# Making a duct temperature sensor work



## isaactheunknown (Dec 10, 2020)

I need to automate a wooden ductwork system. 
My goal is when the desired temperature is reached, the booster fans turn on and blow the heat in the ductwork.

I tried showing him some amazon plug in type temperature control. He doesn’t want to use it.

I have seen duct temperature controls that use resistance to control the temperature. Is there a simple way to make this sensor work?

I’m more of a commercial electrician and not too familiar with industrial controls.


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## backstay (Feb 3, 2011)

What is your design temperature? What is the fan load. You say you’re controlling a fan, what happens when the duct is too warm. What controls the heat part.


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## isaactheunknown (Dec 10, 2020)

backstay said:


> What is your design temperature? What is the fan load. You say you’re controlling a fan, what happens when the duct is too warm. What controls the heat part.


it’s a 120 volt booster fan with 1.5 amps When the desired trmperature is reached the fan turns on. It won’t get to warm because it is a wood fireplace that gets handfed.


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## paulengr (Oct 8, 2017)

Plenty of temperature controllers out there. Look at Omega Automation. BUT what you are also trying to do is turn an inductive load on and off. So you should consider an MMS (manual motor starter) which has the breaker and overload protection built in. Then this connects to a contactor. The temperature controller relay output will operate the contactor. Then you just need a box. Also get a rotary extension handle for the MMS.

Alternatively if you can get a combination starter that does everything for the motor then the temperature controller solves the issue.

You can do it cheaper if you can find something premade to do the same thing.


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## isaactheunknown (Dec 10, 2020)

paulengr said:


> Plenty of temperature controllers out there. Look at Omega Automation. BUT what you are also trying to do is turn an inductive load on and off. So you should consider an MMS (manual motor starter) which has the breaker and overload protection built in. Then this connects to a contactor. The temperature controller relay output will operate the contactor. Then you just need a box. Also get a rotary extension handle for the MMS.
> 
> Alternatively if you can get a combination starter that does everything for the motor then the temperature controller solves the issue.
> 
> You can do it cheaper if you can find something premade to do the same thing.


I can’t find the temperature control I want. I only see temperature controls that give resistive, current or 0-5v signals. I’m trying to find something like a 120volt signal or at least some 24vac signal at least.


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## LGLS (Nov 10, 2007)

isaactheunknown said:


> it’s a 120 volt booster fan with 1.5 amps When the desired trmperature is reached the fan turns on. It won’t get to warm because it is a wood fireplace that gets handfed.





isaactheunknown said:


> I can’t find the temperature control I want. I only see temperature controls that give resistive, current or 0-5v signals. I’m trying to find something like a 120volt signal or at least some 24vac signal at least.


Why do you just go with a standard line voltage 120/240 V thermostat the thing is you’re gonna need a model that closes on temperature rise and there are a few models I know Honeywell makes one it looks like a wall thermostat for line voltage baseboard heating or line voltage oil burner controls.

If you want to go with the 2416 or 12 V low-voltage control, then all you need is a low-voltage wall thermostat a simple dumb one, without the digital electronic BS. That means all you need is a step down transformer a thermostat like your typical round ones old fashion old school, or your rectangular ones that are mounted horizontally that no electrician ever put it back played in forever except for me I was the one who started that crap on Long Island, which my nonunion boss is considered a waste of a 1900 cover plaster cover, which then morphed into standard operating procedure for all Long Island electricians Ha! Then all you need to do

Then all you need to do is wire and series your thermostat with your transformer and your relay that controls your fan.

Honestly, if the fans load is only 1.5 A I would go with a line voltage thermostat that can do heating and cooling. 

Keep it simple stupid. KISS.

Peace out


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## paulengr (Oct 8, 2017)

isaactheunknown said:


> I can’t find the temperature control I want. I only see temperature controls that give resistive, current or 0-5v signals. I’m trying to find something like a 120volt signal or at least some 24vac signal at least.







__





Thermostats | Controllers | Control Monitoring | Omega


Thermostats




www.omega.com





The first one has a 15 A rating, may not even need a starter, but isn’t in stock. The inljnes are also nice but 6 A limit.


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## backstay (Feb 3, 2011)

Line Volt Mechanical Tstat










Line Volt Mechanical Tstat: 1C


Remote-Bulb Control, 5 1/4in Bulb Length




www.grainger.com


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## CMP (Oct 30, 2019)

If your blower motor is impedance protected, I would consider a remote bulb temperature controller. You likely would not need any additional controls if you picked the appropriate model for your application.









Honeywell Temperature Control


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## Wardenclyffe (Jan 11, 2019)




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