Tank would not hold full pressure (1.5 psi) overnight. Removed float switches, sump plug and low fuel warning sensor. Applied tight-seal compound to threads on above components and re-installed. Found that sump plug was the problem. Tank now holds pressure.
Fabricated various flair fittings/tubes/hoses and Facet transfer pump to fill tank and test. Pumped one gallon fuel into tank and vigorously shook tank in all attitudes to flush any possible foreign matter. Set tank on bench in exact attitude that it is in the airplane. Pumped one gallon at a time into tank and marked level on tank. Tank holds 14.5 gallons when filled to max capacity. Rigged pump and filter to take fuel from the sump, run through a filter and return to tank via filler tube in order to remove any unwanted particles. Ran pump for 15 minutes using #1 filler tube.
