Supco 90370 HVAC/R General Purpose Fan Relay, 12A Load, 24V Coil

Relay worked perfectly for Nest Thermostat controlling a gas fireplace. I also had to install a 24VAC transformer. Very simple configuration:1) The N/O switch contact side of the relay is connected across the gas fireplace switch leads.2) Three wire, 18-gauge thermostat cable (red, white, and blue connected to RH, W, and C respectively on the Nest thermostat) was fished through the wall. The Nest was located a few feet from the fireplace about eye-level on the wall. Fishing the wire through the wall was the hardest part of this install.3) Under the fireplace the wire is connected to the secondary 24VAC side of the transformer using the red RH power wire and the blue C common wire.4) The relay coil is connected to the white (W) control wire from of the nest thermostat, with the other side connected to the blue C common wire. In my install, the transformer and relay were tucked underneath the gas fireplace a couple of inches apart.5) Finally, the primary side of the transformer is fitted with a 120VAC cord (only needed to be about 8-inches long in my case) and plugged into 120VAC.6) On my Nest Thermostat, I had to lie to the thermostat and configure it for "electrical heat" rather than "gas furnace" ... I think. I did this and it works. Read it someplace.This is the 4th Nest Thermostat I have in my home but the only one on a gas fireplace, the other three are controlling two other furnaces, one with two zones, and no relay is required for those applications.Shipping was very fast on this product and I have absolutely no complaints. Would buy again... in fact, I'm about to use another of these relays to control my whole-home humidifier... as soon as I can figure out hot to get the additional wire run to the nest. That's another project.

I used your relay for my homemade emergency lighting system and it works perfectly with my LED light and auto charging battery system.

Installed it on my hvac system three months ago. Working good so far.

Yeah good

Easy to install and fixed the problem with my garage heater

I am using these to use ecobee thermostats with my unconventional zone valves. Since my valves are normally-open, they require power to remain closed and the power needs cut for the valves to open. These relays do the job perfectly, and since my old thermostats used a third wire to perform this function, these relays only require two wires to do the same thing, thus freeing up the third wire for me to use as a common wire to power the thermostats.The only issue I have is that one of the two relays I purchased has failed and doesn't switch reliably. This causes that zone's valve to remain open and the rooms get far warmer than they should. Simply wiggling the wire causes the relay to audibly click and start functioning again. I have a replacement on order, so we'll see how that one fares.

Used to wire up a nest thermostat to a milivolt furnace along with a 24VAC transformer.Worked fine but had a bit of a buzzing sound from the start. Since it was in the basement really didn't mind.Would have given it four stars if it lasted more than 8 years, but it did not. Replaced with an Emerson brand equivalent.

I used this in my heat only 2-wire system to add a "C" wire to power the Nest Thermostat.Although the Nest worked without the "C" wire, it was temperamental, especially when the Nest called for heat often. As the Nest only pulls power from the two wires when furnace is NOT calling for heat, the Nest would be erratic if the heater was on often, and the Nest could not get enough power.This little relay solved the problem. By wiring it in with the 24VAC transformer in the furnace, and sharing one of the leads with the "C" connection in the Nest, my Nest now always has power, even when furnace is calling for heat.It has performed flawlessly all winter. No noticeable noise other than a very slight "click" when it energizes, but this happens at the same time the other furnace relay clicks, so it's barely noticeable.Bottom line... if you need to add a "C" wire to a 2-wire heating system, this works like a charm!

Wanted to add a smart thermostat to my 40 year old furnace that would also allow me to turn on the fan from the stat; the furnace only has a heat limit switch with manual "summer" button, no control board. So spliced this into the wiring of the 'summer' button, for remote switching. Works great, no problems, responsive and sturdy.

I got this to help with adding a Nest thermostat to my old furnace. The old girl is an oil furnace that was converted to natural gas and uses a millivolt thermocouple to turn the heat on and off instead of a 24 volt AC system. The ears on the relay worked great for screwing it to the floor joist in the furnace room and everything connected right up and worked great using the diagram on the side of the relay.

nothing fancy , working so far , fast delivery.

I used this relay to switch dry contacts from my clients steam humidifier from his nest thermostat. The nest sent 24v to the relay it then switched voltage to the dry contacts connected to the steam humidifier, client was very happy when the job was done.

Worked for less than 5 months