It leaks
It works fine, but the house is too dry
It's noisy
It doesn't run at all
There's no water in the reservoir
There's no water flowing through my flow-through type filter pad
The pad doesn't spin
More about humidifiers
Humidifier replacement parts

The water supply attached to your residential humidifier provides the moisture that's necessary to adequately humidify your home. The water supply may be turned on by the humidifier to fill a reservoir tank--or it may continuously flow over a filter medium whenever the furnace blower is on.

• If the humidifier has a reservoir, when the water collects to a certain depth in the holding tank/tray, a mechanical float ball rises to the surface of the water, shutting off the water supply. If the float mechanism sticks or is otherwise defective, the water may not shut off properly--so the tank/tray overfills and spills out onto your floor. What you probably need to do is replace the entire float mechanism. You could be successful with cleaning it or replacing one or two components, but the cost of a new float is comparable to the cost of some of its individual components.
  
• If your humidifier flows water continuously while the furnace blower is running, check all hose and/or tubing connections to be sure that everything is tight. Then, open the cover and make sure the filter is in its proper place and position. Finally, make sure the water drain line/tube is unobstructed and unclogged.
  

Furnace-mounted humidifiers have one major drawback, they humidify only when the furnace blower is on. If your house is well insulated and you have a high-efficiency furnace, the blower may not run long enough to evaporate an adequate amount of water into the air. Then you have two options:

• Set the furnace fan to run continuously.
• Supplement the furnace humidifier with a freestanding humidifier.

While humidifiers run, they either add water to the filter pad or reservoir, or they spin their cylindrical pad through the reservoir. The solenoid that allows water to flow into the flow-through type can be noisy, as can the motor that spins the pad in a reservoir. There's usually no remedy for this noise. If it's very noticeable or bothersome, a qualified heating and cooling contractor may be able to help.

If your dehumidifier does nothing at all, the humidistat may be set too low or too high. Try turning the humidistat to a setting calling for greater humidity, then turn your furnace up 5 degrees higher than the current room temperature. When the furnace blower turns on, the humidifier should function. If it doesn't, you may have lost power to the unit, or one of the electrical components may have failed--the valve, motor, or step-down transformer. If these are okay, check for a problem in the water supply, or contact a qualified heating and cooling contractor to diagnose and fix the problem.

If there's no water in the reservoir, first make sure that water is getting to the humidifier. The humidifier must have a good stream of water available to it. If there's water in the water line but the reservoir doesn't fill, replace the float mechanism inside the humidifier.

If there's no water flowing through the humidifier filter pad, first make sure that water is getting to the humidifier. The humidifier must have a good stream of water available to it. If there's water in the water line but it's not flowing to the pad, you may have a stuck, clogged, or defective water valve.

Often these valves can be cleaned. Try removing the water line from the inlet side of the valve and cleaning out the valve. There may be sediment clogging the orifice. If it's clean, check the coil with an ohm meter; it may be burned open, or the humidistat transformer may have failed. If none of these is the problem, we suggest you contact a heating and cooling technician for further assistance.

A small motor on the side of the humidifier spins the rotating filter pad on the reservoir type of humidifier. If it doesn't spin, adjust the humidistat to make sure it's calling for more humidity. Then turn on the furnace. When the furnace blower is on, if the pad still doesn't rotate, the motor may be defective. If so, you need to replace it.