Calling for heat but no blower

[always something]

My T'STAT is calling for heat but the blower is not activating. The boiler is turning on and sending hot water to the air handler. The blower works as it runs when the T'stat is turned to on and the AC setting turns the same blower on.

Thoughts?

Cheers!

[Admin]

If you turn the thermostat fan from AUTO to ON does the fan run?

What model of air handler do you have?  It could be a faulty relay on the control board.

[always something]

Yes, blower works fine when set to On. Also, the AC setting activates the same blower in the Auto setting.

Unit is a Carrier. House built in 1988.

Thanks

[always something]

Here is a picture of the nameplate.

[always something]

Here are some additional photos of the controls. Not much to this one.

[Admin]

Is this a heat pump system?  Or do you only use the hydronic heating?

There's probably an issue with that Honeywell control.  Turn the heat on and try to turn that dial down and see if the fan starts.

[always something]

In a separate room is a slant fin boiler. This pumps water over to the handlers for air flow upstairs. It also pumps water throughout the basement as a hydronic like system. Adjusting that knob does nothing while calling for heat.

What is the device supposed to do or protect? It is measuring the temperature of the hot water pipe coming into the air handler.

Suggestions on how to get a replacement part number for the Honeywell controller?

Appreciate the help.

[always something]

Found the Honeywell part number. T675A/ Looks like a simple R&R project.