Maximum PSI at home with water booster pump receiving 50 PSI from utility water main?

KStrick

Hi! Our new washing machine is showing an error code for low water pressure. The Miele tech says this can impact performance and we should address it.

The water company came out and confirmed they are delivering 50 PSI at the street and that we are getting 40 PSI in the home (water must travel roughly 20 feet uphill from water company main below). The water company has recommended we purchase a water booster pump to increase the PSI in the home as they cannot/will not be able to increase pressure. If the water company is delivering 50 PSI max and with the uphill flow, will a water booster pump provide much additional pressure in the home?

We recently replaced all plumbing under the home; no leaks.

Would appreciate any thoughts from experts.

pecmsg

Rather then guess install a gauge that will measure so you’ll know. 

KStrick

Appreciate the comment. We already know the pressure at the water main/supply. The water company used a gauge to measure it at the fire hydrant near our house. It is $1,200 for a water booster pump plus the cost of labor for a plumber. If the pump cannot increase pressure beyond water company 50 PSI, there is no reason to pay this expense. We would have to live with it and file insurance claims against the water company should the machines fail.

Maybe my question should be, how high can we increase our water pressure at the house with a booster pump receiving only 50 PSI from the utility water main? I don't know how the booster pumps work. Can they boost from 0 PSI?

pecmsg

What the pressure in the House?

standing and running?

How much higher do you need it?

Intplm.

I have been setting water pressures at 65psi. Including in my own home.
Thats how high you can have the main pressure without causing other possible issues.

Would that number satisfy the Miele Tech?

EBEBRATT-Ed

40 psi should be fine for a washing machine.

Make sure it isn't a problem with the washer before you go the expensive route of a booster pump.

Check the manual for the washer or other literature and see what pressure it needs. I would be very surprised if it won't work at 40.

Jamie Hall

Depending on the booster pump and the size of your water line to the house (which sounds undersized if you are seeing a 10 psi drop for only 10 feet of elevation, by the way) you can go as high as you want. Just depends on the pump. That said, anything over 80 psi static pressure in the house will very likely cause major problems with fixtures and any flex hoses (like washing machines). Now there is, however, a limit to flow -- not pressure -- and that depends on how much pressure drop there is through your outside water line. You should not drop the pressure at the house connection to less than 20 psi at maximum flow.

Intplm.

Would it be more economical to replace the appliance with one that works with your homes water pressure?
The current pressure you have should be just fine with any appliance.
Im wondering if this is specific to your appliance and only your type of appliance.

hot_rod

Check the screens on the washer hoses. Plugged screens will cause a pressure drop as it tries to fill
30 even 20 psi should be adequate

pedmec

Make sure your isolation valves to the washing machine are fully open and feeding water to the machine. 40 psi should be fine. where was the water pressure measured in the house.

yellowdog

@KStrick You would file suit against the water company because you bought a washing machine that was not compatible with the existing conditions in the home? Nice guy you are.

Mustangman

I assume your booster pump is a constant pressure pump? If you have 40 psi standing pressure, that pump will easily get you to 60psi. I don't go any higher with pressure in a house. Toilets will start running, faucets can open. I personally have 30 lb coming into my house. I called the water company and they tell me 30 psi meets their minimum delivery pressure. I beg to differ on that one. My water line comes off a dead ended main. A taco constant pressure pump is in my future. Grundfos makes a nice one too. Both are really quiet. Years ago we would mount a jet pump on like a 205 well tank and hook up your main to the suction side of the pump. Discharge gets piped just like a well pump tank. The only problem is noise. Jet pumps are a bit loud. Good luch

Jamie Hall

Couple of unhappily necessary comments here. First, most -- if not all -- appliances are built to work satisfactorily on anything from 30 to 80 psi. If the OP's washer doesn't, something is wrong with the washer or its immediate installation.

Second, there are very exacting codes on the State and sometimes Town level as the minimum acceptable pressure in a municipal water system. Interestingly, they are the same pressure range: 30 to 80 psi. And that is static water pressure. No, or very low draw. Having designed and run a few of these systems, I can assure everyone that that is checked surprisingly frequently. I can further assure you that in communities with substantial elevation differences one sometimes needs to get rather creative!

CLamb

I looked up the specs for one of the Miele washing machines (chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://media.miele.com/downloads/82/ff/02_C7F12828B6261EDE98D1BC7CB1C582FF.pdf). It shows a minimum flow pressure of 14.5psi.

Zman

My guess is that you either have an issue at the washer like a clogged screen or bad sensor or your house pressure drops under full load with lots of faucets open. Go buy a $12 gauge that will thread onto a hose fitting and monitor the house pressure under different conditions. 40 PSI should be plenty for the washer. https://www.amazon.com/Stainless-Single-Pressure-Internals-Display/dp/B09389XJ55/ref=pd_lpo_sccl_3/143-7307539-9505220?pd_rd_w=B1Ws7&content-id=amzn1.sym.eb6ee5e1-c2c2-48f8-a92b-80fda933018c&pf_rd_p=eb6ee5e1-c2c2-48f8-a92b-80fda933018c&pf_rd_r=DKMVFR25CZXH40EX7T3D&pd_rd_wg=rN1YI&pd_rd_r=bf96581c-7cc5-4d8f-bf2d-7e8ba93375de&pd_rd_i=B09389XJ55&psc=1

hot_rod

I think plumbing codes suggest no less that 20 psi, no greater than 80 psi

If a valve like the main or meter yoke is only partially opened you will experience pressure drop as faucets open.

Is there a pressure reducing valve at the incoming line? Those also have strainers.

PRR

CLamb said:

I looked up the specs for one of the Miele washing machines.... It shows a minimum flow pressure of 14.5psi.

Yes.

I have a well and a modest pump. My pressure dips below 20PSI, and that is very lame. The generic washer washes just fine. Just takes longer to fill.
As Zman is saying: you can have fine pressure at the street, at the meter, at the garden hose, or kitchen sink... and still have a clog in the line to the washer outlet or in the washer hoses. Pressure WILL vary with flow-- high when little or no water is flowing, dropping low when washer or bath is running full. The $12 hose-fitting gauge he points to will show the actual pressure AT the washer connection while you try different conditions. A clogged screen is possible especially if you have been working on pipes. (An amazing amount of crud came out of my old pipes.)

KarlW

Former municipal water engineer here. As others said, the minimum pressure varies per state/jurisdiction.

New York uses “10-State Standards,” This is a minimum of 35psi although 20psi is allowed by exception (less than that and there is risk of bacteria getting through the pipe crack. The maximum is 100psi. In Rochester, NY houses along Lake Ontario (250 feet lower than downtown and 750 feet lower than the source at Hemlock Lake) have pressure reducing valves as its 120psi at the main.

I think you said you checked the pressure in your house? The only way it would be the water service is if the pipe connecting your house to the main has a major leak, but you would’ve noticed this at faucets and shows.

As everyone says, your machine is the likely the culprit.

hot_rod

80 psi is max. under UPC/ IPC 100 psi can be tough on toilet ballcocks

KarlW

hot_rod said:

80 psi is max. under UPC/ IPC 100 psi can be tough on toilet ballcocks

Aren’t competing codes with jurisdiction fun?

hot_rod

KarlW said:

hot_rod said:

80 psi is max. under UPC/ IPC
100 psi can be tough on toilet ballcocks

Aren’t competing codes with jurisdiction fun?

I think we are down to two major codes now UPC and IPC. UPS claims to be the more strident code.

The old southern states BOCA National plumbing Code seems to be gone?

Wisconsin still has it's own SPS plumbing code.

KarlW

But the plumbing code is different that water purveyor code. It matters for the (relatively few) areas that operate between 80 and 100psi.

Because of competing code, the purveyor will reduce pressure to 100psi, but the homeowner is responsible for reducing to 80psi.

There are undoubtedly homes out there with two pressure reducers one in the street to 100psi and one in the house to 80psi, where only one pressure reducer would suffice.

Intplm.

If all issues with the appliance are resolved, and the water pressure issue is truly resolved, then adding a way to boost your pressure... then go for it.

@KStrick

What ever you decide be sure to have a way to adjust the pressure to your needed specs.

hot_rod

KarlW said:

But the plumbing code is different that water purveyor code. It matters for the (relatively few) areas that operate between 80 and 100psi.

Because of competing code, the purveyor will reduce pressure to 100psi, but the homeowner is responsible for reducing to 80psi.

There are undoubtedly homes out there with two pressure reducers one in the street to 100psi and one in the house to 80psi, where only one pressure reducer would suffice.

What code do water purveyors follow? Seems the AHJ would make the call for pressure within the building?

A 3-1 pressure reduction is workable with residential pressure reducers. So a 240 psi service could reduce to 80 in one step if the PRV is rated for that pressure

Assuming the service lateral is rated for that pressure

Jamie Hall

The water supply people are going to try to keep the static pressure in their lines to something reasonable -- and 100 psi is reasonable. They are not going to raise it above that, as things will break or even if they don't break, leak. They also try to keep the minimum pressure under certain specified conditions (fire flows -- there are codes and manuals) above atmospheric (they don't always succeed -- which is why the plumbing codes mandate reduced pressure zone backflow preventers or air gaps on some equipment). Again, in case of leaks, as they don't want to run the risk of drawing contaminated groundwater into the mains, although that does happen.

Designing a small public water supply system on relatively level ground is pretty easy. Designing one in hilly terrain, or a larger system with a number of potential loops, can get very interesting -- and really lots of fun in its own slightly perverse way. Modern computers make it pretty easy, though. You really try very hard to use gravity flow as much as possible (usually you can) for distribution, though you may have to use pumps to get the water up to your storage. It is somewhat surprising, though, that many big systems are all gravity flow except for a few isolated districts.

PRR

Jamie Hall said:

...Designing a small public water supply system on relatively level ground is pretty easy. Designing one in hilly terrain, or a larger system with a number of potential loops, can get very interesting .... try very hard to use gravity flow as much as possible (usually you can) for distribution, though you may have to use pumps to get the water up to your storage. It is somewhat surprising, though, that many big systems are all gravity flow except for a few isolated districts.

Water Supply and Sewerage, Steel, E. W. with others, every few years through the later 20th century. The 1953 edition:


City water design is a lot about fire requirements. A bad warehouse fire may take more water in one night (always at night) than in the 50 years before. The city next to my town is all about the 1920 fire, the mains, the dams, the lakes.


In the diagram, water enters at "A" and flows all over town, with exits uptown and downtown. The tables show a recursive design: assumes different major buildings are burning, figure the water demand, guess pipe size(s), figure the pressure drop for all possible paths, they won't agree so fudge a bit and figure it all again, until agree within 50GPM.

Jamie Hall said:

...fun in its own slightly perverse way. Modern computers make it pretty easy

But (as you know), most city water was laid out before electronic computers. You had slide-rules (and maybe adding machines), and you had human computers (a job description).

Strongly endorse this book, and there are so many surviving copies that casual readers can afford one. Loverly drawings of waterworks and also the massive sewers such as Texas wetlands.

Jamie Hall

Yep, That exact book is sitting on my shelf about 10 feet away as I type this... and my old Pickett slide rule is in my desk still... (still works. No batteries required...)

pecmsg

Jamie Hall said:

Yep, That exact book is sitting on my shelf about 10 feet away as I type this... and my old Pickett slide rule is in my desk still... (still works. No batteries required...)

or C wire

PRR

Jamie Hall said:

...my old Pickett slide rule is in my desk still... (still works. No batteries required...)

My Dietzgen Micromatic was borked before I got it. Looks like a kid pried the (ivory?) faces off, and one (CF CIF L CI I) was re-glued upside-down. The gluing is neat and it took a while to see what was wrong. My daily (maybe thrice a year) driver is a pearwood AcuDesign (I believe a rebrand Charvoz-Roos)(not shown). But TI has spoiled me ever since LEDs only came in small/red. Batteries last a decade. I pick up spare TI-30s at yardsales so if a battery or button fails, or I just do not like the display (they varied), I can mix/match and be content.

Jamie Hall

Replaced mine with an HP38. Loved it... wonder where it is?

PRR

Jamie Hall said:

Replaced mine with an HP38.

What, in 1980?

Jamie Hall

Maybe it was a 33... I forget. But yes, around 1980

PRR

H-P was pushing 6 models. The 38 is financial, mortgages investments and monthly payments. The 33 is scientific, so your TAN LOG SIN etc stuff. 37 is business calculator- I do not know what that does (that's not in financial or scientific). TI seems to dominate this field but H-P has a page about business calcs:
https://www.hp.com/us-en/shop/tech-takes/top-3-uses-business-calculator

Jamie Hall

So mine was a 33. I don't do financial! I still wonder where it is... must be around here somewhere. I liked it!