20 Most Recent Holmes Products HM5250-UC Humidifier Questions & Answers

According to Holmes, one of the causes of the Reset light staying on is scale buildup on the heating element.

Remove Scale: Allow to cool before maintenance.
1. Repeat steps 1-5 in the Daily Maintenance section.
2. Clean the base by partially filling the base with one
8-oz cup of undiluted white vinegar. Let solution stand
20 minutes, cleaning all interior surfaces with a soft
brush. Dampen a cloth with undiluted white vinegar
and wipe out entire base to remove scale.
3. Rinse with clean warm water to remove scale and the
white vinegar solution before beginning to disinfect
the tank.
4. Wipe the heating element clean with a soft cloth after
it has had chance to cool.

If the scale has really built up it might take longer than 20 mins for the vinegar to get rid of it and you might need to refresh with new vinegar.

Your Manual can be found at this link:
http://www.holmesproducts.com/Manuals/Holmes/HM5250-UC_English.pdf

Good Luck.

You really have an mineral problem. I have pretty much same here. I only use bottle water that comes in gallon size from grocery. Ot is the only way I have found other than constand cleaners or a water softener. Good luck

Go to http://www.holmesproducts.com/service-%26-support/product-support/instruction-manuals/humidifiers/humidifiers-manual.html and see if one of those listed will help you. The specific model HMS 250 seems to be out of print, but the current ones may help you with what you need to know. If not, contact them at https://www.holmesproducts.com/contactus?cid=contact-us and see if they will email you the correct one.

If the water has been sitting in the reservoir for days without use, it may develop a film on the ultrasonic element which inhibits the creation of the mist to come out the top of your humidifier. I would lift off the tank and empty the reservoir. Then VERY GENTLY with a piece of paper towel, wipe the ultrasonic element (looks like a disk the size of a quarter at the bottom of the reservoir) to clean off any film. Then replace the tank and let the reservoir fill up the tank and try it again. Good luck thebqe