On the surface it appears that it will work. Here is a picture of the box for that zone. I see power coming in (top), existing two wires from the thermostat (top brown) and wires going to pump (bottom). Is this considered a dry contact switch? It's not clear how I would hook up such a device to this though.
That's a switching relay, and it does not expose the
C terminal (see the PDF).
You may be able to access the
C terminal, but you'd have to disassemble the device. Which almost certainly voids the warranty, and could lead to unrepairable damage.
It appears to me that it would work. Leave the big wires alone. It's the two small stat wires that you will be working with. Treat those two wires as the first example shows in the instructions, the two wire example. Good Luck. P.