Vacuuming out the water lines
Has anyone tried using a wet/dry vacuum to empty the water out of the fresh water pipes? I do not know what kind of suction pressure the plumbing can withstand. Is this a bright idea?
Forum Discussion
naturist wrote:
Maximum possible pressure to move the water is 15 psi and that’s at sea level. That will be less effective than an air compressor at 80 psi. Might work, though. Give it a try and let us know how it works.
You don't need anywhere near 80 psi to blow out water lines; around 5 psi (about 138 inches or 11.5' of water) would in theory suffice for most any RV.
A shop vac on the blower setting, if one could adapt it to the water inlet and had a good enough filter to keep dust and debris out of the pipe, would probably work just fine. I don't know what the maximum static pressure they develop is on the blower side, but they do produce a large volume of air which is a big help in blowing out the water lines.
Suction could work as well but rigging up a suitable adapter for e.g. the low point drains might be rather tricky. A shop vac does work very nicely for removing water from residential toilet tanks and bowls if one needs to winterize a residential water system. (You remove the water and then put some antifreezing solution in the trap of the toilet; if the water isn't removed from the trap, the antifreeze gets diluted a fair bit.)
