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Well Pressure Tank located upstairs?

Steve_Hoff's picture

Hi all...I'm new to the forum but was hoping to get some input from you guys!

 

I'm building a 2-story house, on a basement, with a finished attic (with bath)...so that means I could have a bathroom 4-stories up in a home served by a well.  

 

Has anyone ever put the associated eqiupment upstairs and then plumbed down from it?  Instead of losing pressure on your way up you could install a pressure reducing valve at each floor on the way down to keep it even throughout the house?

 

A quick glance through the 2012 IRC and I couldn't find any prohibitions, but that doesn't mean it isn't in there...  If it's legal also doesn't mean it's a good idea.

 

Thoughts appreciated!

-Steve

 

 

You generally want the pump (post #211909, reply #1 of 25)

You generally want the pump as low as possible, to minimize the length of the suction line.  (This isn't just a niceity -- there's an absolute limit to how deep a given pump can "reach".)  The pressure tank can be anywhere, and it used to be common to put (non-pressure) tanks in the attic.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

When you say the "suction (post #211909, reply #2 of 25)

When you say the "suction line" are you assuming a jet pump style well?  Mine (not drilled yet) is probably going to be deep enough to need a pump at the bottom, pushing the water.  So I should just be able to factor the extra height into the decision of what pump to buy?

...or do you have a concern about suction within the system...say if the water is on downstairs and for some reason water can't enter the system to replace it (...a failed pump or a closed valve somewhere...) ?

Yes, if you have an (post #211909, reply #3 of 25)

Yes, if you have an in-the-well pump, the pump is about as low as it can go.  But often a deeper-than-33-feet well is handled using a "jet pump" -- a scheme where water pressure through a second pipe powers a sort of siphon at the bottom of the well.  This technique has its limits, and it's not a good idea to unnecessarily add distance (especially height)f between the "real" pump and the siphon.

(And, obviously, a "shallow well pump", since it depends on atmospheric pressure to lift the water out of the well to the pump, cannot be higher than 33 feet (atmospheric pressure) above the bottom of the well, and the practical limit is something closer to 20 feet.)

You always have the possibility of developing suction in a water system.  (This is why hose spigots are supposed to have vacuum breakers.)  A standard water system can handle this, within reasonable limits.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

The average well around (post #211909, reply #4 of 25)

The average well around Buncombe County, NC is about 450'.  With the shallowest being around 200' and the deepest 800', so I think I'm in for the other-other kind of pump...

Assuming I can put in a well to get the water upstairs, I can't find anything online about folks "starting upstairs and plumbing down".  I figure I'll need a pressure reducing valve on each floor.  I'll I need to it make accessible so it can't be adjusted and replaced. 

If I didn't step down the pressure, the basement would have all the water pressure of the system itself and the water column above it and I'd still end up with pressure problems with water running on two different floors?

The pressure difference from (post #211909, reply #5 of 25)

The pressure difference from floor to floor would be on the order of 5 psi.  "Typical" water pressure is between about 25 and 75 psi.  There's no real need for pressure reducers until you get above 3-4 floors.  The main "trick" in your scenario is that pressure varies about 10 psi from pump start to pump stop, so if you want the minimum pressure on the 3rd floor to be 25 the the maximum pressure on the first floor will be about 65 psi.

Do note that where the pressure tank is located has no effect on any of this.  Water is an "incompressible fluid" and observes Pascal's law.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

Pressure tanks contain a lot (post #211909, reply #6 of 25)

Pressure tanks contain a lot of air and are compressible, otherwise there would be no need for them.  The purpose is to avoid short cycling the water pump.  But really, there will be a slight difference in pressure between floors, but as long as the pressure is high enough, no one will notice the difference.

The pressure reducers, (post #211909, reply #7 of 25)

The pressure reducers, though, should help "hold the water back" so that if the toilet is flushed in the basement there won't be as dramatic of a reduction to the flow in the shower in the attic? 

The weight of the water column "sitting on the well pump" instead of the water "falling from the top" (and creating low pressure behind it as it falls to help to pull water up from the well), would work against the system, with the friction of the lines also making it worse?  I'd have almost nothing left at the "fourth floor"? 

My two story house now, on a tall crawlspace, with the well pump cranked up has a noticeable difference between floors.

Seems like it's setting up your own little water tower?  Top-down plumbing like this would probably save on electricity and wear on the pump too?  The water falling, through suction, tries to pull water up from the well to repace it?

So, I guess there's two questions....will pressure reducers on the way down reduce the "flush effect" upstairs?  Will the system generate suction and help (equal  to the weight of the water used, less friction and turbulence) pull water from the well to replace it?

Pressure reducers would help (post #211909, reply #9 of 25)

Pressure reducers would help to equalize pressure between floors.  But the location of the tank will have zero effect, other than affecting the length of pipe (and hence flow resistance) from tank to fixture.

However, if you were really obsessing on this you could place a small pressure tank on each floor, downstream of your pressure reducer, in addition to the centralized one.

But note that modern (less than roughly 20 years old) toilets (even the cheap ones) tend to be much better about "starving" a shower, etc, than the older ones.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

system design (post #211909, reply #8 of 25)

Steve,

          There are several considerations when designing a water supply system - define the peak demand flow requirement, determine the well depth, recovery rate, capacity, static water level, and, are there any water chemistry / condition issues?

           You may want to consider using a constant pressure water pump; ECM technology allows these pumps to provide constant velocity to match the flow rate, ramping up or down as needed. ECM pumps can conserve electricity, and, they operate without a large storage tank..........

 

 

System design/flow rate for a well... (post #211909, reply #11 of 25)

So,  a well can only sustain what it can sustain and it seems like it's almost never as much as you'd like.  Any tips to make the water seem more abundant?  I'd hate to design a system that's always drying the well...or one that's uncomfortable in the house.

I figure the low-flow fixtures are a good idea.  A regular tanked water heater, maybe increase the diameter of some of the pipes...make my kids take sponge baths...

 

 

Good points! (post #211909, reply #10 of 25)

Good points about the pressure tank and how it works with cycling the pump.  I think I could have titled my post a little better, but I couldn't figure out how to explain my "top down" plumbing plan other than describing the in-the-house well eqiupment being in the attic.

Seems like the concensus is one pressure tank for the house, if required by the type of pump going in the bottom of the well.  I'll absolutely look at the different kinds of pumps and make a good decision for the house with the well guys.

I also haven't heard of any code issues or "real" issues with plumbing that way.  The idea seems like it would solve the low-pressure-upstairs problem that houses on a well always seem to have?  Do you guys agree?  If it does help with that problem, why isn't it more common?

Which "that way" are you (post #211909, reply #12 of 25)

Which "that way" are you talking about, that isn't more common?


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

1psi = 2.31 feet of elevation.......... (post #211909, reply #13 of 25)

'' Top down '' plumbing is very rare, and not needed in most residential applications. Standard pressure switch / storage tank water systems can be set to deliver water between 50 & 70 psi; in this case, there would only be a 10 psi difference between a bathroom on the first floor & an attic bathroom. A constant pressure pump, set at 75psi continuous pressure at the basement entry point, would deliver aproximately 62.5 psi to an attic bathroom.............

Pressure loss vs elevation (post #211909, reply #14 of 25)

What's the point of the different sized water storage/pressure tanks?  What's the application for the big ones?  Would they help run "two showers" at a time (or laundry, or dishes, or...)

Thanks a lot for your help guys!  I'm at the right point in the design process to make accomodations in structure for the house's systems and I'm building the place for myself; I'd rather splurge on plumbing that countertops, if you know what I mean.  I don't mind going a little fancy/robust here.

The "size" of the tank (post #211909, reply #15 of 25)

The "size" of the tank determines how much water you can draw before the pressure drops below the low-limit and the pump kicks in.  A larger tank (within reason) is a bit more efficient and easier on the pump.  Plus it's annoying for the pump to be constantly switching on and off every 15 seconds.

(Do note that "size" is specified several ways, and sometimes a "captive air" tank with a bladder is specified as having a gallon "size" that a larger bladderless tank would have to have to produce the same results.  It's been decades, but I'm thinking a "100 gallon" bladder-type tank would have an actual capacity of about 60 gallons, unless they've changed the terminology.)


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

Thanks, Dan (post #211909, reply #16 of 25)

Thanks for the tips, Dan! 

I think I'll give the "top down" system a shot because it'll allow me to make adjustments that I won't be able to make otherwise.  Like Patton said, "A good plan executed now and violently is better than a perfect plan next week." 

So, in the spirit of overkill...I'll design in an appropriately sized water heater and storage tank for each floor. 

I'll step the pressure down (lowest pressure on the lowest floor) through pressure reducing valves so as I go downhill the lower storage tanks cycle when water on that floor is used and won't try to push water back up the pipes. That should allow, for a short time, anyway, more water to flow out of the system than comes up from the well. 

With all that equipment to maintain, I'll place valves in smart places to isolate components and make servicing easier.

Filters will only be upstairs...I'll probably have to go after sediment and Manganese here, that stuff is smelly.

Once I see the flow I'll be able to get from the well I'll choose fixtures that in likely combinations won't exceed the well/well pump's capacity.

Probably overkill, but do you see any problems I'm not thinking of?

...about the storage tanks... (post #211909, reply #17 of 25)

...after my coffee this morning...

I think the plan will only work with one storage tank, located upstairs where the pressure in the system is the highest.

If the tank on the upper floor is at the highest pressure, it will always be the one to "squeeze" water downhill and into the lower floors.  If I let the pressure rise at the lower floors, instead, the storage tanks there could try to push their water back uphill.  Keeping all those pressures and valves balanaced out would be too much work...so, just one water storage tank.

I think you are going (post #211909, reply #18 of 25)

I think you are going overkill, but...  Anyways, here's a link to a converter from water column in inches to PSI. The PSI difference in 10 feet of water is 4.3 PSI.  You can play with it make calculations.

http://www.convertunits.com/from/water+c...

You're still hung up on (post #211909, reply #19 of 25)

You're still hung up on "uphill" and "downhill".  That's a meaningless concept in a watertight, pressurized pipe.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

That's correct.  In order to (post #211909, reply #20 of 25)

That's correct.  In order to get the pressure the same at each floor the bottom three floors are going to need regulators.  The position of the tank will make no difference. 

Also the difference in 480 inches (40 feet) of water is 17.3 PSI which might be noticed, but might not.

Another note, a recirculating hot water loop could eliminate any advantage of multiple water heaters other than having hot water on other floors without failed heaters. 

Using multiple heaters will result in higher energy use, and costs due to the lower efficiency and purchase costs of multiple heaters, and the replacement costs will be higher too.

Finally, who wants to carry a water tank or water heater from the attic to ground level?  They will eventually fail.

Thanks, guys! (post #211909, reply #21 of 25)

Thanks for all the help guys.  It helped me to organize my thoughts. 

I had a good talk with the old plumber that was working on a remodel at our business the other day and he added some thoughts too. His quotes were, "Shoot, yeah, it always works better if you start at the top" and "I don't know if you need those valves and stuff, but I guess it'll help manage the thing."

He also talked me into PEX for the project.  I guess there's something in the wells locally that slowly eats through copper pipe in about 20 to 30 years, even the good pipe (not the rolls). 

As for the hot water circulator, I think we get right back into all the pressure issues again and might have hot at one pressure and cold at another (if I'm using the pressure reducers)...balancing valves in some fixtures, etc.  I'll probably just have a little PEX manifold on each floor and keep it simple.  Plus, some floors use hardly any hot water...one floor only when we have guests...we'll probably use a mix of heater styles to keep the cost down.

For the access...we need stairs to access a water heater where I'm at.  It's a finished attic in this house, replacing it won't be a problem.  My wife and I did carry an old 80gal out of the attic in my old New Orleans house, though.  That was dangerous.

I'm on to the HVAC plan!

Great minds ... (post #211909, reply #22 of 25)

Steve, I'm actually working on a nearly identical system. My well tank is on the floor in the basement and my second floor showers are 27 feet above that, which gives me an effective loss of about 12psi. I'm currently running my pressure switch at 40/60, so my showers go from okay to dismal.

If you'd like we could exchange some notes and vendor information. My account is too new to send a PM to you; you could either try sending me one or shoot me an email at: oomgoshcd at gmail dot com (you know with the "at" and "dot" replaced with the apprioriate symbols).

Sadly I don't get to build from scratch, but I have installed a lot of water treatment in the middle of the system in my basement. One stage of the treamtent requires me to go to atmospheric pressure and then have another submerisble well pump which brings me back to the 40/60 range. My current plan is to place a pressure thank with the pressure switch on my second floor without pressure reducing valves down line. It'll give me only a 4psi loss at my shower heads and keep my lowest basement devices (toilet) just below 70 psi max ... although it is tempting to place reducing valves all around.

One note if we don't get in touch. Depedning on the amount of room you have upstairs and how much stored water you're comfortable with, you might conside placing a small pressure tank with the swtich in the attic and a larger pressure tank somewhere else like the basement (I'm in the middle of sourcing some drain pans and elctronic water cutoff valves). The tank in the basement will be operating at a higher PSI and will have a lower draw down (drawn downs decrease as the system pressure increases).

 

As an aside in response to some of the comments DanH makes, watertight incompressible system aside: There is still gravity which cause water column weight and hence change in pressure depending on which floor you're on. This is why tall buildings have water tanks and pressurization systems on upper floors. Also if anyone is confused or not sure who to trust, you can buy an inexspensive pressure gauge and attach it to a line in your basement and to a line on your top most line (like the shower head outlet) and you'll see the pressure loss due to the weight of the water column.

My thoughts on your thoughts (post #211909, reply #23 of 25)

I didn't get a chance to build yet, but I've talked to a few more plumbers and had my well drilled.  The quote I got from one old guy was, "yeah, it always works better if you plumb from the top"...

I'm currently working through the different well pump options to get that decision right.  The variable I didn't know before was how deep my well was going to be and how much water I'd get from it.

The good news is that I'm lucky.  I hit over 50 gpm (not kidding, they couldn't really measure it) from within granite at 360'.  So, having some water storage via large pressure tanks in the building won't be necessary.  Also, the shallow-ish depth of the well won't add any additional pump problems.  However, it's a littly smelly, so I probably have to contend with the issue of pushing that water through some filters (which will definitely mess with the flow as well).

As for the pressure upstairs, the previous comment about pressure being even across the house was correct...for static pressure.  I think your comment is correct as well.  The instant your open a valve you're working against dynamic pressure which is subject to all kinds of varibables including the height of the water column and the "friction" inside of your pipes to include contact with the walls and turbulence within the lines.  Some really nerdy dudes have equations that work for long straight lines, but nothing can calculate what's actually happening in your house.

Lots of words, but, did you confirm you have a pressure issue instead of a flow issue?  If you screw off the shower head and plug on a pressure gauge then take readings with nothing turned on and then another with, say, a toilet being flushed downstairs you'll be able to get some good insight?  If the pressure falls to nothing, then that's the problem.  If it stays reasonable, then maybe you aren't getting good flow through your supply lines and need to increase the size, remove some bends, etc?  

If your well pump is strong enough, and nothing else is turned on in the house, and there are no other supply-plumbing problrems, you should still have a strong shower upstairs. 

My house now is terrible upstairs, but it's definitely an issue with the supply lines.

Just my $0.02.

Height differences affect (post #211909, reply #24 of 25)

Height differences affect only the static pressure differential.  Dynamic pressure differential is determined by flow rate "multiplied" by the "restrictiveness" of the pipe.  (Not really multiplied, but a "non-linear" relationship.)  Add together the static pressure differential and the dynamic pressure differential and the well head pressure and you get the pressure at a given fixture.

Differences between hot and cold pressure would only occur due to uneven dynamic pressure conditions -- height would have no effect.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

Tall buildings divide the (post #211909, reply #25 of 25)

Tall buildings divide the plumbing into zones, each covering maybe 3 floors, and each effectively a different system, with it's own pressure regulator and maybe a tank, to handle "surge" capacity.  One or more pumps boost the pressure to that needed for the higher floors.  This is really no different from having multiple well systems.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville