Setting blower speed

[mkirsch1]

Following up on my register temperature issue yesterday.

A couple of people have suggested to look at blower speed. Mine is set to, "Don't stand near the cold air ducts, you'll get sucked in!" That is, the fan seems to be running at high speed when the furnace is running.

I can find no fan speed control, either on the unit itself or at the thermostat. The only fan controls are at the thermostat and those consist of two selections, AUTO and ON.

I realize that the fan controls may be in different places for different units, and I apologize for not being able to provide an exact model number, but what would be the telltale signs of a fan speed control? What would one look like? As I said, there is nothing either on or in the unit that is so obvious as to say "Fan Speed Lo Hi Off." There's a gas valve behind the access panel. That's it.

[Art Todesco]

Many (most?, all?) require rewiring the blower in the control area, if it is indeed a multi-speed blower motor. There is usually a common lead and leads for each of the available speeds, usually 3 or 4. Sometimes, if there is heat and AC, it can be wired for different speeds for each. Obviously not a job for the typical homeowner.

[Speedy Jim]

As Art noted, the motor probably has a number of leads brought out for the various speeds. They will be color-coded.

Look on the door panel or inside the furnace for a wiring diagram which will show the connections.

Jim

[TKM]

If there's no electrical way to change the blower speed, it can be done by changing belt and pulley sizes (assuming a belt drive arrangement). That's usually a job for a furnace technician, however.

TKM