Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Navien NCB-190 cycling on/off

GeneBA
GeneBA Member Posts: 17
edited February 2023 in Domestic Hot Water
My brand new NCB-190/080 is turning gas burner about every 5 minutes or so. I noticed the supply temp is exactly at 132F, burner stops when supply reaches about 160 F. By supply, I mean radiant heat, 2nd loop.

Zone valves and system pump for floor heating are connected to the boiler but the thermostats are physically turned off, not calling for heat and zone valves are positively closed.

I also hear wash cycle every 5 mins or so, immediately followed by zone valves clicking. The boiler is supplying 24VAC for a brief second. It shouldn’t be doing that.

Cycling only started after plumber connected floor heating. With just DHW on, I can’t recall the boiler waking up on timer or sensor all night long.

How do I turn this continious madness off? Is having an external Taco zone controller more reliable then using Navien’s built-in zone stuff or this is unrelated.

Thank you, Gene

Categories