Last year I bought a home that has a 6 person spa built into the deck. The owner told me that the pump, spa pack, and panel had recently been replaced.
The pump is a Emerson SPH20FL2CS pump - 230v 10 amp 3450rpm 2hp 2400w main mode and 3 amp 750rpm 1/4hp 720w circ mode.
This is the only pump in the system.
When I drained and refilled the tub last month, I noticed that the circ pump runs, but when I press the button to turn on the jet s, the pump clicks and the pump gets louder, but only a little more water is pumped, just barely enough to disturb the water's surface.
I foud the section on airlocks under spa support, illustrating the pump's wet end, and in looking at mine, the wet end appears to be upside down. There is a vent at the bottom of the wet end, and one half way up. THe water exits at the top, rather than the illustration online.
Can there be a reason for this? I'm not sure I can rotate it because of how my plumbing is.

I am new here, any help is appreciated.

Cheers,

Brad

Is the pump below the water level of the spa? My first thought is that you have a restriction somewhere, such as a valve. Air locks can cause problems, but most often if the pump is below water level and not a circulation pump (small, tiny pump in some spas) it will self-prime. If you have water comming out the top drain plug (yup, drain plug, not vent) then your pump is under water, and would self prime.