# Adding Water Pressure Tank



## Wisconsin-Knight

I think somewhere on this forum I mentioned that I was adding a pressure tank to my 2005 21RS. I have completed that and thought I would illustrate the completed project. I purchased a Little Giant 5 gal. pressure tank from Amazon and found it would fit under the couch without having to raise the couch. It came with a 3/4 inch stainless pipe for a connection and the literature insisted that a 75 psi relief valve be installed for safety or the warranty would be void. I found I could purchase a stainless relief valve preset at 75 psi on eBay for $17.00 delivered so I opted to install one even though I have a pressure regulator at the inlet to the trailer set at around 50 lbs. This valve came with a 3/4 inch inlet and a 1/2 inch outlet. I thus decided to use a pipe "cross" and purchased a 3/4 inch cross. I found that stainless was about the same price as brass, so I chose stainless. The "cross" fit the tank and the pressure relief valve and a couple reducing nipples allowed for the connection to the pump and the line to the trailer. The flexible hose will decouple any vibration from the pump and a couple 45 degree "street ells" finished the project. This is an elegant, but perhaps overly expensive way to do this. A threaded 3/4 inch schedule 80 PVC tee and a 1/2 inch tee and a couple nipples would have perhaps been less than 1/2 the cost. Nevertheless, this installation is pretty straight forward and when I get to Florida, I'll get to try it out. I think it will add some zip to the output of the faucets because I suspect that the flow is limited by the pump capacity, not the trailer plumbing. It will also stop the pump turning on every time I flush the toilet in the middle of the night. The hose from the pump to the cross looks like it is braided stainless, but it is just plastic with an internal braid.

Rowland


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## Insomniak

Wisconsin-Knight said:


> I think somewhere on this forum I mentioned that I was adding a pressure tank to my 2005 21RS. I have completed that and thought I would illustrate the completed project. I purchased a Little Giant 5 gal. pressure tank from Amazon and found it would fit under the couch without having to raise the couch. It came with a 3/4 inch stainless pipe for a connection and the literature insisted that a 75 psi relief valve be installed for safety or the warranty would be void. I found I could purchase a stainless relief valve preset at 75 psi on eBay for $17.00 delivered so I opted to install one even though I have a pressure regulator at the inlet to the trailer set at around 50 lbs. This valve came with a 3/4 inch inlet and a 1/2 inch outlet. I thus decided to use a pipe "cross" and purchased a 3/4 inch cross. I found that stainless was about the same price as brass, so I chose stainless. The "cross" fit the tank and the pressure relief valve and a couple reducing nipples allowed for the connection to the pump and the line to the trailer. The flexible hose will decouple any vibration from the pump and a couple 45 degree "street ells" finished the project. This is an elegant, but perhaps overly expensive way to do this. A threaded 3/4 inch schedule 80 PVC tee and a 1/2 inch tee and a couple nipples would have perhaps been less than 1/2 the cost. Nevertheless, this installation is pretty straight forward and when I get to Florida, I'll get to try it out. I think it will add some zip to the output of the faucets because I suspect that the flow is limited by the pump capacity, not the trailer plumbing. It will also stop the pump turning on every time I flush the toilet in the middle of the night.
> 
> Rowland


There's an inlet and an outlet? I can only see one connection for the water where your tee is connected, and the air valve. Is this one different in some way since I believe it's intended for well-water use?


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## Wisconsin-Knight

Insomniak said:


> I think somewhere on this forum I mentioned that I was adding a pressure tank to my 2005 21RS. I have completed that and thought I would illustrate the completed project. I purchased a Little Giant 5 gal. pressure tank from Amazon and found it would fit under the couch without having to raise the couch. It came with a 3/4 inch stainless pipe for a connection and the literature insisted that a 75 psi relief valve be installed for safety or the warranty would be void. I found I could purchase a stainless relief valve preset at 75 psi on eBay for $17.00 delivered so I opted to install one even though I have a pressure regulator at the inlet to the trailer set at around 50 lbs. This valve came with a 3/4 inch inlet and a 1/2 inch outlet. I thus decided to use a pipe "cross" and purchased a 3/4 inch cross. I found that stainless was about the same price as brass, so I chose stainless. The "cross" fit the tank and the pressure relief valve and a couple reducing nipples allowed for the connection to the pump and the line to the trailer. The flexible hose will decouple any vibration from the pump and a couple 45 degree "street ells" finished the project. This is an elegant, but perhaps overly expensive way to do this. A threaded 3/4 inch schedule 80 PVC tee and a 1/2 inch tee and a couple nipples would have perhaps been less than 1/2 the cost. Nevertheless, this installation is pretty straight forward and when I get to Florida, I'll get to try it out. I think it will add some zip to the output of the faucets because I suspect that the flow is limited by the pump capacity, not the trailer plumbing. It will also stop the pump turning on every time I flush the toilet in the middle of the night.
> 
> Rowland


There's an inlet and an outlet? I can only see one connection for the water where your tee is connected, and the air valve. Is this one different in some way since I believe it's intended for well-water use?
[/quote]

Insomniak, The tank is for well water use, that is the type pressure tank you really want, not a hot water expansion tank according to the manufacturer. There is only one connection to either type tank, water flows into the tank and compresses a diaphram. When water is turned on, water flows back out of the tank into the system through the connection from which it entered the tank. I originally purchased a hot water expansion tank, but when I called the manufacturer to see if I could run it on it's side, they said no and that what I really wanted was a horizontal well water pressure tank. The hot water expansion tank was going to cost me $36.00 on Amazon, plus about $20.00 shipping.
The horizontal tank was about $73.00 with free shipping from Amazon, so the difference was not that great. The expansion tank came from a different source and there was no free shipping. The trick is to do this yourself and you save so much on labor that cost of parts is nominal.
Rowland


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## cdn campers

Hi i have a question about your mod, how does it work, does it put pressure behind the water ie store water pressure in the tank and then push it through the trailer when you open a tap.


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## Insomniak

cdn campers said:


> Hi i have a question about your mod, how does it work, does it put pressure behind the water ie store water pressure in the tank and then push it through the trailer when you open a tap.


Yep,that's how they work. The tank has a rubber bladder that is under pressure. Look to the left side of the photo and you'll see the blue air valve. You usually set the air pressure to a couple psi less than the turn-on pressure of the water pump. This allows you to use a few gallons of water without the pump kicking on, or you can even turn the pump off and still flush in the middle of the night. It also evens out the flow of water when showering using the water pump - no more "high-flow / low flow" cycling from the pump. I've done this mod on the four trailers we've owned, but I haven't seen a well water tank used before. I didn't even know they existed in this size....


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## Wisconsin-Knight

Insomniak said:


> Hi i have a question about your mod, how does it work, does it put pressure behind the water ie store water pressure in the tank and then push it through the trailer when you open a tap.


Yep,that's how they work. The tank has a rubber bladder that is under pressure. Look to the left side of the photo and you'll see the blue air valve. You usually set the air pressure to a couple psi less than the turn-on pressure of the water pump. This allows you to use a few gallons of water without the pump kicking on, or you can even turn the pump off and still flush in the middle of the night. It also evens out the flow of water when showering using the water pump - no more "high-flow / low flow" cycling from the pump. I've done this mod on the four trailers we've owned, but I haven't seen a well water tank used before. I didn't even know they existed in this size....
[/quote]

Insomniak,

Very good response. The manufacturer's suggested list on these is generally around $170.00. At $73.00, Amazon is really discounting them. Presumably the bladder is shaped differently for operation as a horizontal tank. If you have room for a vertical tank, I think a water heater expansion tank would probably work fine. Especially if you plumb it in with the water connection at the top as Insomniak reported he has done in the past. I just finished installing another tee with a pressure gauge so I can determine the turn on pressure and adjust the pressure in the tank to a couple pounds less than the turn on pressure.

Rowland
PS: I just saw Saskatoon up there. I used to manufacture parts for mass spectrometers in my home and I had a customer in Saskatoon. That was 40 years ago and I loved typing Saskatoon, Saskatchewan. What a name! That was before word processors and computers.


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## CamperAndy

Wisconsin-Knight said:


> Presumably the bladder is shaped differently for operation as a horizontal tank. If you have room for a vertical tank, I think a water heater expansion tank would probably work fine. Especially if you plumb it in with the water connection at the top as Insomniak reported he has done in the past.


Water heater expansion tanks will not work for your trailer unless all you want is to dampen the water hammer from the pump. It will store very little water for use without the pump. You need a bladder in the tank to store the energy to push the water into the system.


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## Oregon_Camper

Here is a link to my site with 2 pictures of how I installed the tank in our previous 28RSS

http://home.comcast.net/~tannerjim1/Mods/accumulator_tank.htm


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## Insomniak

CamperAndy said:


> Presumably the bladder is shaped differently for operation as a horizontal tank. If you have room for a vertical tank, I think a water heater expansion tank would probably work fine. Especially if you plumb it in with the water connection at the top as Insomniak reported he has done in the past.


Water heater expansion tanks will not work for your trailer unless all you want is to dampen the water hammer from the pump. It will store very little water for use without the pump. You need a bladder in the tank to store the energy to push the water into the system.
[/quote]
The water heater expansion tanks have a bladder and air valve. The five gallon tank with pressure aet at about 22 psi holds a few gallons of water - more than enough to make it through the night.


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## CamperAndy

Insomniak said:


> Presumably the bladder is shaped differently for operation as a horizontal tank. If you have room for a vertical tank, I think a water heater expansion tank would probably work fine. Especially if you plumb it in with the water connection at the top as Insomniak reported he has done in the past.


Water heater expansion tanks will not work for your trailer unless all you want is to dampen the water hammer from the pump. It will store very little water for use without the pump. You need a bladder in the tank to store the energy to push the water into the system.
[/quote]
The water heater expansion tanks have a bladder and air valve. The five gallon tank with pressure aet at about 22 psi holds a few gallons of water - more than enough to make it through the night.
[/quote]

I am aware of the use of the tank (I installed a 5 gallon one in my trailer) but be careful purchasing these tanks. I guess I should have said "Not all water heater expansion tanks have bladders or bladders that you can adjust the pressure on." I purchased one that was listed as a well pump accumulator tank, I set the pressure in the bladder to 1 psi above the turn on pressure of the pump.


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## Insomniak

I think I will re-install the accumulator tank in our 301 this weekend. We rarely dry camp anymore, but the water hammer from the new toilet that Gilligan is using now is pretty bad. The problem may be the toilet itself, but I guess I'll find out. Already tried a pressure reducer at the water inlet, and that helped a bit, but you still get a "bang" when you let up on the pedal after a flush.


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