I have a pool with a regular Hayward Superpump, a spa pump and a Hayward millivolt heater. The spa is one of those ones built into the pool deck and the pump for it has its own switch on the wall. My question is....When I turn on the spa pump and heater and change the direction of water flow, am I supposed to turn OFF the "main pump" and only let the spa pump run? I could swear the former operator told me to always leave the pool pump running even when heating the hot tub but when I tried that tonight there was banging in the pipes and shaking so I had to turn it off. I must have misunderstood or maybe i did it in the wrong order. I would greatly appreciate it if someone could set me straight. Thank you.