Sanity Saving PEX Manifold Installation Tips
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There were several lessons learned when completing the Uponor PEX manifold in the last post (shown on the right). We collected all of our sanity saving PEX manifold installation tips here so you do not repeat our mistakes. We’ll also dive into the reasoning behind certain steps.
Some of these are specific to our whole house Uponor manifold, while others are applicable to all manifolds–manibloc, DIY PEX, copper, etc.
In no particular order (as they are all worth considering)…
Balance water pressure with a loop on the cold water manifold.
Did you notice the “D” shape on the cold side of the manifold whereas the hotline branches directly into the individual lines? We suggest adding a loop on the cold side to balance out your water pressure.
When you were growing up did you ever yell that your brother when you were taking a shower and he flushed toilet? It didn’t matter if he meant to or not because the end result was the same: the water pressure dropped and you got hit with scalding hot water. The cold water got diverted to his toilet instead of keeping your shower temperature the same.
I STILL jump when I hear a toilet flush when I’m in the shower…
When you add a loop on the cold line you are allowing the system to evenly balance the supply of cold water. Forget hoping your supply line comes before anyone else. With this manifold you are welcome to take a shower, incidentally start the rinse cycle on a load of laundry, and flush the toilet…all at the same time!
End result?
.
.
.
I didn’t hear any shouting…
Why did we not out of loop on the hot side? There is not as much of a demand for hot water.
Add drain spigots.
Next time we plan on adding a drain spigot on the bottom of both the hot and cold lines within the manifold, after the shutoffs. By adding spigots it is easy to shut off incoming water and drain out the manifold.
Note: you want to place the spigots on the bottom of the manifold on the house side of the shutoff.
There are times you don’t want water in the system. What if you want to make a change or repair? It is also a must have for winterizing a house.
In the meantime, another set of couplings are added outside of the manifold cabinet. Installing a washing machine water box is an additional step for this manifold. Next time…
Run and secure the PEX first before making the final connection to the manifold.
At this point all PEX lines should be run to their final connections and be hanging in the wall, ready to connect to the manifold.
You want to secure all the lines throughout the house first so that you are not surprised with any runs that come up slightly short. If that happens you have two choices:
- A hidden coupling in the wall or…
- Rerun the entire line.
Consider the available surrounding space when choosing where to install the manifold.
The obvious answer: if a manifold is placed in a stud wall it will need three adjacent bays. One bay is for the manifold and the next two, to the left and right of the first, are open for plumbing to run from the manifold to the attic.
The not so obvious answer: the available space in the attic in addition to the surrounding wall bays. We are not just talking about left to right. Once the PEX goes up from the manifold it still needs space to curve from the vertical wall to the horizontal attic.
Check out the space above the wall where this manifold is mounted.
Ouch.
That is right where the roof decking meets the top of the wall. In this case, despite the fact that we are using the more flexible Uponor PEX-a, there is still not enough space to run the 3/4″ line in one continuous line without running the risk of kinking.
In this instance it is not possible to move it over one more since there is a doorway. Maybe you have the option of moving your manifold over one more bay in the wall.
Hopefully you are not in the same boat where it is not possible to move it any further. If you can’t, expected to buy a few 90 degree couplings which will be buried in the wall. At least it’s better to know ahead of time instead of waiting on a few “oops” parts.
Centralize the location of the manifold in the house.
If you’re looking at this post you’re probably still in the planning phase. Since you’re running an entirely new plumbing system you can reconsider the final mounting location of the manifold as well as the water heater.
For example right now my water heater is sitting at the far end of the house. This is not a problem for the kitchen and laundry but my master shower is that the exact opposite end of the house. I would rather have a randomly placed cabinet in the middle of my house then waiting five minutes for hot water to make a grand entrance.
If you can move the manifold and water heater closer to the middle of all the action:
- You are conserving water. When we want hot water we pour perfectly good cold water down the drain. With a shorter line; when you shut off the hot water, there is less heated water trapped in the line. Now the hot water stuck in the line will cool off. The once hot, but now cold water will get poured out waiting for hot water to come out again. It’s a great time to fill up your Brita filter, but the Brita filter can only hold so much at one time.
- You are saving yourself time because water gets to the outlet faster. A shorter run from the manifold and water heater means less time waiting for the hot water to come out. Case in point: I refuse to use my master shower in the winter because it takes entire minutes for hot water to get there (there is a replacement PEX run in the attic that warms up nicely in the summer).
- You are conserving energy. The longer the pipeline, the more water the water heater has to heat.
Know the supply line size coming in from the city.
If you are starting from scratch you are probably already at the modern standard 1” pipe. Enjoy this freebie!
Originally, the rebuild inspiring these tips started with a 1964, 3/4″ line coming in from the city. Unfortunately for this build, we discovered multiple issues, which lead to an all out excavation and rerun of lines from the city connection to the house. With the all out replumb outside, it ended up being a 1” supply.
By that point in time the manifold was already waiting to get installed with a ¾” supply leading into the 1” manifolds. Any reduction in size reduces water pressure. Given, this was unexpected and the house has better water pressure than before because of the upgraded 1” supply.
Everything in the circle can now be up sized to 1″. The arrow indicates where the reducing tee expands from 3/4″ to 1″.
This situation is definitely not the norm since this was just one more complication from an unexpected hurricane. If you are looking at a new build you’ll probably already have the maximum supply. Just make sure you know what it is before ordering parts for the manifold.
Pre-plan expansion.
When you are in the planning stage, before you place your order…well before you are soldering, consider any possible needs in the future. Maybe you’ll want an outdoor sink, wet bar area, etc. Consider adding in another jump off both the hot and cold water lines. Then run the PEX up into the attic and cap it off.
This is the time when it is easy to access inside the walls as well–preventing patched drywall if you change your mind in the future. Painting a patch is no fun either…
This manifold has two extra lines: one 1/2″ on the cold side and another 3/4″ on the hot side.
After all your planning and hard work installing a manifold, let’s try to prevent a dent in your pride by missing one of these (now) easily preventable PEX manifold installation tips.
Looking for specifics on how to to build your own manifold? Need a little more knowledge drop on why you want to go this route? Check out these posts to read about more manifold goodness:
