# Furnace blower timer switch?



## Devil505 (Dec 6, 2006)

I just had a HVAC guy rewire my forced hot air furnace blower so that the blower can be turned on/off by itself (on a separate on/off switch) to circulate my coal stove warmed air throughout the house. It works fine but I want to be able to control it with a simple wall timer switch so that I can run it for short periods of time & have it turn itself off. It's low voltage so I don't know if a regular wall switch timer will work & I don't want it controled by temperature, just time.

Any thoughts?


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## HVACDave (Oct 16, 2007)

Just pick up a simple spring wound timer for a bathroom exhaust fan at home depot and put in place of your manual on off switch and away you go. 

If you wanted to be able to turn it off at any time, then put it in series with the manual switch and both would have to be on for the fan to run and you could shut it off before the time cycle was complete if you wanted to for any reason.


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## Devil505 (Dec 6, 2006)

HVACDave said:


> Just pick up a simple spring wound timer for a bathroom exhaust fan at home depot and put in place of your manual on off switch and away you go.
> 
> If you wanted to be able to turn it off at any time, then put it in series with the manual switch and both would have to be on for the fan to run and you could shut it off before the time cycle was complete if you wanted to for any reason.


Thanks for the reply Dave. I had bought this http://www.homedepot.com/h_d1/N-5yc...splay?langId=-1&storeId=10051&catalogId=10053 but the HVAC guy (not an electrician) didn't think it would work because it's a low voltage line controling the furnce blower fan.
Think I could just replace the on/off swirch with this?


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## HVACDave (Oct 16, 2007)

I think that one needs the 120 volt to operate the timer, that's why I recommend the spring wound type, then it's just a switch, no power required to operate the timer part.


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## Jackofall1 (Dec 5, 2010)

You could always go high tech with this

http://www.nextag.com/24-volt-timer/products-html

Mark


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## Devil505 (Dec 6, 2006)

HVACDave said:


> I think that one needs the 120 volt to operate the timer, that's why I recommend the spring wound type, then it's just a switch, no power required to operate the timer part.





Jackofall1 said:


> You could always go high tech with this
> 
> http://www.nextag.com/24-volt-timer/products-html
> 
> Mark


Thanks guys but I already put one switch box in the wall & I don't think I can sell my wife on knocking another hole! :laughing:
(I'd like to have a switch/timer that will mount in a single electrical box)


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## Devil505 (Dec 6, 2006)

Sorry Dave..._ misread your post & thought you were talking about adding a timer long with the switch I have. I'd like to find a silent electronic timer if there is such an animal._


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## Jackofall1 (Dec 5, 2010)

Ok here one, will fit in your hole in the wall:thumbsup:

Mark


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## lettersoup (Nov 11, 2011)

Devil505, How did your HVAC person make the rewiring to allow for the separate switch? I want that separate switch on the second floor so I don't need to go down to the lower lever to activate the blower from the switch located right on my thermostat.
I thought it was just a matter of adding my switch hooked to the G (which I though controls the blower) and R (24 v hot) terminals, in parallel with the thermostat. It works fine with if the thermostat (Honeywell TH4110D1007-0645) is not pushed into its base plate but once I install the Thermostat back, when I flip my switch on, the AC starts along with the blower, even though I am not connecting the Y wire (which I thought controls the AC) at all. It seems as if the thermostat is causing the connection whether it is in OFF, in HEAT or in COOL, regardless of the temperature settings. 
Thanks.


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## Devil505 (Dec 6, 2006)

lettersoup said:


> Devil505, How did your HVAC person make the rewiring to allow for the separate switch? I want that separate switch on the second floor so I don't need to go down to the lower lever to activate the blower from the switch located right on my thermostat.
> I thought it was just a matter of adding my switch hooked to the G (which I though controls the blower) and R (24 v hot) terminals, in parallel with the thermostat. It works fine with if the thermostat (Honeywell TH4110D1007-0645) is not pushed into its base plate but once I install the Thermostat back, when I flip my switch on, the AC starts along with the blower, even though I am not connecting the Y wire (which I thought controls the AC) at all. It seems as if the thermostat is causing the connection whether it is in OFF, in HEAT or in COOL, regardless of the temperature settings.
> Thanks.


I had the HVAC guy do it so I'm not sure how it was connected at the furnace but I know the thermostat wire was only a 2 wire...so he had to either run a new 3 wire to the thermostat or just bypass it & connect a simple on/off fan switch for me. (which is what I wanted in the basement anyway)


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## bridgerman (Dec 13, 2011)

Devil505 said:


> Thanks for the reply Dave. I had bought this http://www.homedepot.com/h_d1/N-5yc...splay?langId=-1&storeId=10051&catalogId=10053 but the HVAC guy (not an electrician) didn't think it would work because it's a low voltage line controling the furnce blower fan.
> Think I could just replace the on/off swirch with this?


 
Here is a timer that works on the low voltage signals at the thermostat. It doesn't use batteries and is designed to cycle the fan as often and for as long as you want. It is called ThermGuard. It can be installed by anyone in 5 minutes.

www.bearmountaindesign.com

This might help anyone else with a similar problem.

John


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