Water System Plan - Van de Kamp

[akadaedalus]

My freshwater tank will be in the van interior and I'm thinking I'll take the upper .5" NPT port and put a tee in it to a) an overflow drain through the floor and b) a vent that curves a little bit and comes out through a vented hole in the wall. I debated just doing the overflow but don't want a siphon effect either (although I don't know how the siphon would happen if I don't run a tube into the tank). The wife does NOT want me to go to the roof and I don't want to either, and she also does not want me to hide it in the wall in case it has a disastrous problem.

If my freshwater tank smells bad, that's something I'll want to deal with sooner rather than later.

edit: it seems the recent conversation is about grey tank venting. I'll cross that bridge when I get there. I was only asking about the dip tube. Sorry about necroing the venting thread.

 

[marklg]

My freshwater tank will be in the van interior and I'm thinking I'll take the upper .5" NPT port and put a tee in it to a) an overflow drain through the floor and b) a vent that curves a little bit and comes out through a vented hole in the wall. I debated just doing the overflow but don't want a siphon effect either (although I don't know how the siphon would happen if I don't run a tube into the tank). The wife does NOT want me to go to the roof and I don't want to either, and she also does not want me to hide it in the wall in case it has a disastrous problem.

If my freshwater tank smells bad, that's something I'll want to deal with sooner rather than later.

edit: it seems the recent conversation is about grey tank venting. I'll cross that bridge when I get there. I was only asking about the dip tube. Sorry about necroing the venting thread.

Yes, our freshwater tank has a vent that is next to the filler, so it's low. I think it just has to be above the tank + splashing.

Regards,

Mark

 

[blutow]

My freshwater tank will be in the van interior and I'm thinking I'll take the upper .5" NPT port and put a tee in it to a) an overflow drain through the floor and b) a vent that curves a little bit and comes out through a vented hole in the wall. I debated just doing the overflow but don't want a siphon effect either (although I don't know how the siphon would happen if I don't run a tube into the tank). The wife does NOT want me to go to the roof and I don't want to either, and she also does not want me to hide it in the wall in case it has a disastrous problem.

If my freshwater tank smells bad, that's something I'll want to deal with sooner rather than later.

edit: it seems the recent conversation is about grey tank venting. I'll cross that bridge when I get there. I was only asking about the dip tube. Sorry about necroing the venting thread.

Can't you combine your vent and overflow? As long as it enters near top of tank, there is no way to create a siphon. Just do an upside down "U" and then down through the floor.

When the van is in motion, water will shift back and forth with significant force and can surge out overflows and vents (think geyser effect). You want them exiting under the van (or through roof). No way I'd want a vent inside the van, but maybe that's not what you are saying.

 

[akadaedalus]

Can't you combine your vent and overflow? As long as it enters near top of tank, there is no way to create a siphon. Just do an upside down "U" and then down through the floor.

When the van is in motion, water will shift back and forth with significant force and can surge out overflows and vents (think geyser effect). You want them exiting under the van (or through roof). No way I'd want a vent inside the van, but maybe that's not what you are saying.

I can be convinced to forget the split vent/overflow part. I guess mainly if I do combine them then when filling the tank to overfull the air will have to come from the gravity fill inlet while it's open which is probably not a big deal and I see what you mean about the upside down loop. The inlet does need to be sealed when not filling because it's also inside.

Here's another one. In this video

(skip to 27:30, there's a lot of blah blah) the guy hooks up the hot water tank pressure relief valve to the overflow drain which seems like a good idea but I haven't seen that done anywhere else. I did see another video where they just opened the relief valve in an RV (bare handed) and let it splash over everything which seems ridiculous.

 

[Kajtek1]

Nobody checks the codes on camper conversion, but WH safety valve can spray boiling water and codes require it to be pointed to the ground, with limited raise.
Pex is rated to 180 or 200F temperature. Boiling water is above that.

 

[akadaedalus]

Hmm. But apparently sometimes it leaks and sometimes it needs to be intentionally vented. Maybe I'll run a length of copper before joining to the common PEX drain.

 

[blutow]

Nobody checks the codes on camper conversion, but WH safety valve can spray boiling water and codes require it to be pointed to the ground, with limited raise.
Pex is rated to 180 or 200F temperature. Boiling water is above that.

Yeah, I wouldn't use PEX under pressure above rated temp, but I did use it for the ~4" section between the safety valve out through the wheel well (my water heater sits right above the wheel well). I figure it's probably going to be fine with that short section and no pressure build up

 

[RVBarry]

I'm checking my plans against yours (as I did with my electrical) and I have a question. What is the "dip tube" for?

Hi, on my phone right now so it’s hard to see all the diagrams, but iirc the Dip Tube is to get the pickup lower in the freshwater tank than a simple tap.

I’ve acquired the NW Conversions 36gal Wheel Well Tank, a Class A Customs 15gal (iirc) undermount gray tank, and the Isotemp SPA 15.
But they’re not mounted or plumbed yet.

 

[akadaedalus]

Hi, on my phone right now so it’s hard to see all the diagrams, but iirc the Dip Tube is to get the pickup lower in the freshwater tank than a simple tap.

Great, I wondered if that was the case. Googling "dip tube" wasn't getting great answers. I probably won't do the same unless I get frustrated with losing the last gallon or so. Seems like it's just one more thing to get dirty or malfunction.

I’ve acquired the NW Conversions 36gal Wheel Well Tank, a Class A Customs 15gal (iirc) undermount gray tank, and the Isotemp SPA 15.
But they’re not mounted or plumbed yet.

Good luck. I went with a smaller NW tank because of layout compromises and we decided to go with an electric heater and decide if our use case demands the much more expensive Isotemp solution.

Sorry for necro-spamming your year-old thread. All I wanted to know was what the dip tube was for.

 

[Graphite Dave]

I have a 24 gallon custom 14 ga. SS tank over and in front of the passenger side rear wheel housing. Tank has interior baffles, 1/2" tubing vent located in center of the tank with a pneumatic air valve sintered exhaust muffler on the end located under the sink countertop. A 1" PVC fill pipe located at the slider door with a boat transom expandable rubber plug as a pipe plug. Fill tank through the open slider door using a 90 degree radiator fill valve.

Never directly connect tank to hose pressure. No issues with the design.

Water System | Orton Travel Transit (ortontransit.info)

 

[vincelif]

Hi, this is my current water system plan; I'm looking for feedback and I have a few questions to follow.

Notes:
Will use 1/2" PEX A for cold and hot water.

Will use a pump with bypass, so an accumulator/bladder tank shouldn't be needed.

Gravity fill and drain/sewer lines will be larger, probably 1.5 - 2" for the fill, and 1.25" for the drains.
There will be a water-tight cap on the fill inlet (needed as it won't be much higher than the tank due to the bed being there).

Hepvo docs say they don't need an air inlet as long as there is a vent downstream. Also, it's possible to have a single Hepvo for 2 drains if each is within 6' of the valve, so I'm considering using only one Hepvo.

I might put a heating pad on the freshwater tank, but it will be indoors (with an Espar) and I don't ever plan to leave the van unattended for long in subfreezing weather.
I can put RV antifreeze in the drains if needed to protect the gray plumbing.

The toilet will be a Port-a-Potti (cassette) and will not be connected to the plumbing system.

View attachment 224923

Going to be studying this drawing forever. Thank you do you have any pictures of your plumbing. Laugh out loud thanks

 

[RVBarry]

Going to be studying this drawing forever. Thank you do you have any pictures of your plumbing. Laugh out loud thanks

Hi, so far I've got both tanks and the water heater, but that's it... No pipes yet.