Almost all thermostats have a FAN
switch, that can be set to ON
or AUTO
. In the AUTO
position, the blower comes on when the furnace needs it (during heat/cool calls). In the ON
position, the blower will always be on. This is usually controlled by the G
terminal on the furnace and thermostat.
I'm not sure exactly what you're trying to do, so I'll cover a couple different setups
Blower on when you want
For this situation, simply connect the G
terminal on the thermostat to the G
terminal in the furnace. When you want the blower on, set the thermostats FAN
setting to ON
.
Blower on when house is too warm
If you want the blower to come on when the temperature in the house raises above a set temperature, you'll simply connect the Y
terminal of the thermostat to the G
terminal in the furnace. This way whenever the thermostat calls for cool, the blower fan will come on.
Depending on the furnace, you may be able to connect the Y
terminal on the thermostat to the Y
terminal in the furnace, and simply not connect any control wires from the furnace to the A/C unit. Most furnaces activate the blower after a predetermined (possibly programmable) delay, when the thermostat calls for cool.
Blower speed (Multi-speed blower)
Blower speed may vary based on the different functions. For example, heat might be medium low, fan might be low, while cool may be high speed. So you'll want to take that into consideration as well.
Without more information about your specific equipment, and what exactly you're trying to accomplish. It's difficult to provide more accurate, specific information.
The switch is not required for proper operation. I believe it's intended as a fail safe in the event the humidifier gets turned on without the HVAC fan enabled. In this scenario, the humidifier could theoretically flood the duct. If wired properly, I can't think how this scenario would occur, but I suppose a specific type of system failure could.
Best Answer
Leaking duct work regularly costs users 10% when leaking into non conditioned air spaces but if the leak is totally enclosed within the living space envelope it really is not helping much. Every air leak in an attic for example is saving $ if the leak is in the air handler closet it may save some but is not as effective as the attic.
As for humidifiers I like them to be easy access ultrasonic ones to verify they are working and Venturi ones to verify they have not plugged or are dribbling so for that reason I do not go crazy when sealing these up as I check mine several times a year.