This problem typically starts with an ERROR 001, ERROR 038, or ERROR 039, but your Navien could show a number of other errors caused by the faulty flow sensor. We will discuss further below.
First thing, if you need hot water immediately, try unplugging the system wait 30 seconds, plug it back in. This resets your tankless and may give you hot water again for a quick shower or temporary use. Don’t forget though, this type of error typically will reappear again shortly.
We recommend you call a certified technician to replace your flow sensor, you are liable for any damage you cause to yourself, your tankless, and it could void your Navien warranty. That being said we understand that homeowners are squeezed in every which way for every penny they have, this is a fairly easy replacement job and the parts are cheap as well.
Replacement Navien Flow Sensor
- NPE/S model tankless – Part # 30011534A (out of stock)
- NPE/A model tankless – Part # 30008571A
- All other models* – Part # 30010537A
*Replaces BH1406004F, 30002669A, 30004802C
How To Replace The Flow Sensor
There are a few things to mention here.
- Sometimes the flow sensor just needs to be cleaned up and reinstalled to correct the error. If you have heavy scale and calcium in your water a good cleaning may be all that is necessary.
- Occasionally something like an error 012 will display indicating a flame loss, this could be indirectly caused by the flow sensor. If your flow sensor is working intermittently the tankless could read no water flow cut the flame but then get flow from the flow sensor again. This situation could theoretically then throw a flame loss error.
- Clean the water inlet filter/s. If these get clogged or gummed up water flow will slow to a trickle and you might get a false negative flow sensor error.