I have a TACO 006 series cartridge circulating pump that I feel needs to be primed. Can you give some general tips that will allow me to do this? The pump is in line to return water through the drain at the bottom of the water heater. I have hot water at the taps (eventually, allowing the water to run) and the pump is running. I believe that the recirculating system needs to be primed. I don't know what to do to get the system to function properly. Please help.