All new plumbing...

[malconium]

I am working on the re-design of my plumbing system for my 1973 31' remodel. I am having to start pretty much from scratch since my unit was largely gutted when I got it. I am still using the fresh water tank and the kitchen sink but not much else. Actually that does not seem to be a bad thing since there are various new things that I want to incorporate in the system that were not available in 1973. In particular I will be using a modern fresh water pump and PEX tubing instead of the copper that was originally installed. I have a copy of the 1973 service manual and I have seen some parts of the old plumbing before I took out what was left of it. Based on what I have seen of the old, what I see in the service manual and what I think is needed I have come up with some questions that I would appreciate finding some answers to as follows:

1.) What prevents water from the city water input from back flowing into and overflowing the fresh water tank? As near as I can tell in my original plumbing layout the water pump must have performed that function. Was that the case and does a modern water pump do that too?

2.) I see that the original layout had a water purifier on just the cold water side of the kitchen sink. I would like to have a water purifier for more than just my cold water. The trick is that city water comes into my floor plan at the street-side rear corner while the fresh water tank and pump will be near the entrance door. In the original layout the city water daisy chained its way along from the input to the water heater, past the bathroom and finally over to the kitchen sink area where the water pump is located. It looks like if I wanted to use a single filter for both the fresh water tank and city water that I would have to run my city water over to the kitchen sink area first. I would need to connect it to a point just past the water pump from the fresh water tank and then add the filter just past that point. I guess the other option would be to use several smaller point of use water filters. What are other forum members doing with this problem?

3.) It looks like there were no water shut off valves near the various sinks and faucets. This is probably reasonable since it is pretty easy to turn off the water flow to the whole system if something needs to be repaired. Since I am re-doing the plumbing from scratch though it would be easy enough to add water shut off valves under the sinks and etc. I can get PEX compatible valves that have the right type of adapter on their output ends for easy connection to the faucets. If I don't use valves I will at least need some type of fitting on the end of the PEX line. What do you think

4.) I have added new 32 gallon holding tanks both of which are under the floor. My intention is to use a macerator pump to drain both of them. Both of the tanks are set up with 1-1/2 inch drains specifically with this in mind. What I am intending to do is to connect from the output of the gray tank through a waste valve and then through a one-way valve that I found at Home Depot to the output side of the black tank and its waste valve. The macerator pump will be connected to this common point. My thought is that the macerator pump should be able to create enough suction to open the one-way valve to the gray tank if the waste valve on the gray tank is open. Also I thought that if my gray tank was too full and the black had space that if I opened both of the waste valves that the water level in the two tanks would seek to reach the same level. Does this all sound like it should work?

By the way I will try to post some photos of what I have already done soon and post photos of the rest of the plumbing as it progresses. I am sure I will have some more questions too as things progress.

Thanks,

Malcolm

[markdoane]

Malcolm,

3.) I would leave the valves off. As you pointed out, you can easily turn off the pump if you need to change a faucet. Valves are expensive, they also require another crimped connection in a difficult location. You can purchase swivel faucet adapters that go from pex to straight pipe thread.

4.) I think your waste line will work as planned. Keep the line from the black tank to the macerator as straight as possible, any lumpy stuff will flow best in a straight run. The one way valve should work fine as long as you don't let any carrot peels or pickle chips in the gray tank. You will need a valve on the outlet of the macerator pump also. Macerator pumps can let a little water pass through, even when they are not running.

[Minno]

Malcolm,

Some thoughts on each:

1.) A check valve (aka backflow preventer) is what prevents city water from flowing backwards through the pump and into the water tank. Most new water pumps have a built-in check valve I think, but double check to make sure one is included. You can always one to the output water line of the pump as well.

1a) You should think about installing a pressure reducer on the inside of the city water inlet. Last thing you want is for a high pressure city water supply at a campground blowing apart your fresh water lines, seals, pump, etc. You can always use a portable one that you connect to the faucet instead of installing a permanent one. Personal preference as to what you want to use.

2.) Depends on what you want filtered. If you want everything filtered, then you have the options pretty well identified. Running another cold water line the length of the trailer so you can have one filter is not really that big a deal. If you really only want the kitchen sink cold water filtered for cooking, making coffee, etc, then you can get by with installing the filter into the cold water supply to the kitchen sink. Another option is to use an external filter, so the water is filtered before it enters your trailer. This is what we currently do with our SOB trailer. I never filter the water I fill up the tank with at home, but we do use it when we connect to city water at campgrounds and when I fill up the water tank on the road.

3.) I agree – shut off valves at each faucet is overkill in an rv.

4.) Interesting – do you have pictures of the new holding tanks in place? Where did you get them? I'm looking for a gray water tank for Little Girl.

I am a tad concerned with only having a 1 ½ drain out of the black tank though. Typically, that’s a 3 inch drain, and for a good reason. Not sure how much suction the macerator pump will generate, but you might be setting yourself up for clogage using just a 1 ½ drain on the black water tank.

Chris

[azflycaster]

#4 Why not just have a standard dump hose connector on each tank with it's own valve. You could use a portable pump with a hose connection on each or just dump at a dump station if you want to. With your setup you could only dump your gray water by dumping the black. That would not be convenient if you were boondocking. I can also see problems with a one way valve between the tanks getting jammed with stuff that goes down the sink.

32 gallon tanks sound great, that is a major upgrade from the tiny tanks of the 70s.

[Aage]

Originally Posted by malconium

4.) I have added new 32 gallon holding tanks both of which are under the floor.

Malcom,

That's an amazing size of tank you used there! My '74 has a ten gallon grey tank, in comparison. It sounds like you have already installed them.

Any chance to took some photos of where they sit in the trailer?

Thanks,
Aage

[malconium]

The following thread has some information about where I got my holding tanks in post #5. I think I got a tremendous deal on them for $151 each with free shipping. Take a look. Also in that same post I have a link to a detail as to how I am going to change my belly pan in the area where my axles are to be below the axles to give me more holding tank room.

http://www.airforums.com/forums/f444...ank-54087.html

I saw that the tank link was broken so I added a new note to the bottom of that thread. The correct link to tank source is:

Holding Tank : Holding Tanks : RV Holding Tanks : Black Water Tank : Waste Holding Tank : RV Tanks : Black Water Tanks : Gray Water Tank : Grey Water Tank - Icon Technologies Limited

I also see that I must have bought at the right time. The pricing has gone up some. You can also get a version of the same tank with a pre-installed 3" drain. I wanted to go with the smaller drain so I installed my own fittings.

I installed the two tanks in the floor cavities just behind and just in front of the rear axle. The black tank is the rear one and the gray tank is the front one. In the above thread I thought I was going to have to add an intentional dent to the front tank to clear the axle but it looks like I am going to just fit. The lowest part of the tank is actually not where the axle crosses over.

I am going to post some photos of the tanks. If you look close you should be able to see the following details:

1.) Aluminum angle along the edges of the tanks bolted up to the floor to support the tank flanges. By the way I only had to saw off about 1/2" total on the side flanges to get the tanks to fit in the cavities.

2.) Backup nylon strapping to help support the tanks. I am not sure that this is at all necessary since the top flanges seem plenty sturdy but I decided not to take a chance. These are straps that I bought in a four pack at Home Depot and only used two. The hooks are attached to eye bolts at the ends. In the middle I put a piece of PEX tubing which I slit and put over the middle frame rail.

3.) My dump flanges are 1-1/2" pipe as I mentioned above. You can also see the tank monitoring probes next to the dump openings. The tanks came without any flanges attached and I bought the flanges and installed them separately. The tanks and flanges are all ABS so regular ABS cement works fine.

4.) You will see where I glued flanges to the top of the tank for the toilet and the other drain connections.

Please let me know if you have any questions about what I did.

Malcolm

[malconium]

Actually in my proposed drain arrangement with the macerator pump I will be able to dump gray water separately from the black water if I want to. Check out the attached sketch. To drain just the gray water I would open the valve on the gray tank, leave the valve on the black tank closed and open the dump valve that bypasses the macerator pump. I the main idea of the one-way valve is to prevent black water from working its way into the gray water tank. Also I thought that letting some gray water flow over to the black water tank would help break down solids and make pumping them out easier. The one thing that I can not do in my current tank placement is to put the macerator directly in line with the black holding tank. I do have a rubber Y that angles the black water output toward the pump that I hope will help with the over all flow.

Malcolm

[malconium]

I was able to complete the hook up of both the kitchen sink drain and the drain for the bathroom sink. I am re-using the original kitchen sink since it seemed to be in good shape - just needs some cleaning. I had a little trouble finding new strainers for the kitchen sink but finally found them in the section of Home Depot that carries bar sink related fittings. One of the photos shows them. The bathroom sink is a cute little oval stainless sink that I bought from the following RV supply store which happens to be local to me but does sell on the Internet. I think it might be this one but I thought I paid less than that amount. If anyone is seriously interested let me know and I will check the part number.

RV PARTS OUTLET

The attached photos should show pretty much all of the drains except for the under the floor part of the shower drain. Check out the really cool retro boomerang formica and the metal counter edging. The faucets that I picked were all in stock at Home Depot. As you can see in the photos I have not finished hooking up the faucets yet and the one for the kitchen is still in the box.

Malcolm

[Silverflames]

Originally Posted by malconium

The following thread has some information about where I got my holding tanks in post #5. I think I got a tremendous deal on them for $151 each with free shipping. Take a look. Also in that same post I have a link to a detail as to how I am going to change my belly pan in the area where my axles are to be below the axles to give me more holding tank room.

http://www.airforums.com/forums/f444...ank-54087.html

I saw that the tank link was broken so I added a new note to the bottom of that thread. The correct link to tank source is:

Holding Tank : Holding Tanks : RV Holding Tanks : Black Water Tank : Waste Holding Tank : RV Tanks : Black Water Tanks : Gray Water Tank : Grey Water Tank - Icon Technologies Limited

I also see that I must have bought at the right time. The pricing has gone up some. You can also get a version of the same tank with a pre-installed 3" drain. I wanted to go with the smaller drain so I installed my own fittings.

I installed the two tanks in the floor cavities just behind and just in front of the rear axle. The black tank is the rear one and the gray tank is the front one. In the above thread I thought I was going to have to add an intentional dent to the front tank to clear the axle but it looks like I am going to just fit. The lowest part of the tank is actually not where the axle crosses over.

I am going to post some photos of the tanks. If you look close you should be able to see the following details:

1.) Aluminum angle along the edges of the tanks bolted up to the floor to support the tank flanges. By the way I only had to saw off about 1/2" total on the side flanges to get the tanks to fit in the cavities.

2.) Backup nylon strapping to help support the tanks. I am not sure that this is at all necessary since the top flanges seem plenty sturdy but I decided not to take a chance. These are straps that I bought in a four pack at Home Depot and only used two. The hooks are attached to eye bolts at the ends. In the middle I put a piece of PEX tubing which I slit and put over the middle frame rail.

3.) My dump flanges are 1-1/2" pipe as I mentioned above. You can also see the tank monitoring probes next to the dump openings. The tanks came without any flanges attached and I bought the flanges and installed them separately. The tanks and flanges are all ABS so regular ABS cement works fine.

4.) You will see where I glued flanges to the top of the tank for the toilet and the other drain connections.

Please let me know if you have any questions about what I did.

Malcolm

Great looking work. Did you have any problems hooking up the drain lines comming down? Did the drain line clear the frame? I'm looking to do the same job, and my frame seems to have about a 58" space for the tank to sit in. Was it enough room for a 90 elbow to go back down tword the back tank? Or should I ask who did you set up the discharge?

[malconium]

It was a little tight to fit things in but I was able to do so. One thing that helped was that I used 2" ABS - or was it 1-1/2"? I have a macerator pump on the output end so it can draw fluid through the smaller pipe. The black tank is behind the gray tank. If I were to do it again I think I would make a larger connection from the black tank back to the pump which could handle a 3" input line. The attached photo shows how I was able to get under the rear axle. I had originally hoped to be able to go over this axle but there just was not enough room. The item on the right side is a one-way valve that keeps fluid from being able to flow from the black water tank back to the gray water tank. Notice also that there is a clean out cap on the bottom of the pipe. If you look closely you can barely see the remote control slide valve that I used on the output of the gray tank. I used one on each of the tank outputs.

I would be happy to try to answer any other questions you might have.

Malcolm