I have a gas fired boiler that uses seven Honeywell Synchron valves for zoned heating. All the valves are model V8043E1012. One of the valves seems to be stuck in the on position regardless of the thermostat setting. Also, I noticed the slide switch (auto or manual) on the valve in question has little resistance when compared to the other six good valves. Any ideas what is going on? Can I repair the valve without removing the entire component?