Noritz error code 16

[PhileFriendly]

We have a Noritz N-084M-DV tankless water heater that is about 15 years old. Early this year we started having an issue where periodically the unit would stop, giving error code 16. If I turned it off and on again, it would work for a few days before the problem recurred. Unfortunately it happened more and more frequently until eventually it just wouldn't start - technician checked it out and diagnosed it as having a failed thermal fuse, which he replaced and the unit started working fine again. Fast forward to now, many months later and we have started to get the dreaded Error Code 16 again.

It seems to me likely there is some other issue at the root, and I'm reluctant to do another thermal fuse replacement if that is only going to buy me another half year with the unit. I have descaled the unit and it was cleaned up when we did the last fuse replacement; any thoughts on what else I might look into to keep this unit running?

Thanks in advance (and Merry Christmas)!

 

[John Gayewski]

Your lucky your heater has been running this long.

 

[Sponsor]

 

[PhileFriendly]

Your lucky your heater has been running this long.

Yeah, the guy who I had out a few months ago for the first fuse replacement said that it is almost a light-duty commercial unit, and thought it would be pretty robust still - definitely didn't think I'd be back to the same problem 6 months later. Then again, I wouldn't have bet on the Seahawks having a losing record this season either.