Aprilaire400 Humidifier Bypass

This Aprilaire 400 arrived quickly and with no damage. One small 1/4 inch ferrule was missing but was easily acquired from a hardware store. The price was very competitive compared to other sources. Installation was not for the faint of heart but it is now installed and works perfectly.

The AprilAire 400 installed on a Heil HVAC system with forced air / ACFull disclosure: I'm not an HVAC installer, plumber, or electrician (I'm not even a mechanic) and have never attempted any similar project prior to this one. I was not given this product in exchange for a review. I understand that does happen. Please read the entire text and especially the NOTES AT THE BOTTOM.Once I fully researched the installation procedure by watching a number of YouTube videos and perusing the manufacturer's owner's manual and installation booklet for the Model 60 controller and the main unit, I decided I would order this humidifier to replace another, different brand, unit that was not working.WARNING: Ensure the power is OFF for the HVAC circuit prior to attempting the installation. Allow yourself ample time to complete this project, so if it an extremely cold day, it's probably not a good time to try pulling off this project, since you won't be able to heat your home during this time. The entire project took me about 5 hours, give or take. Some of which was discovering I needed additional hardware, e.g. new bypass duct, wire nuts, wire ties, etc..., so trips to the store added more time to it.I had to pick up a few things to do the tasks necessary to complete the installation. I purchased a metal cutting jigsaw blade to make the existing cut larger for the AprilAire 400, 100ft of 2-conductor solid 20 gauge wire (tried to find stranded, but wasn't able to in a reasonable gauge and length), a small tube of silicon sealant to seal up the hole I was to drill through to the outside for the temperature sensor, a drill bit designed for drilling through masonry/brick (ensure it is long enough!), a special hole cutting bit for metal (for the control sensor that's mounted on the return duct) - it was basically a round 3/4" piece, as required, with a main bit in the center to keep the drilling centered and accurate), some wire ties for wire management, a bag of wire nuts appropriate for the wire sizes being combined, a 6' length of expandable and flexible duct work for the bypass (from return duct to humidifier) - the existing piece was slightly too short to reach the new humidifier, so I opted to just replace it with something easier to work with.), and a roll of foil type duct tape (doesn't become brittle like regular duct tape).I already had:1. Copper tubing for the water line2. Wire stripper/cutter3. Black & Decker 9.6V cordless drill/screwdriver4. Copper tubing cutter (a device that is put around the tube and spun till it cuts it)5. Existing 24V connection with a sufficient amp rating (from previous humidifier)6. Sheet metal shears to cut where I could not use the jigsaw7. A wood drilling bit (to drill through the floor a hole to run the outdoor temperature sensor)8. Sheet metal screws from old humidifier mounting9. Longer (3/4") sheet metal screws for mounting the control sensor to the supply duct10. A jigsaw11. Various other tools, i.e. wrenches and screwdrivers.The most challenging parts of the installation were feeding the outside temperature sensor through the outside wall and cutting the supply duct behind where the humidifier mounts. I did not have any existing holes to use on that side of the house. The other sides were either on the south or just too difficult to get to from the basement. The second most tedious part was cutting the existing humidifier's duct hole larger. I used the jigsaw where I could, but had to finish up quite a bit with sheet metal shears.Mounting of the saddle valve seemed almost too easy. I have a combo of mostly PVC and some copper piping. I opted to saddle on a hot water pipe just up from my water heater (about 4ft away), which is right next to the furnace anyway.I taped over the removed humidifier's screw holes to prevent air leakage. The old unit was shorter and wider than the new unit and had a much smaller duct opening behind it.A high level approach:1. Run the outside temperature sensor2. Disconnect power to HVAC system3. Remove existing humidifier, if applies4. Drill 3/4" hole in return duct to mount control sensor (adhering to distance requirements in booklet)5. Run wires where they need to go per the control sensor instruction booklet6. Tape up template on supply duct, being sure it is level,(install instruction page) and draw around it for where you need to cut and then cut it out.7. Mount humidifier into new supply duct hole8. Mount saddle valve. The instructions did not say to turn off the water supply for copper or PVC, but I did anyway.9. Run copper tubing to humidifier's solenoid valve. Tighten per instructions.10. Run copper tubing line to saddle valve and giving enough to work with, cut the tubing to length11. Mount the copper tubing to the saddle valve12. Wire the 24V as described in the manual. Be very careful with this part, it was a bit confusing to me at first. Look at the drawing to make better sense of it.13. Connect your 1/2 inch inner diameter (I.D.) tubing to a drain or a condensation pump14. Restore water flow - checking for leaks (check again after a while - often takes a while to develop some leaks, if they are small)15. Restore power to the HVAC system16. Test the unit per the instructions to ensure proper operationNotes:I experienced a very slight leak at the saddle valve. It was easy to fix by tightening everything, except the saddle mount itself. Be sure not to over tighten the actual mount, as it could crush the pipe. Just make sure it is tight and secure. It should NOT easily slide if mounted well. The leak I experienced was at the actual compression connection of the tubing.I had to use the sheet metal shears when cutting parts of the rectangle behind the humidifier mostly because the cooling coil sitting behind this area had some coolant tubing that was too close to the area being cut. Had I used the jigsaw entirely, I would have damaged the cooling tubes. Be careful with this.This review may contain errors, for which I apologize for in advance and I assume no responsibility or liability. Be sure to read your instructions thoroughly. It is recommended that a qualified HVAC installer handle the installation. My order of events reflect my actual order of events, but some things could likely be done in a different order. When in doubt, have a professional do it.

Takes a fair amount of time to install. I put the outdoor temperature sensor in the fresh air inlet pipe for my HE furnace. I used a tee, some fittings and a valve for the water supply rather than the supplied saddle valve which is not reliable. The light aluminum foil bypass hose is very delicate and susceptible to damage. I used a sheet metal elbow and some much heavier flex hose. Works well with the temperature probe to prevent windows from having condensation when it is very cold outside.

I’m impressed by those who say they installed this in a couple hours after spending $30 at the hardware store on supporting supplies. I’m an advanced DIYer and I think I spent around $300 on various things: pvc tubing, copper tubing, valve, condensate pump, etc etc and I’m probably about 8 hours into it overall. But this baby is in and running for a few weeks.4000 sf house with the furnace this is installed on conditioning around 3000 of the square feet. I’m running this unit manually and getting about a 10% increase on my home’s relative humidity, from 30% to around 40% which is a huge improvement in comfort- from a dry eye and temperature tolerance standpoint. 72 is now perfectly acceptable to everyone whereas at lower humidity we really needed the house at 74.I’m operating this on a variable speed Trane furnace. We operate the fan on low (50% speed) 24-7 which helps the function of the humidifier. I did not use a hot water line to supply the unit and don’t think I will need to.My digital controller was broken out of the box and I am running the unit manually. It’s supplied with water continuously and as the water dries up a level switch fires the solenoid valve and fresh water flows into the unit automatically. Then the cup at the bottom fills again and the level switch closes the solenoid and water flow. There’s no wasted water to the drain which is super cool.Since we use the furnace fan 24-7, I didn’t need to wire the electric controller into the furnace. This is great because I won’t void my Trane warranty this way. They essentially operate independent of each other but if the furnace was shut off the level switch on the humidifier would shut the water to the humidifier down. If that doesn’t work, then the water will overflow into a drain, in my case a condensate pump. I plan to use a separate humidistat to create a feedback loop to prevent the humidifier from making the air too humid. But I don’t think there’s much risk of that in our area, I’m just being thorough and fastidious.The only thing to add in my case is that I can get more humidification by running my furnace fan speed higher. This would increase airflow through the humidifier pad and shift the improvement from a 10% increase to something higher. But since we’re getting what we need on fan speed low, no reason to spend the extra electricity

Sur les photos, il me semblait parfait pour mon système central mais la sortie n’est pas du bon côté, pas comme sur les photos que je voyais. Je vous le retourne dans les jours qui suivent