Features:

  • This genuine Aprilaire humidifier replacement part was designed to optimize the performance of your Aprilaire Whole House Humidifier Model: 400, 400M, 500, 500M, 600, 600M, 558, 550A, 550, 568, 560A, 560, 700, 700M, 768, 760A, 760
  • The Aprilaire 4040 Solenoid Valve controls the amount of water that enters your Aprilaire Whole House Humidifier, ensuring that the right amount of humidity is delivered throughtout your home
  • The Aprilaire 4040 Solenoid Valve is part of the core of your Aprilaire Whole House Humidifier, making it possible to maintain proper humidity levels throughout your home
  • The Aprilaire 4040 Solenoid Valve, 24 Volt is compatible with Aprilaire Whole House Humidifier Model: 400, 400M, 500, 500M, 600, 600M, 558, 550A, 550, 568, 560A, 560, 700, 700M, 768, 760A, 760
  • HUMIDITY FOR HEALTH Aprilaire Humidifiers can help you maintain optimal humidity in your home of 35% – 45% which has been shown to reduce the incidence of respiratory infections and symptoms related to allergies and asthma
OEM Aprilaire solenoid - real deal

This is a OEM Aprilaire solenoid. It is cheaper than on the Aprilaire site. I had an Aprilaire model 700 installed in August 2015, so this part was still under the 5 year warranty. Aprilaire will only honor the warranty if you go through the installer of the product so they told me when I called. I found this not satisfactory as it is a simple replacement and I certainly didn’t wish to pay the installer who warrantees the labor for one year $125 to come and install this part. This requirement to have the installer replace the part in effect makes the warranty worthless!. It took about 10 minutes to install the new soliniod and it works well. There is a good video on the Aprilaire site that shows how to test to see if the solenoid is the problem and it helped me. You are supposed to clean the inlet filter once a year and the pin hole on the output side. The installer never mentioned either of these things. Delivery of this product was two days - great service!

Read before declaring unit defective

My humidifier stopped humidifying and I called my installer to do a diagnostic. He confirmed I needed a new solenoid and it would be $200 to install on top of the $50 tech visit. That’s the cost of a new humidifier! Bought this new solenoid and installed it in 10 mins. Super easy and I’m not a handy guy. Unscrew old, remove water line connections and wire nuts, then install new. Always make sure water line is turned off to the humidifier and everything powered off. Anyway, fire it up and I still had the same issue! After some poking around, I decided to remove the orifice that connects to the flexible water tube that drips into the filter. Turned it on and voila, it worked. I know I needed the orifice to reduce the water flow for it to work properly so I checked the orifice and held it up to a light. I saw the tiny hole was clogged with a tiny bit of calcium. I used a needle and poked it out and ran under warm water. Reinstalled the orifice and problem resolved. For those who have said they received a defective solenoid, make sure you check the orifice. I am using the new solenoid and my old one is in storage in case this one ever fails.

Our service guy wanted $277 to install this! I spent 10% of that and installed it myself in about fifteen minutes!

Our humidifier hadn't worked for years and so when we had recent HVAC service, the guy tested it and said our solenoid valve had gone bad. My job about dropped when he gave me a quote of $277 to replace it! This was more than we'd paid for the entire humidifier! Thanks to Amazon and some helpful videos on YouTube, this was an easy repair and took me about 15 minutes. Now our humidifier cranks out the moisture and I can actually hear the water kick in when the furnace turns on so I know this is working. If you need to replace this part and you're even remotely mechanically inclined, I highly recommend buying this part and doing it yourself and saving a lot of money!

15 minutes saved us $250

Our whole house humidifier went out last week and after some self diagnosing I was pretty sure it was the solenoid. We called out our HVAC company who wanted $280 to replace it! Shocked I popped on Amazon and found this for $30. Ordered it and had it here next day. Took a total of 15 minutes to install and BAM we have humidity again! We like our HVAC company and I would have just let them do the work if they quoted something reasonable but I knew it was gonna be a quick install and $280 was just outrageous. Installation is dead simple: take the 2 screws out, disconnect the 2 water lines, unscrew 2 wire nuts— and reverse the process with the new one. Take your significant other out to a nice meal with some of the $$$ you saved :D

Roll up your sleeves and get it done!

I decided I would return the new Aprilaire humidifier I ordered and go this route instead. I knew my old Aprilaire 440 was a dinosaur, and that the solenoid was shot. But, after realizing that the sheet metal cut-out was much larger than the unit I would replace it with, I decided to fix instead of replace. This solenoid fit perfectly, and was a snap to rewire. Once I got the leaking fittings squared away, it has worked without incident. Highly recommended, and not too difficult for the average weekend warrior.

Saved me money from a contractor.

Our thermostat was showing the inside humidity at about 20%. Two contractors offered to "diagnose my problem" for $80-90, but warned a fix may cost as much as $500. I thought this was worth $50 to try before spending any of that money, and was successful. It was rewarding to see water flowing into the humidifier again and the humidity started rising that same evening. Now we're back into a normal range 30-40%. Has been working for several weeks now after a fairly easy install. I watched several youtube videos and the troubleshooting guides on the Aprilaire website for my Aprilaire 600. I recommend watching their videos before spending big money on a contractor.

Perfect match

We have well water where we live so our plumbing is prone to mineral deposits. I found that one solenoid was partially clogged and the other was seized shut. For the price I opted to replace both instead of trying to clean out the old ones, even ordered a spare to have handy. I only wish that these came as a kit with the inlet filters and the outlet nozzle. Installed on Aprilaire model #500. I could not find a difference between this and the one it replaced, as long as it works I dont really care either. To test the old ones I jumped the 24v supply on the humidistat, heard it try but not a drop came out.

Compatible with the Aprilaire 4040 part.

We purchased an Aprilaire 500 and during setup, my husband didn't realize that he was hooking it up to the wrong Voltage (excuse for, he forgot to use the 24v converter that came with the humidifier) for the solenoid. This caused the solendoid to dry a few seconds after it started up . While this solendoid was larger in appearance than the original, it did indeed work. And, after using the converter this time, our humidifier is now running great!

Solved slow water flow problem/ overheated solenoid valve

Excellent exact replacement for OEM. A few turns of a wrench, two wire nuts; and voila. Full water flow. Should have replaced this at year 2. Did a full replacement of solenoid valve, water panel, tubing. Maximum flow and system works like new. (because I've pretty much replaced every part.) We had a water heater fail, and there must have been rust that gummed up the solenoid filter and gotten into the valve. 1 aprilair humidifier maintenance kit and this valve cleared up the problem.

Direct and exact OEM replacement and no worry (+/-) on the wiring, follow the existing to replace.

Exact replacement for my Aprilaire 700 humidifier OEM solenoid, can not be any more straight forward and it comes with the inline filter, however, you do need to reuse your existing orifice. Compression nut on the inlet side is also included; but I used my existing fitting/nut.

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