PEX Manifold Placement?

[mcintoshmc]

I am in the planning phase of my PEX re-pipe, and have a question on Manifold placement.

I live in one-story single family home 4 bedroom 2 bath

How far can the manifold be from the water heater?

The home is about 45 feet wide running North/South. The water line in is on the North side of the home. The water heater, backyard Spigot (sprinklers) and MAIN bath room is on the North side as well, but the Kitchen, washer/dryer, and 2nd bathroom are on the South side.

I've always heard that the Manifold should be near the Water Heater, but what is near? if I put the Manifold on the North side, the longest runs would be to the Kitchen, etc...If I put it on the south side, it would be more convenient i.e. less work to run the lines, since the majority is on the south side, but it would be some distance from the water heater, and the main bath.

So, how far is too far? I don't have a large home, so I'm hoping placement isn't be an issue.

If I were to put it on the southside, then it would be a 29 foot run to the water heater, and a few feet longer to the MAIN bathroom. Yet, if I put it on the North side, then it would be a 29 foot run to the kitchen, etc..and be a lot harder to run the lines.

What are your thoughts?

 

[johnjh2o]

With the manifold close to the heater there would be a shorter 3/4" hot water line feeding the manifold. Having a longer 3/4" hot line feeding the manifold would require you to run more water before the hot water reached the manifold. Even though the hot water runs from the manifold to the fixture would be longer it would be through smaller lines wasting less water. Of course this is assuming you are installing a home run system.

John

 

[mcintoshmc]

Yes, I'm running HR system. So, basically you're saying that the shorter the run to the water heater, the faster the water will heat up no matter the run to the fixture because it is a 1/2 in line?

 

[johnjh2o]

Most home run systems use 3/8" lines from the manifold to the fixture not 1/2".

John

 

[mcintoshmc]

The water heater is in a hallway closet. Can the manifold be in an access panel sharing the same wall on the other side of the closet in a bedroom? I'm thinking about the heat

 

[mcintoshmc]

"All outlets are individually fed from a common manifold or two central manifolds (hot and
cold). Because inline fittings are eliminated, pressure losses along the line are reduced, allowing
the piping size to be reduced for certain fixtures. Three-eighths-inch piping may be used for
lower flow applications and 1/2-inch piping is recommended for higher flow applications."

What is considered low and higher flow?

 

[johnjh2o]

Just about all fixtures today are low flow. There are flow restrictors on lav, kitchen, and shower faucets. They're not required on tubs that can't be used for showers. In a residential house I would use 3/8" to everything other than the outside faucets.

John