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Noritz Combi Boiler CB199-DV - no heat, 3 way valve issue??

Hello - We have a Noritz Combi Boiler CB199-DV (run on NG). We purchased the home summer of 2020, the unit was installed the month prior to purchase and this is the first winter it has been used - we live in New England so it has been used fairly regularly since November. After reading through these threads and an initial review from an HVAC tech we have confirmed the likely issue is with the 3 way valve. Our hot water works without issue, however no radiant heat (thermostats working and activating pumps etc - seems only cold water flowing through system).

We were able to reach Noritz this morning. They didnt ask many questions - based on the descriptions they confirmed likely valve issue and are sending a new 3 way valve covered under the warranty. Is anyone aware if Noritz covers cost of labor for any replacement of this valves (unit installed ~ 7 months ago)? We are not sure if this is an easy replacement or if it will be a costly labor expense?

In the meantime - we have had some success restarting the unit to get the heat working, though every time we utilize hot water it shuts down the radiant heat again. Are there any ways to manually bypass this to allow for radiant heat (while waiting for replacement part and install)?

Running space heaters and hoping to keep the temp up in the house until this can be fixed. Thank you in advance for any insight!


  • Ironman
    Ironman Member Posts: 6,868
    edited February 2021
    What type of radiation do you have? Radiant floor? Baseboards? Free standing cast iron rads? The reason that I ask is because most of the 3 way valve failures have been due to connecting the boiler to an old system (particularly on that has sludge in it) without proper flushing and filtration/dirt removal protection installed on the return line to the boiler.

    Manufacturers typically offer no labor warranty; that's the responsibility of the contractor.

    The replacement of the part should not be that difficult for a competent tech. There are online videos that detail it. If he can't find one for Noritz, the Laars version is basically the same.

    Unplugging the cable to the valve while it's in space heating should prevent the valve from shifting to domestic. I'm not sure how the control will respond to that. You could just simply close the cold shut off valve at the unit. As long as there's no domestic flow, it won't shift to domestic.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.