Glenn's original Post No. 1 contained the following headline which does not show in the quote below:
"Draining Fresh H2O Tank"
Originally Posted by PSU1981
Just Sanitized the fresh H2O tank & now draining - my FC 27FB 2015 has the white poly drain & 2 brass ones - can I use all 3 or do I just have to use the white one - that's taking forever.
As you can see Glenn, the variety of advice here covers most possibilities. Could you possibly fine-tune what you want to accomplish, per the following post from earlier today?
Originally Posted by OTRA15
Ditto to most of the new comments.
Seems to me that there are at least three possible projects underway here, which only Glenn (OP) can clarify:
1. Drain only the fresh water tank:
2. Drain hot and cold plumbing lines at low-point drains (but don't winterize any further):
3. Perform a full winterization including compressed air, RV antifreeze, etc..
Until Glenn clarifies his goal, the advice here will remain cluttered and unclear IMO.
Moving on to the recent question from twobikes:
Originally Posted by twobikes
With the low point vents open wouldn't you just turn on the pump and force it out?
Turning the pump on, assuming there is any water left in the tank, would force water out of the hot and cold low-point drains which are "downstream" of the pump, but someone should be ready to turn the pump off quickly so as not to burn it out, as there is probably little if any water left in the fresh water tank.
Turning the pump on will NOT force any water out of the white plastic tank drain, which was the original poster Glenn's main original question IMO. [see quote at top, including Glenn's original headline above it in bold font]
Again, if Glenn would make clear exactly what he is trying to accomplish, we might be better able to offer meaningful advice IMO.