Confused about pipe sizing

[Brad Perkins]

Trying to hook up my well to a holding tank in my basement. My plan is to run 100 ft of 1 inch poly to the house. Then on the inside I thought about using 1 inch PEX for everything to tie into my manifold. I can't help but notice how much smaller 1 inch PEX is than 1 inch poly. And since I planned on all PEX inside, I started to wonder about the connection to my submersible in the tank. Should I use 1 inch poly that transitions to 1 inch PEX going into the pressure tank or would it be ok to use 1 inch PEX off the pump too?

 

[Valveman]

Depends on how large your pump is. 1" poly is good for up to about 15 GPM, but you won't be able to put that much through 1" PEX.

 

[Sponsor]

 

[Reach4]

1 inch PEX should be fine for that. https://www.pexuniverse.com/pex-tubing-technical-specs has a nice "Pressure Drop Table (psi per 100ft of tubing length)" table.

I would try minimize the length of 1 inch PEX carrying hot water to the manifold.

 

[Brad Perkins]

I have a 10 gpm pump.

The total length of pipe from the pump to the water heater is around 30 ft. If I used poly just in the tank then I'm only knocking off 5 ft of PEX.

 

[Boycedrilling]

1” PEX is about equivalent to 3/4” poly pipe. You need 1 1/4” PEX to be equivalent yo 1” poly to pvc.

 

[Brad Perkins]

So let's say I go ahead and use 1 inch PEX from the pump to the manifold, that's probably 20 ft of PEX. My hot water tank is 3 ft away from the manifold. I'll also have a water softener plumbed in there too. With a 10 gpm pump set to 50 psi pressure, should that supply my house ok? Think I can still run a dishwasher, laundry and take a shower at the same time?

 

[Reach4]

So let's say I go ahead and use 1 inch PEX from the pump to the manifold, that's probably 20 ft of PEX. My hot water tank is 3 ft away from the manifold. I'll also have a water softener plumbed in there too. With a 10 gpm pump set to 50 psi pressure, should that supply my house ok? Think I can still run a dishwasher, laundry and take a shower at the same time?

7 gpm would probably do that, so 10 gpm will too.

3/4 from the WH to the hot manifold would probably be better.

 

[Brad Perkins]

What's the issue with the water heater placement? 3 ft seems closer than average based on what I've seen.

 

[Reach4]

What's the issue with the water heater placement? 3 ft seems closer than average based on what I've seen.

Yes, 3 ft is good. At that distance, the amount of time it takes to get the lavatory water hot is going to be hardly affected. 1 inch pex holds about 3 gallons per 100 ft.

https://www.pexuniverse.com/pex-tubing-technical-specs

Presuming 1.5 gpm from the lavatory faucet, using 3/4 instead of 1 inch only gets the hot water to the lavatory 3.24 seconds faster for the 3 ft. The long run of 1/2 is what will take the time.