The water path is blocked. Three likely culprits: a closed valve, a kinked tube, or a wrong connection.
- Confirm the feed water adapter valve and cold water supply valve are open (handles in line with the tubing).
- Check every length of tubing for a sharp kink or crimp that would block flow.
- Verify all tubing connections against the diagram: red (feed water to stage 1), black (flow restrictor to drain saddle), yellow (T-fitting to tank valve), blue (final stage to faucet).
- Ensure the tank shut-off valve is open (parallel to the yellow tube).
If those are correct, you may have missed the initial flush step. To clear carbon from new filters, disconnect the tube to the RO membrane housing cap, open the feed water valve, and flush the first three stages into a bucket until water runs clear. Then reconnect the membrane line.
After reconnection, open the RO faucet and slowly open the feed water adapter, checking for leaks. Water should trickle out within 5 minutes.