Refilling empty water tanks - how long for the air to push out?

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thelazyl

Well-known member
Joined
Nov 9, 2018
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600
Location
Molalla, Oregon
I apologize if this is a duplicate post - I could not find what I wrote this morning.  Thanks to recent questions on this forum I was easily able to drain the water tanks in the RV in preparation for winter.  I also found the water pump, the attached screen/filter, where the water filter is, and where the water line for the ice maker is. 

My question is about refilling the water tanks - as I am preparing for an upcoming trip.

I filled the water tank to 50% (of 86 gallons) and then turned on the water pump.  Air and water spit out but I was unable to get a steady stream.  I waited for ~5 minutes.  I felt air coming out during this time - and I opened but cold and hot water faucets (the hot water heater is 10 gal).

How long is a typical wait for water to come out in a steady stream?

Also, I found the water pump by simply following the noise.  It is next to my wet bay.  In my wet bay I have a valve titled "Bypass valve".  While waiting for the air to get out of the lines, I tried turning this valve in each direction.  The sound of the pump was different in each setting - with one setting sounding like it was pushing nothing but air.  I concluded that this bypass is meant to be turned one way when on city water and another when on potable.  Please let me know if I am correct.  I attached a picture of my wet bay.
 

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If all your lines were empty and also your 10 gallon water heater was empty, it could take upwards to 10 minutes or longer, depending how big you water system is, for everything to fill. Give it some more time. As long as you were getting air out of the lines, you're OK.

As far as the bypass valve, all it does is completely bypass the water heater when in the bypass mode. When it's positioned the other way, it allows cold water to go through the water heater tank and come out hot.

If you were winterizing your RV with pink antifreeze, you'd put that valve in Bypass position so you wouldn't be  putting 10 gallons of antifreeze in the water heater.
 
That's a different Bypass.  The water heater tank winterizing bypass is usually on the rear of the water heater, inside the rig.
 
Yes - some brands of RVs use the word "Bypass" there to mean it bypasses the pump to fill the fresh tank.  Most, though, mark that valve with something more meaningful, e.g. "Fill" vs "Use".
 
Reading earlier posts on this bypass valve had confused me. When I read " bypass" I think water heater bypass, due to my ignorance in knowing how all systems in all rv's work. If I had a tank bypass valve, I would have to get out my P-Touch and label it "water input valve" then label the positions city and tank fill. The OP already knows this apparently, as he was able to put water in the tank. I'm thinking the reason the pump noise changed when he switched the valve was because he started pumping water back to the fill hose. That's just my theory. As far as time to get the air out, that's a big variable. It depends on how big the water heater is, and how much plumbing is in the RV. It also depends on whether or not the low point drains are closed ;D. When I turn on my pump, I generally already have the water heater full, and the system full from city water. To the OP, turn on your pump, open the pressure relief on the water heater, and when water comes out, flip it closed. Then let the pump run until it stops. Then start bleeding the air out of the faucets and shower heads
 
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