Thermo switch to operate fan in fish house

[Big Dave2]

In my homemade 6.5' x 12' wheel house I have a small, wall-hanging, ventless heater something like the picture below.

 

Mounted above it I have a 12 volt truck fan like the one pictured below.

 

I am forever turning the fan on and off when I am fishing. When the heater kicks in I turn it on and once the heater kicks out there is no sense in having the fan on so I turn it off. 

 

A friend was fishing with me last weekend and saw me doing that and mentioned something called a thermo switch. Is there a way to make the fan go on and off on its own with the help of a thermo switch? If so, what thermo switch do I need and where should I mount it?

 

 

 

[PRO-V]

Mount a line voltage thermostat in line with it.

 

[ZachD]

http://www.electricmotorwarehouse.com/automatic-fan-thermal-switch-for-automatic-operation-of-fireplace-woodstove-fans-115v/?utm_medium=googleshopping&utm_source=bc&gclid=EAIaIQobChMIgp346djR2AIVg7fACh39ugdlEAQYAiABEgKjnfD_BwE#sthash.hJotSuef.dpbs

[PRO-V]

I believe that will turn on fan when heat comes on. He wants the opposite.

[Jim Almquist]

5 hours ago, PRO-V said:

I believe that will turn on fan when heat comes on. He wants the opposite.

 

 

I believe that is just what he wants. Only run fan when heat is on. Should work for 12 volt DC because it looks to create a short when heated up and an open when cool.

[vtx1029]

yep I agree just put a thermostat in it

[rl_sd]

9 hours ago, ZachD said:

http://www.electricmotorwarehouse.com/automatic-fan-thermal-switch-for-automatic-operation-of-fireplace-woodstove-fans-115v/?utm_medium=googleshopping&utm_source=bc&gclid=EAIaIQobChMIgp346djR2AIVg7fACh39ugdlEAQYAiABEgKjnfD_BwE#sthash.hJotSuef.dpbs

 

The heater already has a thermostat built in... what he wants is the fan to run when the heater kicks on. The switch that Zach has listed should do exactly what you are looking for... The only thing that I am not sure of is whether it will open with 12vdc instead of 120vac. What is the amp draw on the fan?

[Sea Hage]

Yes, That switch will work just fine with any voltage up to 120v and it will close when heated and open when cooled. Switches really don't care what the voltage is.

[PRO-V]

Sorry, I misread his original intention.

[Big Dave2]

Thanks guys. I ordered the thermal switch that ZachD posted. I'll see if I can make it work somehow.....

Any suggestions on where to mount it?

 

[PRO-V]

Probably on the upper front sheet metal. Be careful you don't get it where the wires get too hot. The switches usually come in a variety of temp ranges also.  So guess accordingly.

Edited January 13, 2018 by PRO-V

[ZachD]

Well the switch closes at 115 degrees F so you will have to place it somewhere that It reaches that temp when you want it to turn on. I would say inside on the sheet metal top vent would do the trick if you wanted it hidden

If not I guess just stick it on the outside of the vent hole. Or I am guessing it will close if you just stick it on the side of the heater just have the flat part of the switch flush with it I know my heater gets pretty hot pretty much anywhere on the metal basically

I would take a bbq thermometer and find a place that hits 115 when you would want the fan to kick on. 

 

As for the wire go to the hardware store and get some high temp like this its rated to 392 F

https://www.amazon.com/dp/B01KCPL3GC/ref=sspa_dk_detail_2?psc=1&pd_rd_i=B01KCPL3GC&pd_rd_wg=NEE9O&pd_rd_r=NHQPZ29KWH6QT57M7M41&pd_rd_w=aiXqh

 

If you need something higher rated https://www.amazon.com/dp/B01KCPL3GC/ref=sspa_dk_detail_2?psc=1&pd_rd_i=B01KCPL3GC&pd_rd_wg=NEE9O&pd_rd_r=NHQPZ29KWH6QT57M7M41&pd_rd_w=aiXqh

That's rated for 482 F

 

 

Edited January 17, 2018 by ZachD

[Lip_Ripper Guy]

We use a line voltage thermostat, with it set in the "cool" position.  Once it hits the set temp the thermostat kicks the fan on, until it gets below the set point.  Works pretty well.  

[Blackhawkxp]

I used an attic thermostat that has an adjustable on/ off setting similar to the below image.  It turns on at bout 75-80 degrees and then shuts off when the temp drops back down

 

Edited January 19, 2018 by Blackhawkxp

[papadarv]

I had same challange. Went with a 12v temperature relay switch. Heater/Fans in my DIY wheelhouse now functions just like my home or RV forced air furnance. It comes with a small heat sensing probe i mounted on my upper air duct than set the on/off temperature so fans runs/stops when heat kicks on/off. Provides perfect comfort for $15.00.

https://www.walmart.com/ip/bayite-DC-12V-Fahrenheit-Digital-Temperature-Controller-10A-1-Relay-with-Sensor/585224840?wmlspartner=wlpa&selectedSellerId=12524&adid=22222222227093022211&wmlspartner=wmtlabs&wl0=&wl1=g&wl2=t&wl3=213210114658&wl4=pla-345493512458&wl5=9019533&wl6=&wl7=9019476&wl8=&wl9=pla&wl10=117430032&wl11=online&wl12=585224840&wl13=&veh=sem

 

Sensor under foil tape

 

Took photo when furnace was off. Temp range -40 to 230 f. Spare probe to right of controller, copper tube is thermostat, black button is pilot iginter.

 

Total set up with 4 speed auto fan switch. 

Edited January 21, 2018 by papadarv