Aprilaire 700M Whole-House Humidifier with Manual Control

OK, this is exact same as the automatic except it has the manual humidistat. I was a bit nervous about installing this because of how little room to install this. There is literally 1/2" between the wall and this now. But works amazing! Straight forward installation. Installed on the supply plenum. One thing, don't use the saddlevalve they give you. Go buy a sharkbite valve. Super easy to install with no soldering required. List of supplies used. 1. Metal tape (duct tape for the plenum but made of metal) 2. Tin snipe. (To cut the plenum) 3. 3/4" sheet metal drill bit (titanium or better) 4. Sharkbite valve (connect to water line. Just push pipe in both sides((1/2" osd)) 5. Sharkbite 1/2" to 1/4" on/off valve 6. 1/4" osd foggy plastic hose (connects to the water inlet on humidifier) 7. 1/2" clear tube (for the drainage tube on humidifier to drai ) 8. 18x2 thermostat wire, wire nuts, and plastic tube to hide wires. 9. 1/2" copper tube. Maybe need only 3"-5" (extends the sharkbite valve) 10. 20' outdoor extension drop cord (only if you don't have plug near supply plenum) 11. Level 12. Electric drill 13. Yellow handle tin snips (yellow means cuts strait lines or curved) 14. #8 self tapping sheet metal screws. 1", and only 4-6 is needed. 15. Pipe cutter 16. 13mm open socket wrench Shut off breaker to furnace. Do not install before you do this. So, the toughest part on the install was cutting the plenum. I didn't have enough room for the drill to drill hole, but was creative and got one made. The instructions are the template for the humidifier base. Used a level and made sure it was on level. I chose to use the supply plenum to install so I wouldn't need to use hot water. Save a few gallons of water daily. After the square hole was cut, I used a hammer and pliers to make sure the edges were even. Then mounted the base, and screwed it in. Next, used the metal duct tape (do not use regular tape, must be the metal kind) to tape around the base. Take your time and make it look good. Next, wiring. The bottom of the base has two brown wires. Using the 18x2 thermostat wires, connect one brown wire to the common circuit on the furnace circuit. Should be labeled C. Next, connect the other wire to the W (24v aux). Connect that wire to one terminal on the humidistat. First mount the humidistat where you want it. After the the power wire is connected to the humidistat, add another wire to the other post in the humidistat. Doesn't matter which one you use. Take that wire and connect it to the other brown wire on the base of the humidifier. Next is the water. If you have a water softener, you will be using the copper line going from there to the water heater. Shut off the main valve and grab a small bucket (water will drain from the line) and place under where you want to install the sharkbite adaptor. Use a black marker and mark the pipe. Then measure 1" both left and right. This is where you want to make your cut. Cut the pipe in both spots so you have a 2" space between ends. Slide the sharkbite adaptor in between and press the adaptor hard in each side. It will lock in to place. Cut a 3"-5" piece of spare copper pipe and push in the middle of the adaptor. Then attach the 1/2" to 1/4" sharkbite valve. Push it hard and it snaps in. Take off the 1/4" but and the copper coupling inside. Slide the foggy 1/4" tube through the but and then the coupling and in to the valve. Using a #13 wrench, tighten the but down as much as you can without breaking it. Connect the other side of the tube to the bottom of the humidifier base. Using the same method of through the but and coupling, then tighten down a lot. Otherwise this will leak. Next connect the 1/2" drain line. Run it from the bottom of the humidifier base to your drain near the water heater or softener. If there isn't one, you will need to buy a pump and attach it to there and pump it out of the house or to a drain. Last, use the extension cord, connect from outlet to plug on the humidifier. Use the black tube to conseal the wires if you want. Turn on the water to make sure no leaks. If there are some at the valve and base of humidifier, tighten those nuts down. It will stop leaking. May seem like you will break the sylanoid on the base, but it won't. Turn on the furnace breaker, set the heat to high to you can monitor the humidifier. It should be working fine. Alternative install. Use the transformer and connect to the HUM spot on the circuit board and the other to Neutral, the the humidistat to one of the back side and other goes direct to the brown wire on the base of humidifier. I am not a HVAC tech. So if you have questions I can't really help. But installing yourself will take 3-5 hours depending on trips to the hardware store. It will also save you between $350-$500. The total cost of the parts were right around $100. But because I didn't have the drill bit, the pipe cutter, yellow tin snips, metal tape, extension cord, or tubing. If you have those, the sharkbite adaptors will be around $25. So far we have felt an immediate impact on the air quality. Well worth the price.

Purchased an open box unit at a discount and it came in the original box. The Aprilaire 700M replaced an older 760 model that fell off the furnace from the plastic getting brittle after many years. It fit the same cutout as the 760 unit. I had to figure out the wiring with the Model 50 Current Sensing Relay. Got it figured out after reading these step by step instructions. Step 1: Wire the 24V transformer and relay Connect one lead from the Model 50 relay to one of the 24V output terminals on the transformer. Connect the other lead from the Model 50 relay to the 24V lead from the humidifier. Step 2: Connect the humidistat and complete the circuit. Connect the remaining lead from the 24V transformer to the humidistat. Complete the circuit by connecting the remaining lead from the humidistat to the remaining lead from the humidifier. Hope this helps others with the wiring. It’s nice and quiet and provides humidity while the heat is running.

I got the Aprilaire 700M (manual) version because with a smart thermostat, you don't need an outdoor sensor to tell the temperature. The idea is that the relative humidity (RH) inside your house should decrease as the outside temperature also decreases. Otherwise you'll get condensation on the windows and other parts of your home, leading to frost, freezing, dry-rot in your attic or window sills, etc. The Ecobee4 knows the temperature at your location (via Wi-Fi connection) and has a "Frost Control" setting that will automatically adjust the home's humidity level accordingly; no need to use the manual humidistat and constantly change the humidity setting as temperatures change. I've attached a diagram of the exact wiring I used -- even the colors are the same. It took combining about 4 different diagrams that only told part of the story, a call to customer service, an email to an HVAC guy, and bit of trial and error (e.g. I had to learn not to use the HUM connection on my furnace because it's only charged when blowing heat) but my Aprilaire 700M and Ecobee4 now work PERFECTLY together! When I need humidity in my house, my thermostat will turn on the furnace fan and the humidifier to add humidity without heat... as well as with heat, if needed. IMPORTANT Instructions: 1) You DO NOT need to use/wire the humidistat control (dial-a-humidity level) because the Ecobee4 perfectly takes it's place (actually, it does a much better job). 2) You have to know that when you set up your humidifier with Ecobee, you have to tell it that it's a "steam" humidifier, NOT an evaporative one. This is not true, but it will allow the Ecobee to call for humidity even without heat blowing. 3) You need to purchase an extra relay to make the call for humidity without heat to work. Aprilaire recommends the Aprilaire 4851 relay. I'm not convinced there isn't a less expensive relay that will make this work, but I know the 4851 will work. 4) Take note that the G (green) wire needs to be disconnected from your furnace control board. This is according to the 4851 relay instructions. There are a few other oddities with the wiring too, so pay close attention. 5) Be sure to use 18-guage wire for 24 volt purposes (which is all this diagram shows) 6) I used the 2-wire setup for my Ecobee; there is a 1-wire installation, but I couldn't get it to work. 7) I did not need to use the transformer the Aprilaire 700M came with (because I didn't need extra 24v power). 8) When using no-heat with your humidifier, please note that Aprilaire recommends installing the humidifier on the hot-air service side of your furnace plenum, and to use hot water to flow into your 700M. This will allow the water to evaporate better. I'm going to add insulation around my 1/4" OD (outside-diameter) copper tubing (sold seperately needed for installation, with compression fasteners) to keep the water a little hotter. I used a SharkBite valve (Model # 24983A; 1/2" push-to-connect, 1/2" push-to-connect, and 1/4" compression fitting) to tap into my hot water line. The SharkBite fittings made it super easy to install onto my PEX hot water pipe. You may want to use something similar if you don't want to use the saddle valve the 700M came with (which I couldn't, nor did I want to run the risk). I had virtually no plumbing or electrical experience before doing this install, so you can do it too! I've attached a few other photos and the diagram that came with the 4851 relay, and the Ecobee4. I hope this helps! And enjoy your new perfectly comfortable home! p.s. Be sure to go to your electric company's website and look for a rebate on smart thermostats; the two main ones here in Colorado Springs both offer a $50 rebate!!! Free money.

I bought this to replace a failing Aprilaire 760. The actual humidifier works great...that is why I thought I'd buy this and do a straight swap. The company I bought this from gave wonderful service and I have no complaints about their service or price. Little did I know that Aprilaire bowed to the HVAC companies and made the installation much more challenging. They took out the built in 24v transformer and made it so this now needs to be rewired...totally different from what you may already have in place with your 760. If you are not handy at wiring, you will be forced to pay someone up to a couple hundred to wire this for you. Fortunately, my 760 had a 120v outlet wired to the furnace to kick on whenever the blower turned on. If you have this set-up, then all you need to do is splice the included transformer into the 120v power (use spade terminals) and wire your hot 24v output to the manual control (included), then connect the output from that to one of the brown wires on the humidifier. (The yellow wires should be connected together...these are for the water solenoid.) Then run a wire from the other brown wire (on the humidifier) to the 10v terminal on your transformer. This creates a power loop...from the transformer, to humidifier controller, to the humidifier, then back to the transformer. You must use the transformer for this. Plug the humidifier 120v cord into the same power source and you should be good to go. (The instructions are not all that clear on how simple this is...I think to intimidate people into not making this it a DIY project - granted, your wiring might be more complicated and may require a professional installer but my HVAC folks wanted $800 bucks...not even close to being reasonable.) The unit fits in the same space as your 760, and the water and drain hook-ups are the same.

This is a very good unit, relatively easy to install. I am not a technician, know very little knowledge about wiring. But I did some research on YouTube, reading reviews of previous owners, installed it all by myself. it works great. Here are some insights I would like to share: 1-This unit works with Nest (3rd gen) perfectly well, my furnace is Carrier Weather Maker 9200. Do buy the 700M model, you do not even need the manual control, (but need to have the 2 brown wires out from Humifier), neither the transformer that come with. 2- Install the unit itself is easy, just follow the instruction, buy a piece of copper pipe, and a 18 Gage security wire (the one I bought has 4 wires, 2 wires is enough). 3- Important is the wire connection. Make sure turn off all the power to your AC and Furnace before connecting any wire. I connected one of the 2 brown wires on the humidifier to the COM-common (has 24v) wire on the mother board in the furnace. The other brown wire connects to the * port in the Nest Control. (If you don't see a wire connected to this port, usually there are extra wires that not used, you can connect it to the * and the other end connects to the 2nd brown wire from the humidifier.) After connected turn on power, set up Nest under equipment (you can find on You Tube how to set this up.) I installed it yesterday, the whole house humidity went up from 20% to 31% now, upstairs is about 42% now. I called the Aprilaire and was told it will take up to one week to reach 45%. But now I feel much better, wish I have bought this unit long time ago. Hope this helps, let me know if you have any questions. I will be glad to share.