Hisense Dual-Zone Chest Freezer - Too Cold In Fridge (FC-33DT1HA)

[firefox15]

Model Number

FC-33DT1HA

Age

6-10 years

I have a unique chest freezer from Hisense. It's 75% freezer with a 25% fridge compartment. Items in the fridge compartment are getting too cold regardless of what I set the panel to. It doesn't seem to matter if I set it at 40 degrees or 50 degrees, the inside is consistently around 30-34 degrees with liquids freezing.

The compressor is nearly always running, and the freezer is the proper temperature (around 0-4 degrees). I defrosted the entire thing with no real change. Unfortunately, I cannot find a service manual or much at all to help with troubleshooting this. I have access to both thermistors, but outside of that everything seems mostly sealed. I can see the compressor (a Samsung) through the vents at the bottom.

I thought maybe changing out the thermistor in the fridge side could be worth trying, but since I cannot find a service manual, I have no idea what kind of thermistor resistance I would need, etc. Is there anything I can do to try to fix this, or should I just throw it in the trash? I cannot imagine it is worth calling for a repair on something nearly 10 years old, so I thought I would post here to see if anyone has ideas.

Thanks!

 

[Dan O.]

I have no idea what kind of thermistor resistance I would need, etc.

I don't know either. I can't even find exploded parts diagrams to look up how it might be designed so it's difficult to suggest anything. Try contacting Hisense to see if they can provide anything.

I found a parts list for a model number that is close but no diagrams.

HISFC33DT1H4A Parts List

FC33DT1H4A Hisense Replacement Parts - ApplianceParts.com

applianceparts.com

It does list a "Solenoid Valve" which if in the refrigeration system might be how it controls the cooling of the individual sections. Possible culprits might include the sensors, the electronic control and that solenoid coil (if used) or the valve body the solenoid is part of.

I didn't see any sensors or thermistors listed to see if they might be the same.


On a side note, can you post a photo of its model and serial tag? I'll try to see if it could have been made by a secondary company that might be able to provide some assistance for it if Hisense can't.


Dan O.

 

[firefox15]

Thanks, Dan. I'm attaching some photos I was able to take of the unit. I think I see where the thermistors plug in, so I could probably test the resistance with a multimeter, but I'm not sure there is a point if I don't know what thermistor to replace it with. I see there is a basic diagram, so maybe that helps . . . somehow? I appreciate your help!

As a side note, I'm not even sure how the fridge part is cooling at all. The thermistor appears to be the only thing in the compartment that isn't sealed. I'm used to seeing a baffle that opens to allow freezer air into the fridge compartment, but that definitely is not happening here.

 

[Dan O.]

1. It looks to be a Hisense made unit as far as I can tell. I do at least see a phone number to call for support.

I'm not even sure how the fridge part is cooling at all.

I believe I see 2 capillary tubes which should indicate 2 evaporators.

What is the white part illustrated below? Is it attached to the refrigerant lines? Any wires doing to it?

I think I see where the thermistors plug in, so I could probably test the resistance with a multimeter, but I'm not sure there is a point

It's possible they're both the same. If they measured the same when both were at the exact same temperature might indicate good. If they measured differently, that wouldn't necessarily mean they were defective though. If possible, try to test them while in a glass of ice water.


Dan O.

 

[firefox15]

1. I looks to be a Hisense made unit as far as I can tell. I do at least see a phone number to call for support.

Oh man, I have to laugh. I tried to call the number and it literally went to one of those scam lines where it said I won a free vacation or whatever. Needless to say, my impression of Hisense isn't great at this point. I submitted a ticket on their ticket portal to see if they have any information, but if their phone number is any indication, I doubt I'll hear back.

What is the white part illustrated below? Is it attached to the refrigerant lines? Any wires doing to it?

Yes, the white part has refrigerant lines going to it along with some wires. It looks like a relay or something? There is also the control board behind the compressor where both thermistors, the main wiring harness, and more plug into.

It's possible they're both the same. If they measured the same when both were at the exact same temperature might indicate good. If they measured differently, that wouldn't necessarily mean they were defective though. If possible, try to test them while in a glass of ice water.

So, I think they are the same thermistor. When I isolated them, the freezer was reading around 48k, and the fridge was reading around 22k. Of course, without a chart, they don't mean much to me, but they are reading something.

When I tried the ice water test on the freezer side, it responded pretty quickly and adjusted to 23k within 30 seconds or so. The fridge side seemed less responsive, but I'm guessing that's because it was pretty close to that temp already (as things keep freezing). After 30-60 seconds, it was reading around 23k, so similar to the freezer. When I rolled both of them in my hands, they adjusted to 14k or so based on my body temp.

Again, without a chart, I feel like I'm pretty blind. Maybe the fridge side is tempermental, but it's hard to say. I feel like thermistors are cheap enough that if I could find one I would at least try changing it out, but since I have no idea what this is (and I can't find any identifying marks on it other than cable jacket markings), I would have no idea what to get. Think I should throw in the towel if I don't hear back from Hisense, or is there anything else I should try?

 

[Dan O.]

so similar to the freezer.

Than they are likely the same... and sounds like they're likely good as well.

the white part has refrigerant lines going to it along with some wires. It looks like a relay or something?

It will be a valve for the refrigerant. It likely stops refrigerant from going to the fridge section when it is cold enough. In such a design if the valve was staying open too much, it could cause the fridge section to get too cold.

You can read how a water valve works at the following link. In your case the valve would meter refrigerant instead of water.

LINK > Appliance411 FAQ: How does a water fill valve work?


There are 2 possibilities for a malfunction in such a design. 1-The internal valve mechanism could be 'stuck' and not closing the one gas route. 2-The valve is being continually powered by the control even when it shouldn't be, causing the valve to remain open too much.

Maybe try confirming if the valve is being powered continually. (I don't know its voltage though. It might be marked on the side of the valve.)


Dan O.

 

[firefox15]

Thanks, Dan. I appreciate the explanation. I'll work on figuring out the valve situation. I'm not sure it is helps, but I changed the setpoint, waited a few hours, and then recorded the inside temp by the thermistor. These are the results:

Setpoint	Recorded Temp	Differential
21	19	-2
26	24	-2
30	25	-5
35	33	-2
40	33	-7
45	35	-10
50	35	-15

So for whatever reason, it appears the temp is tracking fairly closely at lower temperatures, but it starts getting wildly out of spec at higher temperatures. The freezer is consistent throughout all of the changes--holding around 4 degrees. Does this help pinpoint the issue at all?

 

[Dan O.]

I'm afraid I do not know what significance that might represent.