Flow with Circulator off in a Condensate Hot-Water Heating

NB

I installed a single zone Condensate forced hot water system off my steam boiler as depicted in the HeatingHelp.com section way before I found this web site. I got it all right except the by pass loop to control the temperature of the condensate going through the bronze circulator pump. The problem is when it gets really cold and the steam heat is cranking there is flow through the water loop even when the circulator is off. Do I need to pipe in an electric flow valve that runs on the same signal as the pump? If so can you recommend one?
Thank you

NB

Steve Thomas (Foley Mechanical)

Gravity flow

Install a flow control after the pump
Sometimes you will need to add a spring check on the return