Cannot get Sainsmart 8 Channel SSR board to turn on sprinkler's 24 V solenoid
You didn't link to the relay module in question (I see you're new so no worries, please try to do it next time ;-)) but I'm assuming it's this one.  

If this is the case, then I think you have mistakenly connected the 26.6 VAC supply to what is meant for a 5 VDC supply. If you have this is not good, hopefully it hasn't blown anything (very possible though)  

The marking are actually VCC (not VOC) and GND. TO these you need to connect a 5VDC supply as mentioned.  

Here is a schematic of one of the relays on your module:



Notice the 5V on the input side of the relay. The "switch" is from pins 3 and 4 with a fuse in series.  

For the relay connections, they act like a single pole single throw switch (SPST) and need to be in series with the power source. To switch the power to the solenoids, you need one lead from the power supply (either one as it's AC) to one of the relay terminals, then one of the solenoid leads to the other terminal. Finally the other lead from the solenoid connects to the other supply lead.
Just try to think of the relay as a simple switch.