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Trickle Flow through Noritz NRCB199DV

AmosCall Member Posts: 1
I am working on an installation for a NRCB199DV boiler.
When I connect the water hose to my system to fill/ bleed out air, I get decent flow, but only when I bypass the boiler. When I run the same setup through the boiler it slows down to a trickle.

I occasionally get error code 54, or the system will heat up but water will not push through. I have 2 zones fed by Grudfos pumps which are running, and the system is calling for heat from the boiler.

When The boiler is first turned on I get a good flow as the system goes through it's start-up routine, but then stops.

Any thoughts on why the boiler is the bottleneck here?


  • GGross
    GGross Member Posts: 803
    Looks like a combi. Perhaps a diverting valve is in the wrong positions when you are trying to purge?