Purge time.

[444dieselrod]

I haven't posted pics yet but I modified my reg cab to burn wvo 6 weeks ago, put a heated tank in the bed, 2 selector valves underneath, a heat exchange under the hood. I set the system up so I can loop heated oil or purge it back to either factory tank, or the wvo tank. Have any of you timed how long it takes to purge the system? I had to do some work last nite on my wvo tank and when I pulled the heater out the top it was almost full! I only drive 5 miles in purge mode but if my calculations are right it pumped almost 5 gallons in purge mode into the wvo tank.