NORITZ CB BOILER BURNER NOISE - Noritz Water Heaters

MAke sure your flu is not making any 90degree turns. Use 45degree turns only. Error 99 is a combustion error. Usually referring to a blocked/obstructed flu. That said, a flu wit a lot of 90degree turns can act like restrictions to tankless heaters. If the flu i straight and clear, then you have a burner problem. Somethign you want Noritz to deal with.

F1 means burner is at fault ,lack of pressure, best to call viessman or the installer back as if its a new boiler it has a five year warranty

Loud rumbling noises are often caused by either water boiling in the burner or by entrapped air in the system. To help prevent water boiling make sure that the boiler system has a pressure between 15 - 30 psi. Also check for sufficient water flow and remove any sediment from the in-line filter. To remove entrapped air, install an automatic or manual air vent at the highest point in the heating system and also make sure you have a properly working micro-air vent installed. With the unit turned off and cooled down, you can also try flipping the lever on the pressure relief valve to try and flush out any air in the heat exchanger . Hope this helps.

reset circuit breaker fully off the on
power outage can call surge
check fuse on circuit board

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odd noise like popping or singeing fire....clicking noises.....sounds like you have a water leak putting out the pilot.......or your thermo coupling is bad....or the noise is the tank full of calcium buildup and that will make noises when the burner is on

error code 123 is a flame rod sensor problem. Chances are the flame rod is sending a weak signal to the control unit. Check for a loose flame rod electrical connector. Peek in the flame inspection windows to ensure there is a proper flame on that side of the burner. If non of the above then try removing the flame rod and cleaning with 400 grit sandpaper or replace it with part order # SKC7448 (called an Ignition plug ELV & Packing EHK SETV)

Check thermocouple , sounds like it's not sensing flame.

F76 is a communication error between two quick connected heaters. To clear the code, disconnect power from both heaters, wait 20 seconds, then reconnect power.

try cleaning the flame rod and igniter with a cloth (do not use sand paper or emery cloth). Look for evidence of a water leak inside the unit.

How many faucets do you have on when this happens? Turn on more than 1 and if it still does the samt thing than I would check to see if the inlet water screen has debris in it. Valve off the unit and look at the inlet water side and theres a screeen that you should be able to remove and clean undeneith some running water and then replace. Good Luck