Controlling 120v VS pump with a dimmer switch

[andrewpasetti]

Hello. The variable speed switch on our old jacuzzi recently broke. The 120V 11.5amp 50/60hz motor is still functional but parts are no longer available. I tied the switch wires (see pic) and was able to control the speed using a 120v 60hz household dimmer placed directly on the line feeding the pump but am curious about the durability/safety of this choice or if there's a better option. We're replacing the tub next year.


Thanks.

 

[Avo Mk8]

Assuming the dimmer is this one :

https://assets.lutron.com/a/documents/0301951.pdf

I don't think it's up to the job.
It's rated at 600W for a resistive load, which equates to 5A at 120V.
You have I think a bit of an inductive load, which as you point out can be up to 11.5A, more than double the rating of the dimmer.
If you want to do this, I would suggest you seek a controller designed for that load, but hacking a circuit on a hot tub with non-original parts is a big safety responsibility, and I would not do it if other perople were going to use the tub!