My yellow light is still blinking on my Aprilaire Model 600.

Consumer question:

Yellow light still blinking…I have a model 600 installed by a licensed contractor a year ago and it has a control unit with a digital readout but no manual switch nor a test -reset setting on the dial. It has three lights to the right of the readout. The yellow one is lit indicating to change the A-35 pad which I did. How do I reset this type of control unit?

Aprilaires’ response:

Thank you for contacting us regarding your model 600. To reset the change water panel light, put the control in the test/reset position while the furnace is on and the HVAC fan is running. After the control runs in the test/reset position for 1 minute, put the control knob back to the previous setting. This will reset the internal timer for the light and turn it off.

The words test/reset can be a little hard to read but they are located past the setting of 7. The letters are the same color as the plastic but are raised and you can feel them with your fingertip.

Please view the attached owners manual for the model 600. This procedure is explained on page 3

If you have any further questions regarding this or any of our products, please feel free to contact our customer service department at your earliest convenience.

13 thoughts on “My yellow light is still blinking on my Aprilaire Model 600.

  1. dennis westfall

    I have replaced the filter-turned to test-reset while the furnace s running and the green light comes on and water flows but the yellow change flter lght never quits blnking!! Now what!!!

  2. Michael Grinnell

    This was very helpful. Dennis, the instructions above worked. Not sure why Aprilaire made the control like this because it is almost impossible to read ‘test’. It is some way past 7 and it almost seems like you are going to break it but it will go to test and reset the light.


    I just had my april air 600 with automatic control installed oct 2013 now 2 1/2 months latter the yellow indicator light is coming on saying my pad needs replacement? Is this normal ?

  4. brad

    Thank you for your question regarding the change water panel light on the humidifier control for your model 600 Aprilaire humidifier. The change water panel light typically is displayed after 600 hours of runtime which would be 25 days of operating 24/7. While we don’t believe your humidifier ran 24/7, mid-October until now is approximately 75 days. You may want to inspect the water panel to see how saturated with mineral deposits it is. If you can see light through the panel you should be able to get a little more life out of it. Otherwise, if it is full of deposits or the humidity in your home starts to drop, you will need to replace the panel. Anytime you replace the water panel simply reset the change water panel light by placing the dial into the test/reset position for 5-10 seconds and then return the dial to its’ previous position. The light should then go out.

    Thank you for giving us the opportunity to be of assistance.

  5. Wendy

    My water panel also indicates it needs to be changed after just 4 months. It is saturated with mineral deposits, to the point that white dust is covering the unit and spilling out to the floor. Is there anything that I can do about this?

  6. Brett

    Thank you for contacting us with regards to your Model 600 Humidifier. The change water panel light is a reminder light on a 600-hour timer. After that time has elapsed, it will signal that it’s time to change, or at least check, your water panel. In your case, we would recommend changing the water panel and cleaning the plastic frame to remove any residue. Reset the change water panel light by turning the control knob to the Test/Reset position until the green Humidifier On light starts flashing. When that happens, the change water panel is reset and its light will turn off. Turn the control knob back to its previous position.
    Please let us know if we can be of further assistance.

  7. JH

    Methods above to Reset Panel Timer will not work unless the ‘G’ wire terminal is energized, at least temporarily. Some newer HVAC systems run fan continuously, so ‘G’ may not always be wired for these installations because you shouldn’t run the humidifier continuously, unless you are calling for heat.

  8. Iris Moreano

    AprilAire 600 humidifier is running perfect but green light is off when furnance is running. is that normal? I did the reset test and after I did that the light it’s been off since. what should I do?
    Thank you!

    1. aprilaireadmin

      Hello Iris,

      Thank you for contacting Aprilaire.

      The #60 control with the digital display offers three lights. The red light may come on where there is an error, or need to contact a technician. The yellow light comes on when it is time to change the water panel. The green light comes on when the humidifier is actively making humidity.

      Even though the furnace needs to be on (either making a heat call, or just a fan call ) to make humidity, just because the furnace is on does not necessarily mean that the humidifier also is on. Perhaps the furnace is on heating the home, but the level of humidity is at or above the level selected on the humidistat controller. Then the green light would not be on.

      Feel free to phone us Monday through Friday from 7:00 am to 5:00 pm central time to discuss. 1-800-334-6011.


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