New fittings installed in minutes

DIY: SharkBite Fittings Make Adding a Check Valve Easy 4

If you’ve read any of my previous plumbing DIY posts, you know I’m a fan of SharkBite slip-fittings. Yes, they’re more expensive than standard copper or CPVC fittings, but their primary benefit is how easy they are to install… and remove for re-use or reconfiguration. Normally, you don’t have to remove plumbing fittings often (if ever), but today I needed to, and the SharkBites turned what would have been at least an hour-long job into a 5 minute one.

Because I didn’t want heated (and therefore higher pressure) water flowing out the cold side of my water heater, I decided to install a check-valve “downstream” of the shutoff valve feeding the tank. And because adding that valve would extend the length of the plumbing that feeds the tank, I wanted to throw in a 90 degree elbow fitting to make connecting the stainless steel hose less cumbersome.

Here’s the “before” photo, which I stole from my own How to Replace Your Water Heater post:

From right to left (following the flow of water), you can see the SharkBite shutoff valve, then a T-fitting for attaching the expansion tank, then another T-fitting for the pressure gauge, another T-fitting for the vacuum breaker valve, and then a fitting to connect the CPVC pipe to the threaded end of the stainless fill hose. Had all those fittings been traditional copper, I’d have had to use a torch to remove them, clean up the pipes, and then add in the new fittings with solder. Instead, with a few inches of leftover CPVC, a pipe-cutting tool, and my two new SharkBite fittings, I was able to switch to this in about 5 minutes:

New fittings installed in minutes

New fittings installed in minutes

Fittings from right to left are now shut-off valve, T-fitting for vacuum breaker valve, check valve (new), T-fitting for expansion tank, T-fitting for pressure gauge, 90 degree elbow (new), and 1/4″ to male thread fitting.

Note that when adding a check valve into the mix, the order of the fittings is important. I had to move the vacuum breaker valve from the end of the line so that it was “upstream” of the check valve. Otherwise, the vacuum breaker would have been useless, since any upstream vacuum would have been “blocked” by the check valve. With the way it’s installed now, a massive upstream vacuum (like a fire truck using a hydrant) will still be intercepted by the vacuum breaker, while the check valve prevents heated water from the tank from migrating into the house’s cold water pipes. It’s also important to make sure the expansion tank is “downstream” of the check valve, otherwise it would also be “blocked” by the check valve and unable to perform its job of temporarily relieving tank pressure when needed.

The system seems to be working fine, but as with any plumbing project, I’ll need to check on things throughout the day to make I didn’t create any unexpected issues by changing the configuration (leaks, pressure problems, etc.).

Professional plumbers may balk at the SharkBites, and prefer to crank up the torch and go old school. But for those of us who are amateur DIY guys, time saving gadgets like SharkBite fittings are worth their weight in gold… or at least copper. 🙂

As always, I welcome your questions, comments, and feedback below!


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  • Philip Ngai

    Do you have any means of supporting the weight of the expansion tank?

    • Hi, Philip. I generally use a metal strap, and “cradle” it from the ceiling.

  • Ian Stevens

    Nice! They also make a sharkbite T that has the 3/4 FPT so you can screw the tank directly in to the T. I am going to use the slip T version of that to install an expansion tank in the line going to my hot water heater. Then I will have straps on either side of the T going up to the floor joists to support the weight of the tank.