Well, just talked to the guy at gpi pumps about this. I was concerned with the bypass circuit causing more strain on the pump. He said no problem, pump has a 15 min max run time, just don't go over that.
Running pump with nozzle closed in bypass mode will not hurt anything for a short amount of time(15min max).
Reason I called them was my swivel connection at the nozzle hose connection leaks bad when it hasn't been used for a month or so.
After using it 1 time and having it leak all over the place, seems next time its used with in a few hours, it doesn't leak a drop. And if used again within a few weeks, doesn't leak a drop. Wait a month or 2, and leaks all over again.
So I thought the o-ring at the swivel was getting dried up in storage and leaked till it got 'wet again' and swelled up. The guy at GPI sent me a o-ring rebuild kit for the nozzle, and a new set of upgraded material gears, just in case my gears swelled up. The pump hasn't needed any gears yet and has worked flawlessly for me for years. But a set of new gears in my TH tool box can't be a bad thing...
The customer service guy/technician/engineer? Brian, I talked to at GPI was great.He had been to Glamis before working on the pumps when WW switch from Graco to GPI because of the problems with the fuel pumps. He knew exactly what my problem was and sent everything out quick.
Don't want to start a run at GPI, but the customer service and price was more than right. Class act operation at GPI...
jmo