running sprinkler wire and power in same conduit?
From an NEC standpoint, the main deciding factor about running different voltages in the same conduit is that the conductor insulation must have the same voltage rating on all wiring. Standard residential insulation is 600V so the control wiring must have the same rating. Low voltage wiring usually are rated at 300V. So needless to say this would not be allowed.

Keep in mind I am not saying this is a good installation. There are many other reason why I would not like your installation. I am just saying it could be done if it made the above requirements.

Good luck