun.
 

william13

Premium Member
Joined
Mar 14, 2021
Messages
30
Location
florida
Thanks ! I will get a dmm attachment. I was using a digital thermometer that has a bottle of what I think is green alchohol attached. It reads the room temperature correctly. By the way I removed the refridgerator thermister and put in ice water and it did read 30,000 ohms which is good. In the past when I shut the door it would create and instant vacuum and the door would be hard to open for 30 seconds. This is no longer true. Also I noticeds slight peeling of paint under the seal lower face frame to the left of center. I keep on wondering if the fridge can get down to 40-42 degrees is the board really the issue. I did not see light emerging from the fridge when I did the light thing however. These are complex units ...I understand a defrost heater for the freezer can cause fridge warming and this is controlled from the "board".


Addendum: When I semi-slam the door I do get the vacuum effect
Bill
 
Last edited:

william13

Premium Member
Joined
Mar 14, 2021
Messages
30
Location
florida
I am sorry to go back and forth but the more I inspect the fridge the more I see.
The door does not shut perfectly. On the non hinge side, when the door is shut I can not push the top upper corner in at all. However the bottom non hinged side can be depressed 6 mm. In other words the door does not close 100% flush. I did the light thing once more. This time I made the room pitch black but shutting off the water cooler and the rheostat both of which have LED. Under pitch black circumstances I can see a very faint glow from the light I put in the fridge. I can attach pictures tomorrow on the slight door protrusion bottom right side but is there a fix?
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
44,797
Location
Murray, Utah 84107, United States
Ahh...overthinking and second guessing .... been there, done that!
6c2ba386.x120.gif
 

william13

Premium Member
Joined
Mar 14, 2021
Messages
30
Location
florida
Glad you understand. It's a little embarassing to keep on changing my story but this is a learning process for me. You are patient and thank you for your help. The thermometer I am using turns out to be very accurate. I did not realize that the 650 Sub Zero also has a thermometer read out on the membrane panel. I thought it was always reading what my "set point was" and it does do this for 10 seconds. After it reads the temperature of where the thermister lies. So my fridge does get to the "set point" according to the panel thermastat. The only issue is that my thermometer reads 3 degrees higher ie thermometer on panel reads 38 degrees and the thermometer I placed reads 41 degrees. I believe food spoils above 42 degrees so I want to know if the "true temp" is 38 or 41. Yes I plan on placing other thermometers.
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
44,797
Location
Murray, Utah 84107, United States
I use an infrared laser thermometer that is extremely accurate and if I shoot the top, middle, and bottom of the refrigerator section, I'll get three different measurements that can vary as much as 5°. Read the temperature from the location of the thermistor.
 
Status
Not open for further replies.
Top