Skip to main content ↑ ↓
Topic: Water Fill While Boondocking/ What is the pump doing with both switches on? (Read 297 times) previous topic - next topic

Water Fill While Boondocking/ What is the pump doing with both switches on?

I am currently using a water bladder with a harbor freight 120v pump to fill the tank while boondocking. The thing is crazy loud, so I'm thinking about getting a second RV pump as both a backup and for this situation. This got me thinking about the two latching relays for water fill and water pump..

When filling, I turn off the pump. If I keep the pump on, the pump just constantly cycles. What is the pump doing in this instance? Is it possible to hookup up a non-pressurized line such as a bladder or container of water and it'll suck the water into the tank? I don't want to try it out and burn out my pump, but it'd be a better alternative than having to use this loud HF pump.
1999 U320 WTFE #5586
2014 Subaru Forester 6sp
4000 watts of solar
650 aH @ 24v

Re: Water Fill While Boondocking/ What is the pump doing with both switches on?

Reply #1 –
Lots of us went with a Quick Fill upgrade to our fresh water tanks, makes life a lot easier and faster fills. Add a spare water pump to your inventory of spare parts and you have a great set up for boondocking.

What did you do to your coach today VII
Doug W.
96 36' U270 CSGI #4946
04 Toyota Tacoma 4x4
PNW

Re: Water Fill While Boondocking/ What is the pump doing with both switches on?

Reply #2 –
Quote from: Zach –
When filling, I turn off the pump. If I keep the pump on, the pump just constantly cycles. What is the pump doing in this instance?
If your newer coach works the same as our older model, turning on the water pump when filling the fresh water tank does nothing except (as you have observed) running the pump continuously.  Basically, you are pumping the water in a closed loop.  The water pump sucks the water out of the (coach) water tank and then pumps it through the open fill valve back into the tank.  If, while doing this, you try turning on a water faucet in the coach you will observe little or no water pressure.

And no, I don't think it would suck water out of a external bladder to fill the tank.  Unless...you could install a "T" in the water line between the coach fresh water tank and your water pump inlet.  Run a hose from the "T" to your water bladder.  Close the valve between the fresh water tank and the "T".  Then your water pump would suck water out of the bladder and it should fill your coach water tank.  See drawing below.

Or do as Doug suggests (above).


1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Water Fill While Boondocking/ What is the pump doing with both switches on?

Reply #3 –
Quote from: Chuck & Jeannie –
If your newer coach works the same as our older model, turning on the water pump when filling the fresh water tank does nothing except (as you have observed) running the pump continuously.  Basically, you are pumping the water in a closed loop.  The water pump sucks the water out of the (coach) water tank and then pumps it through the open fill valve back into the tank.  If, while doing this, you try turning on a water faucet in the coach you will observe little or no water pressure.

And no, I don't think it would suck water out of a external bladder to fill the tank.  Unless...you could install a "T" in the water line between the coach fresh water tank and your water pump inlet.  Run a hose from the "T" to your water bladder.  Close the valve between the fresh water tank and the "T".  Then your water pump would suck water out of the bladder and it should fill your coach water tank.

Or do as Doug suggests.  Much simpler.

I figured as much. I thought it may be a cheap workaround as I think some RVs these days allow you to fill using the existing water pump. I'll likely just purchase a new 12v pump that I can use as a backup. I may try Doug's suggestion eventually as well.
1999 U320 WTFE #5586
2014 Subaru Forester 6sp
4000 watts of solar
650 aH @ 24v