Hi,
Looking for a cheap but reliable solution.
I want a fan to turn on when my thermostat is on. Is there a gizmo that would do that for me. My fan is line voltage.
Many thanks in advance,
Sam
Hi,
Looking for a cheap but reliable solution.
I want a fan to turn on when my thermostat is on. Is there a gizmo that would do that for me. My fan is line voltage.
Many thanks in advance,
Sam
Yes, there are several different ways you could get that to work, but I don't have enough information to suggest any in particular.
The best solution will be found by consulting with your electrician.
Jon
Hi Jon,
Thanks a lot.
Please suggest one if you can. For example, something that would turn on an outlet when the thermostat turns on.
Thanks again
Sam
The "gizmo" is typically called a "relay".
The input, or coil voltage, should match the voltage on the thermostat wires. When power is applied, the coil would close a set of contacts that are rated for your line voltage.
Something like this is typically used as a fan control:
However, using something like that to control an outlet might not be code-compliant.
Sam, to my knowledge there is no product sold for this purpose. To accomplish what you are trying to do would entail knowing information about what kind of heating you have (which I don't have), in addition to knowing how it is wired, and then modifying your existing electrical wiring in a manner which is safe and follows code.
This would be a custom job, which unless you are knowledgeable about electricity, would entail consulting with an electrician.
Jon
What you want is a relay, where the 12 volt line from your thermostat closes a switch to allow 120 v house current to flow. I would guess that such things are available at your local electrical supply store, although I've never used one myself.
Paul
P.S. I am *not* suggesting that you run out and buy the device I supplied the link to.
I am simply responding to: "I want a fan to turn on when my thermostat is on. Is there a gizmo that would do that for me?"
I have replaced such relays on my furnace to control the furnace blower, but I certainly wouldn't wire an outlet off of one of those. I can't imagine that such an installation would be code-complant.
To accomplish your goal, I totally agree with everything Jon has said: Call a professional.
How do you know that he has a 12 volt line from his thermostat?
How do you know that he has a 12 volt line from his thermostat?
He wouldn't, It would likely be 24 volt, unless it's electric heat
Depending upon the type of heating system you have, this may not be a big deal. For example, in a typical hydronic heating system the low voltage thermostat, via a switching relay, turns on a 120 volt pump. If you have such a system, you can just parallel a line from the pump to your outlet. Of course it also depends upon what this outlet will be powering as there are limits determined by the capacity of the controls involved.
You need to supply a LOT more info about what you're trying to do.
If the thermostat is the cause, consider monitoring the effect. For example. I wanted to monitor the on-time of my furnace. Instead of wiring into the furnace (cause), I put a wind vane on a microswitch at one of the output registers (effect) and used that. NO wires, no safety issues, no code issues, no furnace warranty issues and best of all, no denizens at alt.home.repair giving me grief about it.
Another option is a parallel process. Use a second thermostat to control your fan.
A LOT depends on what you're trying to accomplish.
re: "If the thermostat is the cause, consider monitoring the effect.
The cause of what? Monitoring the effect of what?
Wild guess here:
The OP wants to plug a fan into an outlet to help circulate/move the air that the furnace puts out.
Easy, a line voltage thermostat can be obtained from many places.
TDD
We don't know 'cause the objective was not stated. In my case, the thermostat was the cause, air movement out of the register was the effect. For my purposes, either would have worked. Sensing the air flow was WAY simpler and safer.
Called logical inference. If you see brake lights ahead, you can be pretty sure that the driver is pressing on the brake...at least sure enough that you'd take action to avoid running into her.
You're welcome to guess, but that doesn't shed much light on the actual problem being solved.
In my case, the furnace runs so infrequently that a fan to prevent stratification has significant effect on "comfort".
Actually, there are such products sold. There are HVAC relay modules available to control AC loads from the usual 24V thermostat signals. There are also some current sensing products sold that can switch on an outlet when a particular AC load is on (like a furnace), though they are most commonly use to turn on dust collectors when starionary woodworking tools are turned on.
Easy to do by any electrician. You need a 24V relay, a box to house everything, a cord and plug, wires to the thermostat.
When the thermostat calls for heat, it sends 24 volts to the heater. You tag on to those wires and run a set to the relay. The relay is like a magnetic switch that closes the 120V contacts. You need to bring power in to the relay, then power out to a receptacle or proper cord that the fan is plugged into. All of this has to be assembled and mounted in a safe manner inside a box.
Parts would be about $40, about an hour labor charge for the electrician. There are also home hobbyists or maintenance guys at work that love to do this sort of thing too. Ask them about it.
Most are 24 volts AC.
And even then it would be 24 volts unless it was a "line thermostat".
A "line thermostat" would handle switching the receptacle all by itself.
I know that...I was asking Paul how he knew to recommend a relay "for the 12 volt line from the OP's thermostat".
Since the OP never supplied that information, the best any of us can offer is what I offered earlier:
"The input, or coil voltage, should match the voltage on the thermostat wires."
The only part of the thermostat that turns on the fan is the fan switch if he has one. Otherwise the thermostat calls for heat or cooling. When the fan gets turned on depends on what kind of forced air system he has. He was never clear on if he wanted the power on when the fan was on for both cooling and heating. Or even if he had both heating and cooling. A relay is probably the mst practical and code compliant solution. But if you didn't care about long term maintainability you could just run a piece of 14/2 from the fan in the furnace.
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