Question
I have an Irritrol control System, with 2 zones - 2 solenoid Valves, the Valve Box says HR Products, but have no idea what's inside, there's no model identification. Try to search on HR Valves but didn't find anything similar. Anyway, both valves refuse to open, power supply seems ok, between 24 and 26 Volt. Pressure also seems ok. But not even completely bleeding the valves I can have water. Randomly When I fill with water (hose), to remove air from water pump and first valve (got a pipe outlet there), sometimes it opens the valve, when I manually run the zone and bleed it, but this doesn't happen consistent, so not sure if this is a good solution. Normally after a week of this "treatment", the valves out of suddenly start to work on automatic, and I will not have to worry anymore about them. But this summer seems they are not going to cooperate. What I'm missing here?

Answer
Did you check the power at the controller or at the valve?  It sounds like intermittent power at first consideration.  But try adjusting the valves as well, by closing them all the way, then open back up halfway or a little more.  Make sure that your water supply is open all the way, and functioning correctly.  Also make sure that the electrical connections, especially the common wire, have good connections at both the valve and the controller.