Navien NR-210A Recirculation Issue

[gsoh2oman]

Hello All, We bought a house about three years ago that has a Navien NR-210A tankless water heater which was installed when the house was remodeled in 2011. We have noticed lately that the unit no longer comes on and heats the recirculated water which is set up in external mode where there is a return line coming back into the unit. (we also have a remote located in our laundry room and I have verified the time is correct and the on/off times our correct as well). I pretty much set the recirculation to come on at 5 AM and cut off at 10 PM so when I get up a little after 5 I would have pretty much instant hot water(The unit is in the crawlspace under our bedroom so I can hear the draft fan kick on when the burner engages so I know for a fact its not coming on like it used to). I have cleaned all the filters and recently did a descaling using a bucket, sump pump and cleaning vinegar and it still doesn't come on like it did. There has been no error codes come up on the PCB and I can hear the recirculation pump working just it never calls for the burner to come on therefore circulating cold water basically. Has anybody ever run into this before? I have read the service manual and didn't find anything to troubleshoot this. I also noticed that the little LCD display on the PCB which when you first power the unit on states the firmware versions and other diagnostic codes and then states the set temperature of the water heater goes blank after a couple of minutes, is that normal or do I have a bad PCB board? Also I notice the recirculation icon on the remote flashes but the unit never kicks on either. Thanks in advance for any advice.

 

[Fitter30]

Tech Support at 1-800-519-8794.
Have you tried powering down the heater for a few minutes?

 

[Sponsor]

 

[gsoh2oman]

Yes, and I just went out for a couple of hours and I unplugged the unit before I left and back in when I returned and it didn't fix it. The draft fan ran a few seconds and then cut off (burner never came on) and the recirc pump came on and at last check was still on.

 

[gsoh2oman]

I just wanted to check back in and post that I found the issue so if anyone else has the same problem they will know where to start. It ended up being the recirculation pump, I went in and removed the old one and took it apart and there was a plastic piece inside that was broken apart so I ordered a new pump and in the mean time put that pump back in the water heater but left it unplugged and placed the jumpers on the PCB board to No recirculation. Once I installed the new pump everything is working like it should again. I also forgot to mention when I was still trying to figure out the issue I finally got the E38 code when I switched the system to internal recirculation mode so according to the service manual it was either the flow sensor or the pump so since I already had replaced the flow sensor I concentrated on the pump and that was it.

 

[Joepilot]

I have the exact same problem that you did and my recirculation pump makes an unusual sound. I removed the recirculation inlet filter and found that the top filter portion of the unit was missing, broken off with the bottom of the screw in filter showing jagged plastic where it apparently broke free. So now I suspect I'm in the same position you were and I need to replace the pump.

Did you have any trouble determining the exact replacement part? Did you replace the pump portion and the motor or just some parts? Also, did you look at the filter? I'm curious if the filter was broken or if you replaced it as well. The recirc filter file is attached.
Thanks for your post. It is very helpful.

 

[gsoh2oman]

I have the exact same problem that you did and my recirculation pump makes an unusual sound. I removed the recirculation inlet filter and found that the top filter portion of the unit was missing, broken off with the bottom of the screw in filter showing jagged plastic where it apparently broke free. So now I suspect I'm in the same position you were and I need to replace the pump.

Did you have any trouble determining the exact replacement part? Did you replace the pump portion and the motor or just some parts? Also, did you look at the filter? I'm curious if the filter was broken or if you replaced it as well. The recirc filter file is attached.

Thanks for your post. It is very helpful.View attachment 67846

Actually I did replace all filters while I was in there but from what I remember they were brittle but not broken. I just remember it was a plastic diaphragm inside that recirculation pump that was torn apart and when I replaced the whole pump unit it fixed my issue. I can't really remember where I bought my pump and the filters online but I googled the part number on the pump and found the replacement pretty easy for like 150 bucks I believe.

 

[Joepilot]

Thanks. After some more research I found the same diaphragm shredded inside the pump and ordered a new pump, filter and I threw in a flow sensor just because. This should do the trick. And the pump was about $150.

So as of 30 Nov 2020, the replacement of the pump worked and the recirculation is perfect now. I changed the broken filter but did not find any of the parts from it anywhere inside so I can't explain that. I did not need to replace the flow sensor.

This was the order:

Thank you for shopping with Parts for Navien Tankless.

This automated e-mail serves as confirmation that your order has been shipped.

Shipping Summary
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Invoice #:
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Qty | Item # | Description | Date Shipped | Tracking #

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1 | 30000466A | Navien 30000466A Circulation Pump | 11/16/2020 |



2 | 30002521A | Navien 30002521A Inlet Water Filter | 11/16/2020 |



1 | 30010537A | Navien 30010537A Flow Sensor | 11/16/2020 |

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