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Humidifier Trouble Shooting

  1. My humidifier continues to run.  
  2. My solenoid valve is making a "chatter" noise.
  3. Water from my humidifier is overflowing to the floor.
  4. The drum of my drum humidifier is not rotating.
  5. My humidifier will not turn on.
  6. Water in the cylinder turns black.
  7. My steam humidifier fills and drains without producing steam.
  8. I already have a GeneralAire® 1042 Humidifier installed, but have a 4,000 square foot home.  Should I upgrade to a larger humidifier?
  9. I'm not getting enough humidity, and when I checked my humidifier could not see any water running through the humidifier.
  10. The humidifier is not raising the humidity levels in my home.
  11. There is moisture inside my duct.
  12. My water continues to flow even if my system is off.
  13. Water is leaking slightly at the bottom of my steam humidifier. Why?

My humidifier continues to run. 

  1. The valve might be stuck in the "open" position.
  2. Check for wiring errors.
  3. Is the unit sized properly for your home?  If it is rated for a smaller-sized home than the home in which it is installed, it will work "overtime" to reach the humidification levels desired.
  4. Check the vapor pad. If it is clogged and needs replacing, the pad may reduce the humidifier efficiency.

My solenoid valve is making a "chatter" noise.

This can be caused by any of the following:
  1. The power to the valve is less than 18v AC.
  2. The solenoid is causing a "water hammer condition" thru the water pipes (valve closes quickly and shuts off water flow, which in turn creates pressure behind the valve that has no avenue of relief).  You may want to install a water hammering device with your plumbing, or contact your local plumber to determine the best solution.
  3. The humidistat is located too close to the humidifier or the by-pass pipe. Your humidistat should be a min. of 1.5' away or greater.
  4. The humidistat could have a buildup of dust, causing a faulty reading.
  5. The solenoid valve might be dirty.  Remove, inspect and clean if necessary.

Water from my humidifier is overflowing to the floor.

Possible causes include:
  1. Vapor Pad:
    • If you install a replacement vapor pad that is not the same OEM as the factory-installed pad, it can cause the humidifier to overflow.  It is very important to use the OEM equipment recommended by the manufacturer.
    • The vapor pad might be installed at an angle or upside down; which can cause water overflow. Check the pad inside the humidifier to be sure it is installed correctly.
    • Check to see if there is heavy mineral buildup on the pad.  If so, replace the pad.
  2. The orifice and strainer may be enlarged, causing too much water to flow across the pad at one time.  If it is, replace the orifice and strainer.
  3. Check the drain to ensure it is not blocked. Clean or remove blockage if necessary.
  4. The drain hose may not be adequately connected, or might be plugged. Check to see it is fastened properly (sufficiently sloped) to the unit. Look to see if mineral buildup is plugging the hose.  If so, use a vinegar-with-water solution to remove buildup.  If it will not clean, replace the hose.
  5. Check the water flow into the humidifier for accuracy.

The drum of my drum humidifier is not rotating.

There are two possibilities for a failure of the drum to rotate:
  1. The drum motor is not getting power
  2. The drum motor has failed
Check for power at the drum motor by starting the furnace, turning the humidistat to “ON” and checking for 24 volts AC using a volt meter. If voltage is not present, the transformer has failed or there is a loose connection or the humidistat has failed. You will need to replace your transformer.
To check the drum motor, remove the cover and the drum assembly. With the humidistat ON and the furnace running place your fingers against the white motor coupling. While making the motor work slightly, observe that the drum motor rotates a fill revolution in about 1 minute. If it stops or feels as if the coupling has become disengaged, the drum motor has failed and needs replacing.
You can purchase your transformer or motor here.

My humidifier will not turn on.

Causes include:
  1. There is no electrical power.  
    What to do: Check the safety devices upstream from the humidifier for the presence of power.
  2. The on/off switch is in position 0 (Open). 
    What to do: If you found the switch to be "Open", close the switch on the panel to position.
  3. The control connectors are improperly connected.
    What to do: Ensure the connectors are properly inserted in terminal block.
  4. The fuses may be blown; there may be a transformer failure.  
    What to do:       
    • Check the condition of your fuses.  
    • Check that the proper voltage is connected and turned on.
  • Check your humidistat to be sure it is set to a level that is above your home's current humidity levels.
  • Check the wiring to and from your humidistat control to ensure it did not come loose.

Water in the cylinder turns black.

Generally this means that minerals in the cylinder have accumulated to the point that they are causing the electrodes to deteriorate. Do the following:
  1. Check for sags & kinks in the condensate hose; as they could trap condensate and cause a back pressure on the cylinder.
  2. Check the duct static pressure.
  3. Check the fill valve and inlet strainer for clogs.
  4. Check the drain pump operation.
  5. Correct installation and replace cylinder.

My steam humidifier fills and drains without producing steam.

This can occur for several reasons:
  1. Minerals have bridged between the electrodes.
    What to do:  Clean or replace the cylinder.
  2. There is back pressure from the steam hoses or duct.
    What do to:  Check the steam hoses for kinks or gullies that might be trapping condensate.
  3. The flow regulator in the fill valve is broken or out of place.
    What to do:  Replace the fill valve
  4. Water conductivity is very high.
    What do to:  Consider using a mix of demineralized water with raw water
  5. Water is foaming excessively.
    What to do: Check the cylinder - replace if exhausted.  If feed water contains silica or nitrates, install a 1 micron water filter. 

I already have a GeneralAire® 1042 Humidifier installed, but have a 4,000 square foot home.  Should I upgrade to a larger humidifier?

The 1042 is designed for homes up to 2,800 sq. feet, therefore, the humidifier was not designed to provide the humidity your home needs.

We recommend you replace your 1042 with a steam humidifier, as they offer a greater capacity for larger-sized homes.

Contact a local contractor to select the steam unit (regular or low conductivity) that best suits your home size and water conductivity level.


I'm not getting enough humidity, and when I checked my humidifier could not see any water running through the humidifier.

  • You might have a plugged orifice and / or strainer; preventing water flow through the valve.  What to do:  Remove the orifice and strainer and soak them in either CLR or Lime Away for 10 minutes. This should remove any material preventing water flow. Do NOT insert a pin or needle in the orifice to clear debris, as it has been designed to allow a specific amount of water through the opening.  You may also need to replace this part if you are unable to clear the clog. You can order the part here.
  • The water running to the humidifier might not be turned on. Ensure the water knobs/handles from the water source to the humidifier are turned on.
  • The humidistat setting might need adjusting. What to do:  Turn the control dial clockwise (to the right) all the way (the ON position). After several hours have passed, look to see if there is condensation on your windows or you feel uncomfortable. If so, turn the humidistat dial 1/16" counter-clockwise (to the left) once per day until you reach a setting that you prefer. Remember:  if your humidistat is not set higher than the current humidity level in your home, it will not deliver more moisture.
  • You many need a larger-capacity humidifier. What to do:  Review the humidity load (Gallons per Day) required for your home and your humidifier's capacity rating to see if the humidifier you installed will indeed accommodate your needs.
  • The humidifier might not be wired correctly. The furnace fan must be running for the humidifier to operate.
  • Your saddle valve might be in the "closed" position. Check to see it is set to "Open".
  • Check the water supply and make sure the water supply is set to the OPEN position on the unit.
If this does not solve your problem, contact your professionally trained local contractor for assistance.

The humidifier is not raising the humidity levels in my home.

You may want to do / check the following:
  1. Ensure you have changed / replaced your evaporator pad at the proper intervals (once per year) to ensure the greatest production of moisture.
  2. Connect your humidifier to the hot water line, as this can increase humidity up to 30%.
  3. Check the setting of your humidistat to ensure it is set higher than current humidity levels in your home (when in doubt, turn it all the way to the right at maximum production).  If you don't know what your current humidity level is, use an instrument called a thermohygrometer to measure both heat and humidity levels in your home.  
  4. Calculate your humidity load (Gallons Per Day - GPD) via our humidity calculator. Check to see that your humidifier model is designed to produce the amount of moisture (GPD) you need.

There is moisture inside my duct.

Possible Solutions:
  1. Re-set your humidistat.
  2. The air flow through the duct may be too low, so you may need to increase air flow.
  3. Turn down your humidistat (decrease humidity).  Wait to see if this helps.
  4. The humidifier may be active when the fan in the duct is off.  Check the connection of the device controlling the humidifier to the ventilation in the duct (the flow switch or differential pressure switch).
  5. If none of these solves this problem, contact your contractor.  He/she may need to check the wiring, installation and your humidistat to ensure correct installation or determine if there is a faulty part. If you do not know who the contractor is, find one here.

My water continues to flow even if my system is off.

Water flow when the furnace or humidifier is off indicates a wiring fault or valve failure. To check the problem, perform the following when the furnace is on.
  1. There may be a worn seat in the electric valve.  
    Use a manufacturer's valve wrench to disassemble valve for inspection. If valve leaks at seat, replace the valve.
  2. Inspect the valve sleeve and plunger for excessive dirt.  Clean if necessary.
  3. The valve may be installed incorrectly.  Water must flow in the direction of arrow, or as described by "in and out" shown on valve.
  4. Turn the humidistat to "off". If the flow stops, this is good. No fault is indicated.  If water continues to flow into the humidifier, disconnect the wires at the solenoid valve.
    • With the wires disconnected, if water continues to flow, the solenoid valve has failed. Replace the solenoid valve.
    • With the wires disconnected, if water stops, the humidistat has failed or the unit is wired incorrectly.
If water stops in both cases above, turn the furnace off. Water flow should stop. If it does not, the humidifier is wired incorrectly.  Contact your local contractor for help.


Water is leaking slightly at the bottom of my steam humidifier. Why?

This often occurs after a steam cylinder replacement. We generally find that when a customer lifts the old canister out of the unit, the red O-ring (also called a gasket) and plastic bushing lift out as well (see photo below).

Humidifiers - General Filters, Inc. - Steam_Bushing_and_O_Ring_4Humidifiers - General Filters, Inc. - Steam_Bushing_and_O_Ring__3

Customers have reported not realizing these pieces fell out, or they didn't know they needed them, or they threw the pieces away because they thought the they were automatically part of the new cylinder.  DO NOT throw these pieces away!

Humidifiers - General Filters, Inc. - Steam_Unit_Depicting_Bushing_Location

Together, the plastic bushing and red O-ring assure a tight seal for the new cylinder-to-pump connection, so be sure to carefully replace these before installing the new cylinder. (A new O-ring will accompany your replacement cylinder.) If you have already lost them or discarded them, call our offices at (866) 476-5101 to order replacement pieces. Do not run your humidifier until these pieces are installed.

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