Added variable speed control dial to my 21C Heng stock range hood fan

[viator36]

I added a variable speed control dial to my 21C stock Heng range hood fan. The part is a PWM Low Voltage DC Motor Speed Controller and it was a fairly easy mod. I needed to move the U shaped wire cover piece behind about 1/2 to the right so it will cover the speed controller piece and drill a hole on the face plate. The range hood steel shell turned out to be really hard and my Dewalt drill bits wouldn't work so I had to use some other bit. On the controller circuit board there are words and +/-markings to show how to connect the four wires so you can't go wrong. Adding a couple of spade connectors and wire connections and it's up and running.

The linked video shows the fan noise levels at full power, 2/3 and 1/3, and it quiets down quite a lot at 1/3 power but I feel the most useful range of this controller is probably around 1/2 to 2/3 for a useful mix of good ventilation and reduced noise levels. Of course you can set it at any speed on the dial you want and it has a shutoff too. It may not be as good as the SAM-1 replacement alternative but for less than $10 I am happy with the result.

https://youtu.be/pq1kYT5UR40

[rubicon327]

Jake: Neat mod. Just make sure the outside flap is still lifting at the lower speeds.

[C&G in FL]

Originally Posted by viator36

The range hood steel shell turned out to be really hard and my Dewalt drill bits wouldn't work so I had to use some other bit.https://youtu.be/pq1kYT5UR40

For future reference, the key to drilling stainless steel is to drill at low speed and use kerosene as the cutting fluid. Works well on horizontal surfaces or on a drill press. On fixed vertical surfaces, keep dipping the drill bit in the kerosene.

[tdf-texas]

Originally Posted by viator36

I added a variable speed control dial to my 21C stock Heng range hood fan. The part is a PWM Low Voltage DC Motor Speed Controller and it was a fairly easy mod. I needed to move the U shaped wire cover piece behind about 1/2 to the right so it will cover the speed controller piece and drill a hole on the face plate. The range hood steel shell turned out to be really hard and my Dewalt drill bits wouldn't work so I had to use some other bit. On the controller circuit board there are words and +/-markings to show how to connect the four wires so you can't go wrong. Adding a couple of spade connectors and wire connections and it's up and running.

The linked video shows the fan noise levels at full power, 2/3 and 1/3, and it quiets down quite a lot at 1/3 power but I feel the most useful range of this controller is probably around 1/2 to 2/3 for a useful mix of good ventilation and reduced noise levels. Of course you can set it at any speed on the dial you want and it has a shutoff too. It may not be as good as the SAM-1 replacement alternative but for less than $10 I am happy with the result.

https://youtu.be/pq1kYT5UR40

Great idea! Just one suggestion - the regulator you linked to specifies to not use it on battery power - "it is not recommended to supply power greater than 12V, such as 12V lead-acid batteries, which may cause damage to the governor".

Maybe this model instead? https://www.amazon.com/Onyehn-Contro.../dp/B07GP72BWV

[viator36]

Originally Posted by tdf-texas

Great idea! Just one suggestion - the regulator you linked to specifies to not use it on battery power - "it is not recommended to supply power greater than 12V, such as 12V lead-acid batteries, which may cause damage to the governor".

Maybe this model instead? https://www.amazon.com/Onyehn-Contro.../dp/B07GP72BWV

Hi Tom, thanks for your suggestion. I saved the part you linked in my wish list and if my current one and the spare fail in the future I'll replace them with this one. I'll update this thread if that happens.

[tdf-texas]

Originally Posted by viator36

Hi Tom, thanks for your suggestion. I saved the part you linked in my wish list and if my current one and the spare fail in the future I'll replace them with this one. I'll update this thread if that happens.

Of course since you have a spare, the first one will never fail!

And keep in mind that I tend to over engineer everything. If a part could fail, re-design it so it can't.

[viator36]

Originally Posted by tdf-texas

Of course since you have a spare, the first one will never fail!

And keep in mind that I tend to over engineer everything. If a part could fail, re-design it so it can't.

Before I decided on this part I did notice it says it has "a self-recovery fuse 2A" and "if the current is too large, it will be automatically disconnected, and the fuse will automatically recover after cooling." So will this protection circuit prevent damage when voltage gets into low and mid-13 volt and higher? I understand voltage and current are two different things but I am not that good at things electrical so I'm open to expert advice. TIA!

[viator36]

Originally Posted by rubicon327

Just make sure the outside flap is still lifting at the lower speeds.

Dave, I just checked the flap opening again, at 1/2 dial turn the flap is 2/3 open, and at 1/3 turn the flap is half way open. That should be fine and I don't intend to use the dial at less than 1/3.

Originally Posted by C&G in FL

For future reference, the key to drilling stainless steel is to drill at low speed and use kerosene as the cutting fluid. Works well on horizontal surfaces or on a drill press. On fixed vertical surfaces, keep dipping the drill bit in the kerosene.

Hi Carl, thanks for the tip, I'll try to remember it.

[tdf-texas]

Originally Posted by viator36

Before I decided on this part I did notice it says it has "a self-recovery fuse 2A" and "if the current is too large, it will be automatically disconnected, and the fuse will automatically recover after cooling." So will this protection circuit prevent damage when voltage gets into low and mid-13 volt and higher? I understand voltage and current are two different things but I am not that good at things electrical so I'm open to expert advice. TIA!

The limit on the speed controller is the voltage rating of the components. The amp draw can be within tolerance but the voltage too high and it will fail. It is rated for 12v max - my trailer with solar gets several volts over that. Sorry!

The other speed controller I linked is rated to 35v, 5 amps, and the same price. For someone wanting to do your mod, it would be a good choice.