It would work as drawn but your scraping in there amperage wise on the main switch which has me thinking about the whole box and what circuit it will be run on, but one thing at a time. the pump is 1.4 (right?)x2 for motor start is 2.8Amps plus the element at about 11.5 and your at 14.3 amps. So that is pretty close but you will most likely have this plugged into a standard 15Amp circuit, and if so you are protected. which I guess makes that concern less concerning. that being said, remember that the NEC has charts to determine wire size on amperage for good reason, a small wire on a 15 amp circuit will quickly burn up its insulation if tasked with carrying more amperage than it is rated for. 14 gauge is good for 15 amps though some of the wires on the 120V AC side can (theoretically) be smaller because they will be carrying small loads but go as big as you can. Also, I dont have a pin out for the SRR but 1 on the SRR is line in right???