It runs two zones at same time only from the control panel, in automatic and manual. Manual using the bleed screws works fine. I do not have a multimeter, so I guess I will either have to buy one or hire someone to come out. Thanks for your help.
My system is 22 years old so I probably should expect some issues, so here is my issue. I have 3 zones and just recently zones 1 & 2 are coming on at the same time, both manually and automatically. Checked all wiring at the valves and checked out the control box. It all appears to be working OK. But, obviously there is something wrong. Any solutions or ideas out there. Thank you. TJC