Hi Carlos,
There is an electrical component (recoverable fuse) on the circuit board which limits the output current to 750mA. Please check the resistance of the valves and the pump or master valve which should be larger than 20 Ohms.
To measure the resistance of the zone valve, remove the common wire and the zone wire from the slots and set your multimeter to Ω mode.
To measure the resistance of the pump or the master valve, remove the common wire and the M wire from the slots and set your multimeter to Ω mode.
Thanks,
Netro Support