water pump/pressure

BoFuller · Aug 30, 2011

Situation: Travel trailer is temporary living quarters while building (for probably 3 years); just installed a 2600 gallon poly water tank about 100 feet away and probably 5 feet higher than trailer; have water line down to junction box beside trailer; we do have freezing temps in winter; currently I have been filling the 40 gallon tank in the trailer and the pump comes on whenever you turn on the water; living totally off the grid.

Goal: hook up the water line directly to the "city water" connection on the trailer and have running water whenever I turn on the water.

Question: Is there a sensor in the pump that turns it on automatically or is there a small pressure tank somewhere I don't know about. The 40 gallon tank is NOT pressurized.

If I get an identical pump, will it come on automatically, or do I need some kind of pressure tank?

mmurphy · Aug 31, 2011

I do not know what your pump has, but some of the pumps for campers I have seen go by "Bar" pressure,which if I remember correctly is 1 bar =14 psi. They run to that pressure and then quit. Others I have seen are basically a small compressor that pressures a tank with air and also has a pressure on off control.
That sounds like fun trying to get setup to live off of gid. My wife would not beable to handle it, she has to have electricity a spinning the meter as fast as she can!!!

sharpanther · Aug 31, 2011

there are several different set-ups but the easiest way is just getting a shallow well pump set it up with a pressure tank and have a pressure switch. The pressure tank can be outside your 'home' and just connected to the supply in. If you don't have the pressure tank when you use the water the pump will turn on and off too often and that burns them out fast.
You can also set up a continuous run loop and have a shallow well pump running all the time, its a bit more complicated to get the loop right. It also uses a lot more power.
Good luck

Egon · Aug 31, 2011

The RV will most likely just have an on demand pump that shuts off at a preset pressure [usually 30psi] and starts up as soon as water is used. It should be a 12 volt pump.

Ken · Aug 31, 2011

Don't know your brand of camper but there is a point where the the onboard tank and pump outlet and the city water inlet comes to a "T' connection to provide water for use inside camper. usually flexable water line. A suggestion of temperary disconnecting the onboard tank inlet to pump. and attaching the city inlet line to this pump This way the water would run through the pump to maintain pressure.
How is the life at Seligman Ariz. Road finished. House beginning to show results of the labor?
ken

Mickey_Fx · Aug 31, 2011

All I can speak to is what my experiences have been.

As for the pressure tank in an RV, typ it is the hot water tank as there is a captured air "bubble" that serves the purpose of a pressure tank. As an aside, if your water pump turns on instantly when a faucet is opened, that indicated the tank is water logged. Water pumps on an RV typ have a pressure switch built-in and works just like a pressure switch on a well.

Now for hooking up the large water tank to the RV, physically possible but if the only pressure from that water source is gravity, and the only heigth of the water suppy is several ft, supplied pressure from that source is going to be very low (water pressure from gravity is ~.42#/ft). That is not enough to keep the RV pump from operating. You can switch off the pump and live with the very low pressure from the large supply or possibly have to do some re-plumbing so the "city water" feeds the input side of the pump.

Now getting back to the HW tank. To restore the presure tank function, you will need to drain the tank completely to reestablish the air bubble. Preperly restored, you should have 10-15 sec worth of water between on/off cycles of the pump.

Hope this helps

PS
Some RV's are plumbed to reroute the water flow for winter flushing of the sys so there may be some combination of water valve settings that will bypass the pump and the "city water" can flow through the rest of the system. My motorhome doesn't have this so I'm not fully knowledgeable how that set of valves is plumbed into the whole system.