Basic system with recirculation anything else needed?

In another post I asked questions about a recently installed recirculation system. I have just a couple more questions about my system (THANKS AGAIN)!

Below is a picture of what I think my system should look like. Does the PRV also act as a backflow or do I need one of those as well? Is an air vent necessary and where? I don't have the expansion tank currently but from what I have read so far it seems like a good idea.

I would plumb the recirc return line closer to the WH, not before the expansion tank. Some like to plumb it to the drain nipple on the WH.

You need a check valve between the pump and the connection to the cold water line. IF the flow is going upwards, you MUST use a spring loaded check valve. Minor point, but you show the connections to the water heater backwards. An air vent is not necessary, but a shut off valve after the pump, and a purge valve before the pump could be beneficial depending on the actual way the line is installed.

hj said:

You need a check valve between the pump and the connection to the cold water line. IF the flow is going upwards, you MUST use a spring loaded check valve. Minor point, but you show the connections to the water heater backwards. An air vent is not necessary, but a shut off valve after the pump, and a purge valve before the pump could be beneficial depending on the actual way the line is installed.

Click to expand...

Thanks HJ! Wish you live in the SF Bay Area!

The up arrow with the box is the check valve, not sure if mine is spring loaded. But since the water heater is in the attic I'll ask my local supplier for a spring loaded valve.

Thanks for the info on the air vent, do you think I need the expansion tank? I read about water expansion in circulations systems and it seems like it might be necessary.