Background
I got the Ultenic H8 humidifier last winter on Amazon. A couple month later it displayed the “EF” error on boot. According to the user manual, “EF” error means that there is too much water in the basin. Emptying and refilling the humidifier fixed the issue. We put the unit away for the summer and just set it back up again earlier this month. Within a weeks, we started seeing the same error, but refilling the unit would not resolve the issue this time.
This same humidifier is also rebranded and sold as a Crane TOP FILL EE-6913. Doing a google search I saw several complains about the “EF” error, but no remedies.
Root Cause
The “EF” error means the basin has too much water, not the tank. The basin is the area under the tank. The amount of water dispensed into the basin is controlled by a seesaw-like buoy on the bottom of the basin. As the basin fills up, the buoy floats to the top and prevents additional water from entering the tank, and a problem with this mechanism is causing the “EF” error. I quickly noticed that there was water inside the plastic buoy, which is not expected! Upon close inspection I noticed that there are small cracks around the edges which would allow the water to very slowly seep in preventing it from floating.
The Fix
We first need to get the water out and patch up the cracks. I drilled a hole in the side of the buoy and drained all the water out. It seems that the water has been in there since last season and mold/bacteria started to spread. I made sure the completely rinse out the inside with soapy water and followed by cleaning out with 99% IPA to make sure any mold/bacteria which was inside no was no longer present.
After drying, I was ready to reseal. First I sanded around the edges a bit to ensure the glue can get a good grip on the plastic and a leak doesn’t re-occur. I then cleaned it with 99% IPA to get any oils off from touching it. You can use superglue or a hot glue gun, but I like to use epoxy resin as it has a stronger bond; I used J-B Weld 8265S. You mix the two tubes, and then have 30 minutes to apply the mixture.
Final words
After letting the epoxy dry for 24 hours, I reinstall the buoy back into the humidifier and now it’s been working without any issues.
Update – Issue Returns!!
It’s been a couple of months, and the humidifier was working fine, but the EF error started occurring again this week. After a prolonged investigation, the solution was quite simple this time. A small flapper valve controls water flow to the bottom basin. This valve is spring-loaded. The spring has lost its tension, so the valve lets more water in than it should.
The spring is accessed by unscrewing the filter and pulling off the rubber seal. Once the spring is out, stretch it out a half a cm or so. With this modification, the valve will be much more robust at stopping the water at the correct level, preventing overflow and the EF error.
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