As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SEA FLIGHT NR 2090 ON PUSH BACK DE-ICE PRESSURE CAUTION REMAINED ILLUMINATED AND PRESSURE GAUGE SHOWED 6 PSI. BOTH PROPS BROUGHT UP TO MAX 785 RPM DEICE PRESSURE RAISED TO 10 PSI. NO CHANGE WITH BOOT AIR ISO VALVE ON OR OFF. REPLACED NR 2 HPSOV PER TASK 21-11-16-000-801/21-11-16-400-801. OPERATIONAL AND LEAK CHECK GOOD. AIRCRAFT RETURNED TO SERVICE.