I am replumbing an old Therma Spa that has 17 jets. The pumps were replaced with two, 2 speed, 2 HP units. Only about half of the jets can be on at one time due to the valve routing. Can I add more jets or at least remove the valves and use all the jets at the same time? I have attached a drawing of the current plumbing.

Thanks

It's easily done.

Cut out everything and start from scratch, ignoring the original diagram.

I recommend removing the blower valve for the 'turbo-boost' function (to the jets) and simply adding some air control knobs and conventional air intakes to the jets.

Plumb the blower directly to the blower injectors only - that is, if you have them. If not, then eliminate the blower.

Hope you're not planning on using the original jets - that's going to be a really nasty job if you do, and you may not like the results.

And yes, 2 x 2hp pumps can easily run 17 jets, provided the jet output orifice sizing is right.

Optimum jet flow rate is about GPM rates and Orifice size, not HP and number of jets.

Thanks

I found out my drain intakes are bad, so starting from scratch might be the way to go. Should I use the jet housings I have or get all new jets and housings? If so which ones?