Mr ADHD
Well-Known Member
Im almost done building my grow room AKA a 6' tall rubbermade cabinet. Im planning on using 2 bathroom vent fans for temp control. Units such as theese will work great: http://www.comfortgurus.com/product_info.php/products_id/283
Im a HVAC/R service tech by trade so I figured Id rig up a cheap and easy DIY thermostat control.
Heres what you will need:
your fans
a cheap non mercury type AC thermostat (lowes oe home depot about $30)
a DPST relay (Double Poll Single Throw) (check ebay or local electrical supply house)
a 24v AC transformer (local electrical supply maybe lowes or home depot)
2 colors of 14gauge wire
2 colors of 18gauge wire
some wirenuts
a 12gauge ext. cord
insulated female spade terminals
Install your fans and mount the thermostat inside the cabinet at about the same level as the top of your plant
mount your transformer and relay somewhere away from moisture (outside/ontop of the cabinet in my case)
Cut off the female end of the cord and peal back about 3-5 inches of the outer jacket
You should have a green wire, a white wire, and a black wire
Run your ground wires from the metal case of the fans and the metal base of the transformer to the green wire on the plug using 14g wire and a wirenut
locate the 120v L1 wire on your transformer and run it to the black wire on the cord. Also run 2 14g wires to where your relay is. you will have a total of 3 black 14g wires wirenutted to the black wire on the cord.
Run a different color 14g wire from the neutral wires on your fans to the white wire on the cord. Also run a wire to the 120v neutral wire on your transformer. You will now have 3 wires attached to the white wire on the cord.
Time to run the low voltage. you will see several terminals on your thermostat including Y,R,G, RC, B,L,C,O
We only need to worry about Y , G , and R. If there is a jumper inplace between RC and R LEAVE IT INPLACE.
Locate your 24v wire(should be red) on your thransformer and extend/conect it to the R terminal on the thermostat using 18g wire.
Run a wire from the Y terminal over to your relay and let it sit for the time being. You also need to place a jumper wire inbetween terminal Y and G on the thermostat.
At this point you shoould have two 120v wires ran to the relay and one 24v wire.
crimp a femal spade terminal to the end of each wire.
attach the 24v wire to one end of the relays trigger coil.
attach the two 120v supply wires to the comon terminals of the relay.
You should have 3 unused terminals on the relay at this point.
extend the 120v L1 wires from the fans using the same color 14g wire you used for L1 previously. Attach a female spade terminal to both wires and conect them to the NO (normaly open) terminals on your realy.
Now you should have one unused terminal on the relay.
Run a different color 18g wire from the 24v common wire on the transformer to the remaining trigger voltage terminal on the relay.
Your done wiring!
you can now plug in the cord and test.
We wired the thermostat to turn the fan on in two ways:
1: by setting the thermostat to cool w/ the fan switch on auto your fans will come on whenever its warmer then the thermostats set point
2: You can manualy turn the fans on by turning the thermostats fan switch from auto to on.
I drew up a wiring chart in paint, hope it helps
I will be updating this post w/ pics in 2 weeks when I get paid and can pick up the materials.
Im a HVAC/R service tech by trade so I figured Id rig up a cheap and easy DIY thermostat control.
Heres what you will need:
your fans
a cheap non mercury type AC thermostat (lowes oe home depot about $30)
a DPST relay (Double Poll Single Throw) (check ebay or local electrical supply house)
a 24v AC transformer (local electrical supply maybe lowes or home depot)
2 colors of 14gauge wire
2 colors of 18gauge wire
some wirenuts
a 12gauge ext. cord
insulated female spade terminals
Install your fans and mount the thermostat inside the cabinet at about the same level as the top of your plant
mount your transformer and relay somewhere away from moisture (outside/ontop of the cabinet in my case)
Cut off the female end of the cord and peal back about 3-5 inches of the outer jacket
You should have a green wire, a white wire, and a black wire
Run your ground wires from the metal case of the fans and the metal base of the transformer to the green wire on the plug using 14g wire and a wirenut
locate the 120v L1 wire on your transformer and run it to the black wire on the cord. Also run 2 14g wires to where your relay is. you will have a total of 3 black 14g wires wirenutted to the black wire on the cord.
Run a different color 14g wire from the neutral wires on your fans to the white wire on the cord. Also run a wire to the 120v neutral wire on your transformer. You will now have 3 wires attached to the white wire on the cord.
Time to run the low voltage. you will see several terminals on your thermostat including Y,R,G, RC, B,L,C,O
We only need to worry about Y , G , and R. If there is a jumper inplace between RC and R LEAVE IT INPLACE.
Locate your 24v wire(should be red) on your thransformer and extend/conect it to the R terminal on the thermostat using 18g wire.
Run a wire from the Y terminal over to your relay and let it sit for the time being. You also need to place a jumper wire inbetween terminal Y and G on the thermostat.
At this point you shoould have two 120v wires ran to the relay and one 24v wire.
crimp a femal spade terminal to the end of each wire.
attach the 24v wire to one end of the relays trigger coil.
attach the two 120v supply wires to the comon terminals of the relay.
You should have 3 unused terminals on the relay at this point.
extend the 120v L1 wires from the fans using the same color 14g wire you used for L1 previously. Attach a female spade terminal to both wires and conect them to the NO (normaly open) terminals on your realy.
Now you should have one unused terminal on the relay.
Run a different color 18g wire from the 24v common wire on the transformer to the remaining trigger voltage terminal on the relay.
Your done wiring!
you can now plug in the cord and test.
We wired the thermostat to turn the fan on in two ways:
1: by setting the thermostat to cool w/ the fan switch on auto your fans will come on whenever its warmer then the thermostats set point
2: You can manualy turn the fans on by turning the thermostats fan switch from auto to on.
I drew up a wiring chart in paint, hope it helps
I will be updating this post w/ pics in 2 weeks when I get paid and can pick up the materials.
