Q&A / 

PEX Water Lines vs Copper and Water Heater Venting

Running AquaPEX

The red and blue pipes will supply hot and cold water to each plumbing fixture in this new home as soon as they’re connected to a distribution manifold inside this closet. (C) Copyright 2019 Tim Carter

PEX Water Lines vs Copper

QUESTION #1: Can you help me make a decision, Tim? I’m building a new home and have the option of using PEX piping for my hot and cold water in the house as opposed to traditional copper. Do you have an opinion about both materials? Have you used both? What do you have in your own home? Linda P., Rocky Point, NC

You may be building a new home or planning a large room addition that will have a new bathroom, kitchen, or some other plumbing fixtures that require hot and cold water. Your builder or plumber may lay at your feet the same decision Linda has to make. I can help you as I’ve been a master plumber since age 29.

The PEX plastic water piping for drinking water has been around for almost three decades now. Plastic PEX piping was first introduced in the late 1960s and its use as radiant floor heating exploded in Europe in the 1970s.

During the early part of my plumbing career, I only installed traditional copper water lines. It was a mainstay in the Midwest. However, the plumbing codes started to permit the use of PEX and once plumbers became comfortable using it, its use started to grow like dandelions in the spring.

I have PEX piping in my own home for both the radiant heating system and all of the hot and cold water that’s supplied to each faucet. It’s important to realize there are different brands of PEX. While the piping chemistry may be the same or very similar, the method you connect the pipe to fittings is different. The one that I’ve come to trust and use is AquaPEX that employs an ingenious expanding compression collar at each end of the tubing to create a leak-proof connection.

Installing traditional copper can be a complex and time-consuming process if you solder the tubing to the fittings. In the past decade, there’s been a shift to connecting copper tubing and fittings with a pressing tool that crimps the fittings onto the end of the tubing without using molten solder. An inner rubber o-ring in a raised collar on each fitting along with the crimping creates a leak-proof joint. I have these press fittings in my own home where the copper water lines connect my modulating boiler to the heating distribution manifolds.

The copper press fitting system saves enormous amounts of time. It only takes seconds to create a leak-proof connection. However, you may have to install quite a few of these press fittings to supply water to just one fixture. PEX piping eliminates all these fittings.

PEX water piping is much like electrical wiring. It’s flexible and you can run long lengths of it from a central distribution manifold all the way to the plumbing fixture without any joints. These long runs of tubing from a fixture to a manifold are called home runs. You can install one PEX pipe in just minutes if your home is framed using open floor trusses. The home run system allows you to turn off the hot or cold water to just one fixture and still have water working at all other fixtures.

The fastest way to install hot and cold water lines in a home or room addition hands down is the PEX piping employing an uninterrupted single pipe between each fixture and the central manifold. To put this in perspective, my son-in-law and I installed all of the hot and cold water lines to his new four bathroom home in less than three hours. You could never accomplish this feat using copper, even with the wonderful press fittings.

I have a video at my AsktheBuilder.com website showing you how fast and easy it is to create one of these PEX connections using the simple expansion compression collars. I suggest you go there and type Connect Pex Pipe into my search engine and watch it. You’ll be astonished at how simple it is to work with PEX water lines.

Water Heater Venting

QUESTION #2: Hey Tim, I need your help connecting my new gas water heater to my chimney. Here’s my deal: My chimney has an 8x8 clay flue liner that’s just under 20 feet from the inlet in the basement to the top of the chimney out on my roof. The water heater vent pipe is 3-inch PVC. The water heater has a 50-gallon capacity with a 40,000 Btu burner. Should I install a 4-inch pipe from the new water heater to the flue liner? Ron D., Boise, ID

Each week I receive lots of email from homeowners like Ron asking detailed questions about exactly how to install any number of building products. I understand I think, why they come to me. It’s easy to ask me, a sales clerk at a store, or even some online home improvement chat group.

However, in most cases, I’m the wrong person to ask and you should be extremely cautious following the advice from others who you’ve not vetted determining the depth of their experience solving the exact problem you face.

When it comes to the nuances of installing products and mechanical equipment like Ron’s new water heater, there’s only one accurate source for your answer: the manufacturer of the product or fixture. The first place to start is by reading the product label or the instruction manual.

In Ron’s case, he needs to understand that the water heater venting system is most likely controlled by a very tiny, yet powerful, computer that’s connected to sensors within the water heater. The vent may have to be PVC from the heater all the way up through the roof or out a side wall. There are maximum lengths the pipe can be as well as the number and types of fittings that can be installed between the water heater and the end of the pipe outdoors.

In other words, stop hoping that something is going to work when it’s installed. Stop hoping if you or your family is going to die from carbon monoxide poisoning. Take the time to read what the manufacturer wants you to do. In many cases, they may have their own installation videos showing you what to do. Remember, if you want to be SAFE and you want the warranty with a product, only do what the manufacturer says to do. Period.

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