add pump to city water supply side?

JustinChase · 09-21-2018, 10:55 AM

I've come to discover that the water pressure pump only works in my RV from the water tank, not from city water.

I'm living full time where I have a continuous supply of spring water, and would prefer to just have the RV connected to this, versus filling the tank and using that system. However, the spring water supply has very little pressure, and I'd like to boost that.

Is it possible and practical to add a pump to the city water supply instead of only having pressure when using the tank.

Also, the tank pressure pump doesn't add very much pressure, and showers still suck. is there a limit to how much pressure RV plumbing can handle? It appears the RV is plumbed with Pex, which should handle at least 50 lbs of pressure fine (it does in my house). I have no problem replacing fixtures if necessary.

Thoughts?

fjr vfr · 09-24-2018, 11:26 AM

I would work on increasing the pressure from the spring water supply and not ad anything except a pressure regulator to the RV. Normal pressure is 40-45 psi. You can adjust the regulator to keep it in this range.

JustinChase · 09-24-2018, 01:29 PM

Thanks, but the spring is gravity fed. There is no easy way to increase that pressure, nor do I want to. I'm stationary at this site for the foreseeable future, so increasing the pressure inside the RV is the only method of getting good pressure that makes sense at this time.

I can't see how/where the RV system splits or determines whether or not to feed water to faucets from city or tank, so I'm not sure where to move pump to pressurize entire system, or if that's even possible.

Pathfinder75 · 09-24-2018, 06:52 PM

I'm assuming you have a hose or pipe coming from spring. If so I would find a pump (RV or Home well pump) to hook this supply line to then using a well acummulator tank with line running from pump to tank. This will supply water same as a country home with a well. Hook trailer city connection to Accumulator tank. Not knowing where you are you may need to build a dog house to contain pump and tank to insulate from freezing weather.

This would leave trailer system alone and supply a real water source if you used a quality water pump such as a home well pump.

A simplier answer would be get another $50 RV pump and hook up between trailers city port and spring hose so you can pump it. This would be similar to your tank pump unless you bought a more powerful pump.

elliott-maine · 09-24-2018, 07:10 PM

How much head do you have at the spring? Does it just reach the tank fill on the trailer, or is it higher than the trailer? If it is high enough, you can put a barrel or tank and let the spring fill it and run a hose from the tank to your city water fill.

JustinChase · 09-24-2018, 07:31 PM

All fine ideas, but not at all what I want.

I want to move the pressure pump to pressurize ALL water in the RV, no matter the source.

I don't want to buy another tank, build a structure to protect it, or any other of what has been suggested as a work around.

I just want to add or move a pump, inside and installed to the RV to give consistent pressure always.

I don't know how the system knows to pressure the tank but not the city water, but will provide water without my input no matter the source.

In other words, I'm not sure where to move the pump to do what I want, or why it's not this way by default.

SrFox · 09-24-2018, 08:31 PM

Just use the low pressure to fill your RV tank and then use the tank. The tank is not pressurized, the pump pulls water from the tank then pressurizes it in the pipes.
This is the low tech solution and costs nothing.
If you are more technical, you could add a pump to the city water connection I suppose then run the pump when you open the tap. You would have to splice the pump into the city water source inside your rv bay.

JustinChase · 09-24-2018, 10:29 PM

Quote:

Originally Posted by SrFox

Just use the low pressure to fill your RV tank and then use the tank. The tank is not pressurized, the pump pulls water from the tank then pressurizes it in the pipes.
This is the low tech solution and costs nothing.
If you are more technical, you could add a pump to the city water connection I suppose then run the pump when you open the tap. You would have to splice the pump into the city water source inside your rv bay.

Fill the tank in order to use the pump is how I'm operating now. It works, but I'm sure there will come a day when that tank runs dry and it's either freezing, raining hard, or some other miserable condition outside when I have to go refill the tank, and I'll be thoroughly unhappy.

Moving the pump to work on the city water would avoid this.

I don't yet know/understand how the RV automatically uses water from city supply when connected, or tank when city is not connected. Once I understand this, I can probably figure out where to put the pump to pressurize everything.

I have yet to see a downside to this change, as long as the inlet pressure isn't too high, which a regulator would resolve.

Using the tank would/will help keep me aware of when the gray/black tanks are getting full, but I'm not sure it's worth running that way, for that reason alone.

OneReallyOldGuy · 09-25-2018, 09:37 AM

Recently I stayed at a campground with low water pressure. The shower was adequate but the kitchen sink was barely more than a trickle. I filled my fresh water tank and whenever I washed dishes I simply turned on my water pump. It boosted my water pressure and drained my tank over time even though I was still hooked up to the city water supply.
It worked out well and I have adopted a regimen of turning on the pump every now and then to empty my fresh tank and then I add water back into my tank. That way my fresh water tank always has “fresh” water in it.
If you have low pressure even when using your pump you may have a clogged whole house water filter or a bad pump.

SrFox · 09-25-2018, 11:11 AM

Quote:

Originally Posted by JustinChase

I don't yet know/understand how the RV automatically uses water from city supply when connected, or tank when city is not connected. Once I understand this, I can probably figure out where to put the pump to pressurize everything.

The pump only draws water from the tank, not from the outside water. I suppose you could T into the fresh water line but you would have to install a check valve between the T in the fresh water and the tank so you would not be filling the tank when you have it hooked to city water. In this way your pump should come on whenever your pressure is less than the minimum pressure your pump is set to.
Make sense?

SrFox · 09-25-2018, 11:27 AM

elliott-maine · 09-25-2018, 11:27 AM

There is a backflow preventor in the pressure side of your pump that stops the city water from going back through pump into your tank. This will sometimes stick and allow the city water to fill your tank. Increasing the pressure in the system could cause this to stick or fail. The pump draws water from your tank, and the city water is essentially a separate system util after the pump. If you T into the line before the pump, you need to have a shut off valve on the line from the tank or it will fill constantly. You can accomplish your goal either by doing that, or adding a separate pump for the city water line from your spring.

PEX will take more pressure than you will ever use. However, the fittings used on an RV are not the best, and some are made of plastic. This is your weak link. To get a better shower, replace your shower head with an Oxygenics or similar shower head. By inducing air into the shower hose, you get an apparent increased pressure and flow while using no more water. RVs shoud be delivered with one of these.

If you need a sketch of what you can do, let me know.

SrFox · 09-25-2018, 11:28 AM

I tried to post a graphic but for some reason it is not working. Here is a link to the image in my Dropbox
https://www.dropbox.com/s/knx38yb4wu...ookup.jpg?dl=0

elliott-maine · 09-25-2018, 12:33 PM

A check valve would not work as the pump's suction would probably not open it when you need to use the tank. You really need a manual valve that will only allow one source to be drawn on at a time.

SrFox · 09-25-2018, 07:58 PM

The pump has about 45 pounds of pressure so I am sure it would have enough suction open the check valve. Check valves normally only have one or two pounds on pressure as it is the back pressure of the water that keeps it closed. You would however have to cap the water main line in if you were not hooked up to city water.

JustinChase · 09-27-2018, 05:35 PM

Quote:

Originally Posted by SrFox

The pump only draws water from the tank, not from the outside water. I suppose you could T into the fresh water line but you would have to install a check valve between the T in the fresh water and the tank so you would not be filling the tank when you have it hooked to city water. In this way your pump should come on whenever your pressure is less than the minimum pressure your pump is set to.
Make sense?

That makes sense, i think, but I still don't understand how the RV "knows" to use the tank when there is no city hooked up, but use the city supply when it is.

Is there some pressure switch, or other system that makes this possible/work?

I've just discovered that when they re-plumbed my RV they didn't bother with individual shut off valves at the various fixtures, so I have to find main shut off valves to replace the bathroom sink fixture. they also did a terrible job of running the pex, so I'll end up just re-plumbing it again.

When I get around to this, i'd like to get the pump to pressure everything. I have found a place where it seems the cold water is connected to the hot water line, which seems odd, but I've often heard RV's are weirdly plumbed anyway, so maybe this is normal for an RV.

Is there an online resource for 'normal' RV plumbing so i can understand how it was done from the factory? I don't want to plumb it like a house if that will cause me problems.

Appreciate any help understanding and planning this project.

elliott-maine · 09-27-2018, 06:38 PM

If you leave the pump on all the time, the city water pressure is such that the check valve after the pump will stay closed, so the pump will not run. Once the city water is turned off, the check valve after the pump will not have the back pressure and will draw from the tank.

We only turn on the pump when we are hooked up to the city water.

Very few RVs have independent valves for each fixture, so you will have to shut off the water at the city water connection and shut off the pump. The best thing to do is to then open your low point drains and crack one of the fixtures, both hot and cold, to drain the water to the lines. The hot line connected to the cold may be a red PEX that runs to the hot water heater. By making this red, you can therefore trace the entire hot water system.

JustinChase · 09-27-2018, 08:24 PM

Quote:

Originally Posted by elliott-maine

If you leave the pump on all the time, the city water pressure is such that the check valve after the pump will stay closed, so the pump will not run. Once the city water is turned off, the check valve after the pump will not have the back pressure and will draw from the tank.

We only turn on the pump when we are hooked up to the city water.

Very few RVs have independent valves for each fixture, so you will have to shut off the water at the city water connection and shut off the pump. The best thing to do is to then open your low point drains and crack one of the fixtures, both hot and cold, to drain the water to the lines. The hot line connected to the cold may be a red PEX that runs to the hot water heater. By making this red, you can therefore trace the entire hot water system.

In my head, I'm thinking the tank and city water both come into a Tee, and that Tee then goes to the pump, then onto the RV water system. A check valve would be installed between the tank and the tee, to prevent the tank being filled from the city water supply.

The city water is my spring and has maybe 5-10 psi (just a guess, but very minimal). I'm hoping that by changing the system in this way, anytime a faucet in the RV calls for water, it will cause the pump to engage, pressurizing the system, as long as the pump is turned on, which it will always be.

If I ever move it from here, I'll need to install a regulator on the city water supply, but not necessary now.

as for the Pex, they ran everything in white, which is super not helpful.

I've marked up this photo to show the cold water (supply) in blue going to the water heater, and the hot in red coming from the water heater.

I have no idea what that fitting in the middle is, nor why it appears the cold flows into the hot water lines.

It seems all jacked up to me, but I do get warm water out of the tap, but I would not call it hot. it also doesn't seem to maintain temp.

Should I try to maintain this mess, or just run it like a normal person in a normal house?

I'm strongly considering just adding a water manifold and running home runs of both hot and cold to each fixture, since I need to re-plumb everything anyway.

I just can't help but think it's done this way for a reason, but I'm at a loss to come up with such a reason.

SrFox · 09-27-2018, 08:27 PM

If I turn on my pump, it only pulls water from the holding tank, even if I have city water connected and on.

Regarding the "standard" plumbing for RVs, I doubt there is one.

**wingnut60** · 09-28-2018, 01:35 PM

If you are asking about the item in the pic with the 'what is this' arrow--it is a mixing valve. Sometimes, the water heaters provide water that is too hot, and the valve is used to add some cold water to the hot water when in use.
Or, since I can't see the rest of the line directions, could be a bypass valve to winterize the trailer without going thru the water heater.