I cannot imagine it taking very long. On the 27 SBU, it only took about 15 seconds to get some flow. If the pipes were stone empty, it might have taken a minute for the high pressure switch to turn off the pump.
Foard County News & Sassy Schoolmarm
with Lady & Chloe, 2013 39 days, 2014 59 days
2017 GD Imagine 2800BH
'07 GMC Sierra 2500HD Diesel 4x4 Why I got into RVing & More Fun