# 45 vs 90 degree elbows?



## Ultrarunner2017 (Oct 1, 2008)

Hi;
I have to replace a section of 3/4" pipe which is the main from the meter to the rest of the house.
I am thinking that I should use two 45 elbows for each of 3 bends instead of one 90 each. Reason being that 45's produce less turbulance in the flow, thus more quiet and possibly less pressure drop in the system.
Is this true, or should I just go with 90 elbows?

These are going to be solder fittings.

FW


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## JDC (Mar 11, 2008)

90s. You're not going to notice any difference if you use 45s. You COULD use long sweep 90s (they do make 3/4 copper long sweeps) but again, you're not going to notice any less turbulence or noise.


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## Ultrarunner2017 (Oct 1, 2008)

JDC said:


> 90s. You're not going to notice any difference if you use 45s. You COULD use long sweep 90s (they do make 3/4 copper long sweeps) but again, you're not going to notice any less turbulence or noise.


Thanks for that info. It's half the work with the 90's anyway<g>

FW


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## majakdragon (Sep 16, 2006)

I agree. In a drainage line, 45's are better since they help prevent clogging. In water supply lines, you won't notice a difference and will be doing more work, spending more money and adding potential joints for leaks.


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## Ultrarunner2017 (Oct 1, 2008)

majakdragon said:


> I agree. In a drainage line, 45's are better since they help prevent clogging. In water supply lines, you won't notice a difference and will be doing more work, spending more money and adding potential joints for leaks.


That makes sense.
I did use two 45's in one place but decided against them elsewhere for the very reasons you mentioned.

FW


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## Ultrarunner2017 (Oct 1, 2008)

OK, here's a related question:
What if I have a 3/4" Tee. The supply comes into the center and branches to the hot water heater and the basement bathroom on one side, and to the laundry and kitchen on the other.

When I replaced this Tee, I changed the configuration so that the supply comes into one end, the line to the water heater, etc is straight through, and the laundry & kitchen branch is now on the center of the Tee.
The pipe to the laundry is reduced to 1/2" further down the line, and remains 1/2" the rest of the way.

My thinking was that by having the more important branch connected straight through the Tee, it would have "priority" if both lines were using water simultaneously, leaving more water for the hot water heater and the bathroom.
This of course assumes that the kitchen and/or laundry are only using cold water.

If either of those are using hot and cold, then the flow has to go through both lines. I don't know enough about fluid dynamics to do the math, but it's complicated, isn't it?

Any thoughts?

FW


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