The problem is this. A three storey house with a thermostat on each floor connected to a motorised valve, one for each floor. One valve has stopped working, probably blocked. It is located somewhere under the floorboards but is not where we expected it to be. How do we trace its location? Is the only way to start at the thermostat and follow the wire back to the unit? If so which wire goes to the valve? We'd like to avoid pulling up the carpet and all the floorboards.