Moen Flo and water pressure

[uscpsycho]

I bought a Moen Flo and then realized that it has a 3/4" connection but the main water line to my house is 1" so a reducer would have to be used. If you aren't familiar with the Flo this is it.

On their website Moen tries real hard to convince people that reducing to 3/4" will have minimal impact on water pressure. This is what I was told by support via email: At 60PSI you can get a maximum of 32.6 gallons per minute across the device. The pressure loss at, for example, 10 gallons per minute, is 1.7PSI.

I have no idea what this means for me. Would stepping down to 3/4" noticeably affect my water pressure? I have a tub filler that uses 7gpm and that's the highest capacity fixture in the house. Will I see a difference there or anywhere else?

In a few months Moen is coming out with a model that is 1 1/4" but it will be more expensive than the current model which is already quite pricey so if I had to get the larger one I might just pass on it.

Thanks in advance for any help!

 

[Terry]

Most three bath homes need 1"
Are they thinking that if you go back up to 1" right away not much reduces?

 

[Sponsor]

 

[uscpsycho]

They sent me this chart and graph that show how much the pressure will be reduced based on how many gpm you are using.

Does this seem acceptable in everyday use? I have four bathrooms plus four more sinks and there will probably be a 5th sink in the backyard at some point.

 

[uscpsycho]

Anyone?

Anyone think I'm going to notice a drop in pressure by installing this? Terry is right, it will go right back to 1" as soon as it gets past the monitor so maybe the pressure drop is minimal. I hadn't thought of it that way but it makes sense.

I've been holding onto it for a while, not sure what to do but the return window is closing so I need to either install it or return it.

 

[Reach4]

Probably would not notice. The higher your supply pressure, the more inconsequential it will be.

 

[Jadnashua]

A short pipe reduction doesn't have as much impact as a longer one. The Bernoulli principle says that a fluid going through a short length restriction will speed up, and then slow down after things expand again, with minimal losses. It all depends on how much restriction and how long. Same sort of thing that happens with a carburetor jet.

Yes, there will be a reduction in volume available. You probably won't notice, but it is measurable.

 

[uscpsycho]

Thanks guys. What Reach4 said (The higher your supply pressure, the more inconsequential it will be.) got me to measure my water pressure. It is 60 psi.

According to what Moen told me, at 60psi I can get a max of 32.6 gpm. And according to the chart above, at 32-33 gpm I will lose 7.8 psi which puts me at 52 psi.

Based on a lot of websites (including several threads here) 50 psi seems to be a sweet spot, so even if I am maxing out the flow rate I will still be above 50 psi.

If I am understanding this right, I should be totally fine under all circumstances. Correct? What I don't know is if 32.6 gpm is a reasonable limit. It seems like it to me, I can't imagine a situation where I'm blowing through that much water. Is there a scenario where a home would exceed that?

 

[Jadnashua]

It's possible, but not likely. If each of those bathrooms also had tubs, and you were trying to fill them all at the same time, someone was doing laundry, dishes, and watering the lawn...yes.

One additional thing to keep in mind is the maximum velocity of the water flow recommendation for the type of pipe you choose. For example, on copper, the maximum velocity recommended on hot is 5fps, and 8fps with cold. The volume that provides depends on the size of the pipe. on 1/2" copper, 5fps equates to only 4gpm which doubles if you go to 3/4". Different pipe materials have different maximum flow velocity that is recommended for it.