Step 1: Turn the power source off to the zone valve by lowering the temperature on the thermostat.
Step 2: Isolate the zone valve by closing the upstream and downstream shut off valves.
Step 3: Disconnect the wiring to the zone valve.
Step 4: Remove the old zone valve. If connected by a threaded connection use two wrenches to backup the piping.
Step 5: Install the new zone valve in the reverse order with two wrenches. Make sure the zone valve is installed in the same direction of flow as the previous zone valve. This is determined by the direction of flow arrow on the side of the valve body.
Step 6: Open the shut off valves once installed. Then check for leaks at the connections.
Step 7: Connect the wiring to the new zone valve. There is no need to worry about polarity in this case.
Step 8: Turn the thermostat back up and test the operation of the zone valve. Double check connections for any leaks. The final steps are purging any air that might have been introduced into the system, then returning system pressure back to normal operating pressure.