Holmes hm500 manual - Holmes Products HM500-UC 1 Gallon Humidifier

Page 2 of the manual has it is words.

https://manualzz.com/doc/52322507/holmes-hm7808-cool-mist-humidifier-owner-manual

https://www.google.com/search?q=change+filter+on+Holmes+HM7808

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If you are trying to descale it of all the mineral build up. The easiest way is to mix a 50/50 1 gallon solution of Distilled White Vinegar and Bottled Distilled Water and pour it in the empty tank. Allow it to sit for a couple of hours (Longer if it's really scaled) . Then turn it ON and run it, until the tank is half empty. Then empty the remaining solution and fill the tank with Bottled Distilled Water and run until it's empty. In the future, it's better to use Bottled Distilled Water, rather than tap water.

Hope this helped you and thanks for choosing FixYa.

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

Thatis a safety feature designed to avoid overheating due to being empty.
You need to reset it.
Unplug it for a few minutes, and then set it to reset, after plugging it in. It should be working after a few minutes.

If you can see the mist, then, it is working. The outlet
port of your humidifier could be closed/stucked up/clogged. Please check this the outlet port.

i would try cleaning the coils for the heat portion. if they are to scally that could be one reason why it's not making any mist. but if it looks pretty clean or if you have cleaned it and it's still not making any mist then it's something internal. now if your under warranty still that's a good thing. you can always call the manufacturer and they can replace theunit for you under warranty . if you have any other questions please let me know.

unfortunately on a cool mist unit the mist shouldn't show up. on most units that's what it does. the warm mist units show the mist.. the best way to tell is if you put your hand over the spout that the mist is suppose to come out of for about 2 minutes and you pull it away and it feel clammy then it's working. if your hand is still dry please let me know and i'll see what else i can do for you.

I have a manual for the Holmes Model HM5601. If you contact me I can make a copy & mail
it to you.
My email is [email protected]
Dave

unfortunately running the unit for too long will permanently ruin the unit. there isn't really a way to fix it. i do deeply apologize for that. so unfortunately you might have to replace the unit.