Hi, My pool sweep is not working right now. When I checked on it there was lots of water and bubbles coming from the pressure relief valve. I think this is the reason the pool sweep is no longer working. We have a Polaris F5B...which I think is part 9-100-9002? It looks to me like it's missing a cap to the unit so I can see into the valve. Is there supposed to be a cap on the pressure relief valve? Let me know.