I'm working on an old system that has 24 volts at the panel, but by the time it gets through the old wire to the valve, it's down to 12 volts. I assume there is some loss on the line. If we trail a new line out to the valve, it clicks, but through the old line it doesn't. Should a valve work with less than full power, or do I need to go ahead and run the new wire?
