Critique my plumbing plan

[Kentucky Dreaming]

OK. I understand that every skoolie is an individual beast of steel!!

[Tejon7]

Ok, second draft. I've omitted the finer details on this next set of drawings and just focused on the tank area.

Valves drawn parallel to the pipe are open and those perpendicular to the pipe are closed. The thick blue and red lines indicate the path of water in each scenario.

This first one is "Boondocking mode" or all water being pulled from the water tank:


Here's "City water mode":


Here's "Tank Fill / Drain mode" where a pressurized hose fills the tank, or the same pathway is used to drain the tank:


And finally, "Tank suction fill mode" ("Suck Mode" for short):

Edit: added a ball valve at main tank outlet, mainly for Suck Mode.
Edit 2: Got all the pictures wrong. I think they're correct now

Do you all see any problems that I'm overlooking? Or are there any ways to make this simpler but still maintain the functionality?

One other thought - does anybody know if water will flow the "right" way through an un-powered diaphragm pump? In other words, if the pump is off, could city water still flow through it in the "normal" direction? If so, I could achieve this same thing with a lot fewer valves.

[rffffffff]

Other than the vent missing which I assume is just a drawing problem I think it looks okay… that all said it can be much simpler. I’ll draw mine here real quickly if I can and post it, otherwise I’ll try to get it done tomorrow.

[rffffffff]

https://imgur.com/gallery/2xDiEGK

So I usually leave city valve closed and vent open.

V1 stays open almost all of the time.

V3 closed allows me to run on city water pressure (which flows through the pump no problem, but I also can leave the pump on for better pressure) but if I hook up to city water I leave v3 open until city water starts flowing out of my vent and the (tank is full), then I close v3.

Closing v1, v2 open and v3 closed is suction mode. I made it so ‘normal operation’ is all valves vertical and suction mode is all valves horizontal so it’s easy to remember.

Only thing that’s missing here is a check valve between cold water manifold and hot water heater because it was back flowing. I also have an inside valve for the city water line but I don’t ever use it.

For you hot water recirc would just tee into the vent system with appropriate check valve so it doesn’t run out the vent.

I would add a sediment filter before the pump and probably a really cool US water quantum filter (kills bacteria and viruses and has a carbon finishing filter, really cool) after v1 on the next go round.

Hope that helps!

[ol trunt]

Neither of my major brand pumps will pass water in either direction when not in use. Due only to space constraints my pumps must run to flow regardless of water source. It would be easy enough to plumb your city water into the system after the pumps to avoid this issue.
Jack

[Danjo]

I’m sorry if I missed it, why two pumps?

[Rucker]

I'm with you on the recirculation, but I don't actually know how my instant water heater will behave. The unit is installed, but I'm doing some test setups to see how well it works with no modifications, then with a recirculating pump. The recirculating pump will tee right at the cold water inlet to the water heater, and I'm debating on adding some capacity right there, like an accumulator or some tiny tank to increase the volume of heated water available at the shower. I'm guessing if I need to put the recirculator in I'll put it on a mechanical timer switch, which I'll set a few minutes before using the shower.

These instant heaters trigger on temperature and on flow, but I don't understand exactly how that works. I'm hoping the recirc pump will ensure the GPM minimum is met, and the extra volume of water will help ensure the water heater isn't fluttering on and off...if it is needed to prevent that first cold shock.

I also have a thermostatically controlled mixer valve, and I may use that instead of the cool vintage brass mixer valve I picked up last summer.

I'm a few weeks away from testing still.

[Tejon7]

Originally Posted by rffffffff

https://imgur.com/gallery/2xDiEGK

So I usually leave city valve closed and vent open.

V1 stays open almost all of the time.

V3 closed allows me to run on city water pressure (which flows through the pump no problem, but I also can leave the pump on for better pressure) but if I hook up to city water I leave v3 open until city water starts flowing out of my vent and the (tank is full), then I close v3.

Closing v1, v2 open and v3 closed is suction mode. I made it so ‘normal operation’ is all valves vertical and suction mode is all valves horizontal so it’s easy to remember.

Only thing that’s missing here is a check valve between cold water manifold and hot water heater because it was back flowing. I also have an inside valve for the city water line but I don’t ever use it.

For you hot water recirc would just tee into the vent system with appropriate check valve so it doesn’t run out the vent.

I would add a sediment filter before the pump and probably a really cool US water quantum filter (kills bacteria and viruses and has a carbon finishing filter, really cool) after v1 on the next go round.

Hope that helps!

That helps a lot, thanks! Yes, your plan is much more simple and straightforward. Time for another draft to pare down some of the PEX spaghetti in my last batch of drawings.

Interesting that your Shurflo passes water when powered off but Jack's pumps do not. I guess I'll go with the Shurflo then.

[Tejon7]

Originally Posted by ol trunt

Neither of my major brand pumps will pass water in either direction when not in use. Due only to space constraints my pumps must run to flow regardless of water source. It would be easy enough to plumb your city water into the system after the pumps to avoid this issue.
Jack

Now that I know that plumbing the pumps in line with city water is something people have done before, I think I'll just do that for simplicity's sake. I'd rather have fewer connections and potentially make the pumps work a bit harder.

Thanks for answering - I actually just found an older thread where you said your pumps don't pass water when off. Sorry to make you repeat yourself!

[Tejon7]

Originally Posted by Danjo

I’m sorry if I missed it, why two pumps?

Mostly just copying Jack

I really like the hot water recirculation idea to keep from getting a shot of cold, and he has a two-pump system that has been field tested. Correct me if I'm wrong Jack, but the purpose of two pumps is to assure that there's enough pressure to run the recirculation system at the same time as... everything else. Worst case scenario kinda thing - all taps on and still enough pressure.

Also, I like the idea of redundancy. If I had a single pump system, I'd still have a spare pump ready to go. This way, if one goes out my spare is already installed.

[Tejon7]

Originally Posted by Rucker

I'm with you on the recirculation, but I don't actually know how my instant water heater will behave. The unit is installed, but I'm doing some test setups to see how well it works with no modifications, then with a recirculating pump. The recirculating pump will tee right at the cold water inlet to the water heater, and I'm debating on adding some capacity right there, like an accumulator or some tiny tank to increase the volume of heated water available at the shower. I'm guessing if I need to put the recirculator in I'll put it on a mechanical timer switch, which I'll set a few minutes before using the shower.

These instant heaters trigger on temperature and on flow, but I don't understand exactly how that works. I'm hoping the recirc pump will ensure the GPM minimum is met, and the extra volume of water will help ensure the water heater isn't fluttering on and off...if it is needed to prevent that first cold shock.

I also have a thermostatically controlled mixer valve, and I may use that instead of the cool vintage brass mixer valve I picked up last summer.

I'm a few weeks away from testing still.

I'm a few months to a year away, so hopefully I can learn from your experience!

[Rucker]

Originally Posted by Tejon7

Interesting that your Shurflo passes water when powered off but Jack's pumps do not. I guess I'll go with the Shurflo then.

I missed that-are we certain Shurflo pumps allow water through when off? I've got to believe the pump check valve pretty much prevents any other pump from pushing water through the Shurflo when off.

[Danjo]

Originally Posted by Tejon7

Mostly just copying Jack

I really like the hot water recirculation idea to keep from getting a shot of cold, and he has a two-pump system that has been field tested. Correct me if I'm wrong Jack, but the purpose of two pumps is to assure that there's enough pressure to run the recirculation system at the same time as... everything else. Worst case scenario kinda thing - all taps on and still enough pressure.

Also, I like the idea of redundancy. If I had a single pump system, I'd still have a spare pump ready to go. This way, if one goes out my spare is already installed.

Oh, OK. I like the recirculating for the water savings when boondocking. Makes sense.

[Tejon7]

Originally Posted by Rucker

I missed that-are we certain Shurflo pumps allow water through when off? I've got to believe the pump check valve pretty much prevents any other pump from pushing water through the Shurflo when off.

See below:

Originally Posted by rffffffff

V3 closed allows me to run on city water pressure (which flows through the pump no problem, but I also can leave the pump on for better pressure) but if I hook up to city water I leave v3 open until city water starts flowing out of my vent and the (tank is full), then I close v3.

And on the previous page he said Shurflo 4008. I hope I was reading this right and not spreading false info.

[Danjo]

I don’t think the shurflo 2.0 allows water to pass when off otherwise how would it hold pressure when primed?

[rffffffff]

Originally Posted by Rucker

I missed that-are we certain Shurflo pumps allow water through when off? I've got to believe the pump check valve pretty much prevents any other pump from pushing water through the Shurflo when off.

I pass water through my shurflo all the time, but it’s coming through a relatively small diameter 75’ hose when I’m hooked to my well house and coming off of a 60psi pump in the well house, so the pressure is reduced. Usually I leave the pump on for increased pressure but I like it off in the morning so I can use water without the pump waking anyone up. You can see my diagram above in the Imgur link to see what it looks like.

[rffffffff]

Originally Posted by Danjo

I don’t think the shurflo 2.0 allows water to pass when off otherwise how would it hold pressure when primed?

Check valve maybe? Not sure but my 4008 definitely works that way, I use it like that often.

[Tejon7]

I think better if I have stuff to tinker with, so I've ordered a 4008, an adjustable pressure regulator, and fittings to hook it up to my garden hose. I'm curious to see if there's a certain pressure threshold at which the Shurflo will pass city water while off. Probably won't get around to this test for a while, but when I'd do, I'll post results.

[rffffffff]

Originally Posted by Tejon7

I think better if I have stuff to tinker with, so I've ordered a 4008, an adjustable pressure regulator, and fittings to hook it up to my garden hose. I'm curious to see if there's a certain pressure threshold at which the Shurflo will pass city water while off. Probably won't get around to this test for a while, but when I'd do, I'll post results.

My hose pressure after 75 feet is pretty low I think, it’s more of a low flow situation at low pressure. I don’t think you’ll find a hard cutoff unless it’s really low but I’m curious to hear.

[Tejon7]

In that case I'll try to get a ballpark flow rate for different pressures. At this point I'm also just curious.