Hm3500 only one tank empties I have traded caps and it still empties one tank long before the other I am wondering if it might be a level problem

Tanks are no longer available. Search for used units on your local craigslist.com. This model was previously made by Holmes and tanks were the same on HM3500, HM3501. Search "Holmes humidifier" then search "sunbeam humidifier" on your local craigslist.org

most bigger towns will have one or two show up. Keep an eye out. People who move to a house (or install) a whole house humidifier sell their old units. We have two of the exact model and I bought a new in box 3501 from a Craigslist posting in September 2013!

http://safemanuals.com/user-guide-instructions-owner-manual/HOLMES/HM3500-_E

http://www.holmesproducts.com/Index.aspx

Welcome to Fixya!

• Ensure that the water tank cap is secured properly to water tank.
• 
  Empty out water in water basin. Place filled water tank on to empty water basin.
• 
  Clean Water Level Sensor.

Hope this helps!

Hi there,

The tank may be full. Your dehumidifier has a safety device that turns off the dehumidifier when the water tank is full. Usually the tank itself either presses against a switch or there's a device connected to the tank that triggers a switch when the tank is in place and full.
If you've emptied the tank and the unit doesn't run, inspect the place where the tank rests to see if there's a switch or mechanism that's not being activated. You may be able to turn it on with a simple flick of your finger.

Post comments  for more help or information .........

Good Luck!!

Thanks

Mine also cracked along the seam several years ago. I sealed the crack using two-part waterproof plastic epoxy (found at any hardware store.) Not really pretty to look at, but it hasn't leaked since!

Hi, you can download the PDF manual from here

http://safemanuals.com/user-guide-instructions-owner-manual/HOLMES/HM3500-_E

Located My Manual:
Hope this helps!

1. Remove tank from base. Turn upside down and unscrew filling cap. Fill tank with clean, cool, distilled, or tap water. Water temp should NEVER be too hot or too cold. Return tank to base and let sit for a few minutes. Be sure the filling cap of the tank is tightened firmly.

2. Plug power cord into a 110-120V AC wall outlet only. Turn power switch to "on" position. Power light will illuminate. Turn mist nozzle until desired level is being released. Aim nozzle away from furniture and walls.

3. Always turn humidifier off when water runs* out. Unit will continue to operate when tank is empty.
*Humidifier will run up to 12 hrs on low; 6 hrs on high.

DO NOT LET WATER SIT IN TANK FOR LONG. THIS CAN ENCOURAGE BACTERIAL GROWTH.
Place unit on level surface away from direct sunlight.
DO NOT ADD MEDICATION OF ANY TYPE INTO THE NOZZLE, BASE, OR WATER TANK.
ALWAYS LEAVE ROOM DOOR PARTLY OPEN. DO NOT MOVE, TILT, OR EMPTY WHILE OPERATING.

Mild bleach and water solution for cleaning, never detergent.
Clean every 3rd day during use. Clean after long storage
Humidity varies from room to room. Aim for 30 - 50% relative humidity. If windows/ walls fog or frost, reduce mist intensity. If room too humid, ventilate by opening door or window; adjust mist intensity.

I had the same problem if you dissasemble the unit you will probably find a capacitor between two blue wires has blown out