This was super helpful, thank you!! My AO Smith hybrid water heater ran into the same problem. They were less helpful at troubleshooting the issue over the phone, but this pointed me in the exact direction I needed to go.
I might be up in the night, but I'm jumping on a few of these threads to propose that people move that ambient air temp thermistor AWAY from the discharge line. You can see the location really well in your video at 3:59. I've seen it in the same place on mine as well as several others in similar videos. I don't know if it's responsible for the error, a contributor, or nothing at all; but I could tell I was getting anywhere from 2 to 5 degrees of high bias on my aT (and that was after the fan started, it was a lot more when fan wasn't running). I replaced my thermistors, but I tested every one I took out and every one I put in, and did not see any of them test bad. So assuming my testing was accurate, this is the only thing I changed that was material and I haven't had the error in a couple days of hard use. Previously I couldn't go more than a couple hours.
A quick update I still have not gotten the error since I made this change. I have gone into diagnostic mode a few times and I have seen dT as high as 198, and I know that the temperature at which it kicks out is 200. So if a few degrees aT causes a few degrees dT then seems plausible to me.
Just swapped my 3 thermistors (not ambient). Performance characteristics are much better. Previously, once I started using hot water in a day, the compressor ran and ran. Eventually the hot water would be restored or the energy saver mode would give it a heating element boost to help finish. Now it finishes heartening between uses throughout the day and no element boost! I put all the thermistors in an ice bath. New ones all measured 33.0K. Two of the originals were 28.5k and one was 10ish k (kept getting different readings). Assuming they use temperature differentials, it dont think the absolute differences are a big deal. But the evaporator thermistor was way off the mark. Note my main symptom was the coiled freezing up. I’ll keep watching it, but current results are very positive.
Thanks for the video, mine just shut down this morning. Discharge temp high. How do you access the codes? Mine is also just over a year old. It seems to run all the time and the app says I'm out of hot water but there seems to be plenty when I use the hot water. I think probably the thermistor also.
Sorry to hear that! Running all the time may be a low charge. The best thing to do is call Rheem using the number on the water heater. They will ask for the serial number and if it’s less than 10 years old they walk you through the diagnostics. Easy peasy and excellent customer service. I hope it’s an easy fix!
WHAT?? Did you see that. Why are the OEM original wires multi color while the replacement wires are ALL WHITE? Is Rheem sending a upgrade to faulty manufacturing parts? I have a rheem hp wh thats 2 years old and had the same code. They sent me the same white wired replacement sensors for the same 3 they told you to replace. Anyways. Thanks for the video. I’m not alone.
This was super helpful, thank you!! My AO Smith hybrid water heater ran into the same problem. They were less helpful at troubleshooting the issue over the phone, but this pointed me in the exact direction I needed to go.
Glad it helped!
I might be up in the night, but I'm jumping on a few of these threads to propose that people move that ambient air temp thermistor AWAY from the discharge line. You can see the location really well in your video at 3:59. I've seen it in the same place on mine as well as several others in similar videos. I don't know if it's responsible for the error, a contributor, or nothing at all; but I could tell I was getting anywhere from 2 to 5 degrees of high bias on my aT (and that was after the fan started, it was a lot more when fan wasn't running). I replaced my thermistors, but I tested every one I took out and every one I put in, and did not see any of them test bad. So assuming my testing was accurate, this is the only thing I changed that was material and I haven't had the error in a couple days of hard use. Previously I couldn't go more than a couple hours.
A quick update I still have not gotten the error since I made this change. I have gone into diagnostic mode a few times and I have seen dT as high as 198, and I know that the temperature at which it kicks out is 200. So if a few degrees aT causes a few degrees dT then seems plausible to me.
Just swapped my 3 thermistors (not ambient). Performance characteristics are much better. Previously, once I started using hot water in a day, the compressor ran and ran. Eventually the hot water would be restored or the energy saver mode would give it a heating element boost to help finish. Now it finishes heartening between uses throughout the day and no element boost!
I put all the thermistors in an ice bath. New ones all measured 33.0K. Two of the originals were 28.5k and one was 10ish k (kept getting different readings). Assuming they use temperature differentials, it dont think the absolute differences are a big deal. But the evaporator thermistor was way off the mark. Note my main symptom was the coiled freezing up. I’ll keep watching it, but current results are very positive.
Glad you figured it out. Its annoying, but once fixed these units are great!
thank you for posting this. I am doing the same DIY repair soon.
Glad it helped
Thanks for the video, mine just shut down this morning. Discharge temp high. How do you access the codes? Mine is also just over a year old. It seems to run all the time and the app says I'm out of hot water but there seems to be plenty when I use the hot water. I think probably the thermistor also.
Sorry to hear that! Running all the time may be a low charge. The best thing to do is call Rheem using the number on the water heater. They will ask for the serial number and if it’s less than 10 years old they walk you through the diagnostics. Easy peasy and excellent customer service. I hope it’s an easy fix!
thanks! do you need network for them to diag, or how to diag? mine one non stop
Diagnosis happens over the phone. I don’t believe they need to be on a network. I read off the results.
WHAT?? Did you see that. Why are the OEM original wires multi color while the replacement wires are ALL WHITE? Is Rheem sending a upgrade to faulty manufacturing parts? I have a rheem hp wh thats 2 years old and had the same code. They sent me the same white wired replacement sensors for the same 3 they told you to replace. Anyways. Thanks for the video. I’m not alone.
I did notice that when I received them. No idea on why. But it did fix the problem, so now I move on to the next one…