EmersonThermostats 90-290Q Fan Relay SPST

I used this relay to hook up my honeywell whole house humidifier to a Nest thermostat. Previously, I purchased a different (and more expensive) relay from amazon that only worked a couple of weeks, so I decided to try this one. So far so good. It works perfect, but I have only had it for 1 day, so I will update if anything goes wrong with it in the future. 1 bonus of this one vs the other, this one is MUCH quieter than the other one. It's a relay, so they do click when engaging and disengaging, but you can barely hear this one turning on and off, even standing next to it. I could hear the other one anywhere in the house when it would turn on and off.

Used to add a whole house humidifier to my HVAC and Sensi thermostat. Worked perfect.

thanks to chat gpt and process or elimination using logic you can fix your furnace instead of wasting money hiring someone or buying a new one. This part did the job!

Good price exactly what I needed.

My oil furnace was not compatible with smart thermostats; it only had two wires running to a mechanical thermostat. With this relay, I was able to add a 24VAC transformer and this relay to my oil furnace to connect a Honeywell T9 WiFi thermostat. You should be able to use this for any smart thermostats (like Nest or ecobee) that need a 24V C-wire.So far, it has worked great. While there are many YouTube videos that describe how to connect the wiring, know that you will be working with both 120V and 24V electricity and should consider hiring a professional if you do not know how to do this safely.

I used an existing grounding screw and was able to mount the relay without drilling any holes. I had to do some googling to figure out how to wire it to my Nest thermostat and my Aprilaire 600 humidifier. I removed the existing manual humidity control and the current sensing relay on the blower motor. It was easier than it sounds and works great!

Did exactly what I needed in order to control my Aprilaire 400M humidifier using the signal wire from the Nest humidifier control lead and incorporating it so that the 24-volt transformer can properly control the humidifier water supply solenoid. Only reason I'm not giving it five stars is that it makes a slight buzzing sound when it's energized after the heater turns on during it's cycle. I have noticed the sound has diminished somewhat now since I first installed it 2 months ago, but it is still faint. Was definitely worth the money so that my Nest could control humidity the house.

Relay worked perfectly. Exact duplicate of OEM relay. Easy installation.

Worked well with nest learning thermostat Gen 3.Make sure to have female spade terminal

Received the item and it worked as it should, but it had an annoying buzzing sound. Was sent a brand new one quickly and it was quiet. Would buy again

Check carefully before ordering as there are many similar looking relays with different pin counts and functionality.This one worked perfectly for my old Nortron electric furnace... until I replaced it with a new Nortron electric furnace!

Got this to enable Nest Learning Thermostatto control gas fireplace. Works great. (Note: required also a 24VAC transformer to power thermostat)

Works well. This is my 2nd one ( installed another at previous home). Use it with Nest thermostats and a humidifier. No instructions so it’s not completely dummy proof. No issues with either after install. Second one is going on 4 years