retrolefty:
dc42:
How much current do the 24VAC solenoids need? You can almost certainly use opto triacs to switch them, which would be quieter, cheaper and smaller than relays. For example, http://www.farnell.com/datasheets/1244301.pdf will switch 0.9A.They appear to actually be 24 volt DC latching relays as the drawing of the control box shows a diode being used to half wave rectify the 24vac to drive the latching relays.
Lefty
The data that the OP refers to says 24VAC at 325mA, or 30-38V half or full wave or pure DC. As long as it's not smoothed DC, the opto triac I suggested should work fine. It costs only GBP 0.32 from Farnell.