I have a system where it has been working fine for 1 year, right now the Hvac controllers are not working (3 out of 4 ), if i try to set the temperature on the wall controller, the leds (green and red) go up and down, and nothing happens, i have the leds (low battery & link) blinking at the same time (in all of the 3 Hvac controllers)the rest of the system is working fine, any ideas why is doing that?, thanks a lot for the help