Uponor zone module shows zone valves on, but not calling for heat

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Joe B

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I am trying to piece together the behavior of my six-zone Navien CH240 hyrdonic system. Heat is radiant floor pex tubing under concrete. Thermostats are Uponor WT 1, one thermostat per zone, wired to a pair of 3-zone Wirsbo zone control modules.

I am trying some experiments. Today I have a zone, "Bath 2," whose thermostat shows it has clicked on and is calling for heat. But the control module only shows the red LED is on. The manual says that the yellow/orange LED indicates that the zone is calling for heat.


Why would the control module show that the zone is not calling for heat, but the valves are open sending heat to that zone? I can understand if the zone stopped calling for heat, that the yellow LED would go off and the control module would, soon after, close the zone's valves, and that the red LED might stay on in the mean time. But this zone's thermostat shows it is calling for heat, so why on earth would the yellow LED not be on?

Thanks for any insight in helping me learn about my system.


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Peace valley missouri
Yellow light call for heat, red light power to zone valve. Have a volt meter between the two top wires if thermostat is calling between wires 0 voltage if thermostat is satisfied 24 vac. Bottom termials power to actuator is y1 & y2. Thermostat satisfied 0 voltage calling 24 volts. Light stays on bad board.
Hey, wait a minute.

This is awkward, but...

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