I have purchased two Rachio 3 controllers for my 24 zone irrigation system: one 8 zone Rachio 3 and one 16 zone Rachio 3. My gardener did the installation and this was the first time he installed more than one controller to a system. He connected the system’s common wire to the 8 zone controller’s C terminal, then used white wire to connect the 16 zone controller to the 8 zone controller using the C terminals. I told him I think it’s wrong after reading the installation guide and said we need to use the Isolators, one per controller. He doesn’t think that is necessary, as long as we never operate both controllers’ zones at the same time. Is that correct? Even using the Isolator the installation guide says not to operate both at the same time. Thanks in advance for any help.
