Burning up 24VAC Irrigation power supplies

[davidjustin]

Thank you so much for the reply! Don't feel bad about the troubles, this is all a learning experience for me, so I take it all in stride. I am very pleased you are willing to help!

Here are the relays I am using: According to this response they are opto isolated (https://www.amazon.com/forum/-/Tx3HQROER...B00KTELP3I)

I have three power supplies:

1. Powering PI, then the six wires from the PI runs to the small shift register circuit. There are two sets of nine wires coming from two shift registers. The 8 control wires and the +5v wire (no ground). The 9 wires are plugged into the grouped header pins on each relay.
   
2. Powering relays. I am using an old Apple USB charger and cable. I have the red +5v wure from the usb cable going to my power distribution board. This is split and running to the small headers where the jumper was removed from the relay boards. +5v is going to the JV-VCC and ground is running to ground on each relay.
   
3. 24vac is on a separate circuit on the power dist board. Before it splits between relays, this is where I placed the fuse block. One side acting as common and is running to the sprinkler valves. The other side is split going to the relays. Each relay has is chained together on the normally open side of the relay, and the middle (common) terminal is where the sprinkler vale wire is connected.  As far as I can tell the 24v is completely isolated. It's possible there is a short in the wiring going to the sprinkler valves, but I am not sure why this would effect the operation of the relays. 
   

I wonder if the USB charger is not powerful enough for the relays? 

Thanks again for the help!!!