Two sprinker heads are not going up, in a zone of five heads

[lufia]

Hello!

I’ve had my Rachio 2 up and running for about 8 month, it was working fine until recently I noticed that in my zone 3, which includes 5 sprinkler heads, two of the heads do no pop up while this zone is running. If I pull them up by hand, water comes out as normal, but they retreat back to ground if my hand is off.
Other three heads in the same zone are running fine without pressure issue, other zones are also fine. I am wondering what would be the cause of the problem? The valve and heads are both pretty new, just installed with the controller.
Any ideas or suggestions? What might be wrong and what may I check? Thanks!

[gaustin]

@lufia, you may need to clean the small filter inside the head itself. When the station is not running unscrew the top of the head where the nozzle is and pull out the body. Check the small filter at the bottom and clean if needed and reinstall making sure to line up the nozzle in the correct direction. Good luck.

[tmcgahey]

There is a flow restriction issue somewhere. Check that any valves in the system haven’t been throttled back for any reason, and this includes the zone valve itself. Many model have a restrictor screw that can reduce the flow of the line.