Pump Options for Sink Water Pressure

Kayteg1 wrote:


The 12V pump setup is very basic, so there in not much to it and you can buy the cheap pump for about $40.
Planning the trailer, put fresh water tank in front of trailer axle, as that will be filled up most of the time.
When you put gray water behind the axle - You can always drain it, if you notice lack of trailer statibization.

Thanks. This is a two-axle trailer. It's pretty stable. It's built to haul 5500 pounds. Overkill for my needs, but I bought it used for a good deal.

DutchmenSport wrote:

nc_beagle wrote:
... The tank I am looking at says not to use electric pumps. ...

Is the tank you are looking at pressurized? If so, that warning is to prevent an electric (air) pump from pressuring the tank and perhaps, over-pressurizing and blowing it out.

Electric water pumps for RV are just that. They "Pump" the water out of the tank, not pressurize them. Pressurized tanks will then pump their own water, until the pressure drops and then the pump will add air again to pump up the pressure. My parents travel trailer in 1963 worked like this, except the tank was galvanized steel.

Water pumps suck the water out of the tank via a hole at the top of the tank and tube that runs to the bottom of the tank. AND they must be vented, which means there is a second hole for displaced water to be replaced with air. Otherwise, they will form a vacuum and nothing will pump ... well, they might collapse inward with opposite pressure.

So, what type of tank are you looking at. If it says no electric pumps, it's pretty hard to blow out a pressurized tank with a bicycle pump. If its a vented tank, then any RV pump (like the one drawn out in the link above) will work for you. You can get an RV pump that runs on 12 volt battery from anywhere from about $50 to a million dollars if you want. FYI, RV pumps often have a way of adjusting the OUTBOUND water pressure where the pump turns on and off, keeping your water lines pressurized, but NOT the tank.

Also, your tank should have a way to drain it. RV tanks have an outlet on the bottom, attached to a tube running under them, and at the end an open-closed water valve. You open the valve to drain the tank (most important in the winter in snow states).

Hope this helps.

Edit:

Here's a photo of my 35 gallon tank I purchased from TSC (Tractor Supply Company). The pump is an electric water transfer pump which works great for filling my fresh water tank in the camper (both gravity fill on my previous travel trailer, and my current 5er that requires a garden hose attached under pressure.

The only problem is, the pump pumps water OUT of the tank faster than air can be replaced, causing a vacuum even though there is a check-valve (inlet) vent in the middle of the black cap-lid. When the pump runs, the air inlet is not sufficient (it's too small). It wasn't intended to be used with a an electric pump. To get around this, I simply loosen the back lid, or remove it completely when pumping water from the tank with the electric water pump:

I was looking at this one: https://www.etrailer.com/RV-Fresh-Water/Valterra/R8024.html

The 12V pump setup is very basic, so there in not much to it and you can buy the cheap pump for about $40.
Planning the trailer, put fresh water tank in front of trailer axle, as that will be filled up most of the time.
When you put gray water behind the axle - You can always drain it, if you notice lack of trailer statibization.

Whew, you guys are way ahead of me on the experience curve here. I'm not familiar with most of these products. Maybe I should just let you recommend a water setup for me?

I'll have 30 amp service in my 6 x 12 trailer.

In the picture, you can see the sink. I want to put a grey water tank below the drain. My freshwater tank (12 gallon?) would go below the left side bed (the fridge and some storage is also under it. There will be an outlet under there for the fridge that a pump could use. I'd like to put a shower wand to the left of the left bed, but note there is going to be a wall there, so the bed is not exposed to the back doors when they are open.

Several years ago, I converted a cargo trailer. I bought a 15 or 20 gallon tank made for an RV and used a standard water pump, probably a Shur-Flo.
If you have never used a manual water pump, you might be surprised how soon you will want to get rid of it. Been there with a sailboat and a popup.

nc_beagle wrote:
... The tank I am looking at says not to use electric pumps. ...

Is the tank you are looking at pressurized? If so, that warning is to prevent an electric (air) pump from pressuring the tank and perhaps, over-pressurizing and blowing it out.

Electric water pumps for RV are just that. They "Pump" the water out of the tank, not pressurize them. Pressurized tanks will then pump their own water, until the pressure drops and then the pump will add air again to pump up the pressure. My parents travel trailer in 1963 worked like this, except the tank was galvanized steel.

Water pumps suck the water out of the tank via a hole at the top of the tank and tube that runs to the bottom of the tank. AND they must be vented, which means there is a second hole for displaced water to be replaced with air. Otherwise, they will form a vacuum and nothing will pump ... well, they might collapse inward with opposite pressure.

So, what type of tank are you looking at. If it says no electric pumps, it's pretty hard to blow out a pressurized tank with a bicycle pump. If its a vented tank, then any RV pump (like the one drawn out in the link above) will work for you. You can get an RV pump that runs on 12 volt battery from anywhere from about $50 to a million dollars if you want. FYI, RV pumps often have a way of adjusting the OUTBOUND water pressure where the pump turns on and off, keeping your water lines pressurized, but NOT the tank.

Also, your tank should have a way to drain it. RV tanks have an outlet on the bottom, attached to a tube running under them, and at the end an open-closed water valve. You open the valve to drain the tank (most important in the winter in snow states).

Hope this helps.

Edit:

Here's a photo of my 35 gallon tank I purchased from TSC (Tractor Supply Company). The pump is an electric water transfer pump which works great for filling my fresh water tank in the camper (both gravity fill on my previous travel trailer, and my current 5er that requires a garden hose attached under pressure.

The only problem is, the pump pumps water OUT of the tank faster than air can be replaced, causing a vacuum even though there is a check-valve (inlet) vent in the middle of the black cap-lid. When the pump runs, the air inlet is not sufficient (it's too small). It wasn't intended to be used with a an electric pump. To get around this, I simply loosen the back lid, or remove it completely when pumping water from the tank with the electric water pump:

..

3/8" openings/fittings on that tank
RV potable water pumps use 1/2" suction/discharge piping.
Concern would be electric pump could suck faster then Vent can supply....tank collapse??

Seaflo 21 series has 3/8" inlet/outlet but is only 1.2 GPM/35 PSI
Could use 3/8" suction then adaptor to feed 1/2" plumbing system (standard sizing)
Add an accumulator tank and should meet your limited demands
*Sink......outside wand


Seaflo 12VDC 21 Series

I had hand pump on my boat and the 1st modification was to put electric pump on it.
You have to have battery in the trailer for brakes anyway, so putting bigger one for camping should not be a problem.
The tank you link doesn't have drinking water rating?
Years ago I bought bladder Plastimo tank as addition to my bus at the time and still have it 15 years later for another projects.
Other idea might be put 15-20 gallons plastimo tank on upper trailer shelf and have gravity feed.

Thanks for the quick responses. The tank I am looking at says not to use electric pumps. That's why I asked about manual pumps. I do plan to have electricity so I'm not against electric pumps.

Here's the tank: https://www.etrailer.com/RV-Fresh-Water/Valterra/R8024.html