Raylo

Yes indeed. But the hot water needs to walk to the cold side when you want it too, whether the pump is on or not. That's how these things work. The hot water flows in the hot leg from the water heater to the mixing valve at the remote sink then feeds back to the hot water heater via the cold leg and stops when it reaches the setpoint of the thermostatic mixing valve (95 deg F). Having one just one line with a check valve would render the system useless.

These systems don't come with the solenoid and check valves and I found that the natural circ potential was such that the system was always "on" whether the pump was running or not hence the need to be able to open or shut off the recirc flow path to engage it when needed and turn it off when not needed. The loop with the check valve allows cold flow to the faucet when the solenoid closes off the recirc path whilst preventing recirc through itself.

I have an overall drawing I need to convert to a .doc file and I'll post it later. This should make it clearer.