If 1 out of 3 loops is working then it is possible 2 of the actuators are not opening.
Replace actuators if needed
If all 3 actuators are opening then there is a possibly of air in the 2 other loops.
These will need purging.
Replace actuators if needed
If all 3 actuators are opening then there is a possibly of air in the 2 other loops.
These will need purging.