Turning a pump off when a blower comes on

I'm trying to set up a little automation project. I have a wood doctor, a wood-fired water heater. It has a temperature controlled blower. I would like to use the blower turning on to turn the circulating pump off for a time interval. I have everything sorted for turning the circulating pump off and on, but not the input from the blower. Any suggestions would be appreciated.

You could wire a relay in parallel with the blower motor and check to see if the relay is closed. Or you might use a current sensor on one of the blower lines. This also allows you to monitor the current draw of the blower motor

Thanks, that makes sense, I didn't even think of using a current monitor.

The open energy website has excellent design info for the non-invasive sensors.