How to add table salt to the Fill Cup of an Aprilaire 800 Steam Humidifier

My Aprilaire 800 has worked well since installation in 2012. I always replace the cannister myself at the start of the heating season, usually Nov. or Dec. A plumber replaced my hot water heater last June and changed the plumbing and valve that supplies water to the Aprilaire. He verified the unit came on, but since no humidity was needed until cold weather, the unit stayed dormant until December, when I installed a new cannister and turned it on as usual. From that point, the unit has worked for a few days, then stopped humidifying and the service light flashes red. I turn the unit off, turn the circuit breaker off and on, restart the unit per manual procedure, and it works for a few more days. Then the service light flashes red and the cycle repeats. Since the cannister is new, the manual suggests adding 1/10 teaspoon table salt to the "Fill Cup," but I can't see how to access or open the Fill Cup to add the salt. The cup appears to be inverted, so even if I disconnect the supply tubing, won't the salt just fall back out into the tubing when I place the cup back in position? Any suggestions? Any possible connection between the plumber's changes and this problem? Thanks for any advice.

 

Welcome to the forums.

I have limited knowledge of this unit. I'm guessing yours is running on 120v as units running on 240v don't appear to get this problem.

From Aprilaire tech....
Dissolve one teaspoon of salt into one cup of hot water. Add to the fill cup in 1/4 cup increments until unit operates properly. Yellow steam light will clear after first fill valve cycle at nominal amperage operation. Do not over salt. System will drain and refill with clean water due to over current fault.

The top of the fill cup should be removable.

 

Ah, thank you very much! Yes, it's on 120V. Will try this and post the result.

 

It took awhile, but I'm tentatively declaring success, so thanks PJmax. First I tried adding 1/4 cup of the hot salted water with the power off, but after startup and the usual 3-4 days, the service light started flashing red again. Today, I kept the unit on while I repeated, 1/4 cup at a time as advised, waiting one steam cycle between each addition. After the full cup had been added, there was a brief discharge, then the steam light came on green again and the service light went out. Time will tell, but I think it's fixed. Thanks again!

 

Hopefully..... problem solved.

 

I have had the same problem and the teaspoon of salt in a cup of water works. Thank you!

 

So I had the same issue with the yellow light and flashing red service light even though I changed the canister about 2 weeks ago. I just put the saltwater and the yellow light went away. I'm hoping this helps solve the problem. My Humidifier is set to 40 but I have a small thermometer that measures Humidity and it is showing at 20. Big difference

 

Set to 40 what...... 40% humidity ?
The humidity will only increase if the humidifier is running and the blower is on.

 

After calling Aprilaire and talking with sercise they said not to add salt when I mentioned that to them.

What he told me is that there's something in the system that needs to be reset when replacing the canister and the way to do it is turn off the power to the unit for at least five minutes.

Anyway, after dealing with the blinking red light all the time turning the power off like that seems like it reset whatever it is because I haven't had any issues with it since.

Mike