When you do it yourself, you walk away with some learning experiences. 

SharkBite Correction: In January, I wrote a piece on copper pipe and fittings. In the article I touched briefly on SharkBite fittings and incorrectly stated that they were only available in sizes up to 1-1/4 inches, which is not true. I misread the literature on the website. The manufacturer's commercial line is available up to 2 inches in size and is rated for 200 psi, so these fittings are not just a residential product as I surmised. They are certainly a fine commercial alternative for piping 2 inches and less. My apologies go out to the people at SharkBite for misinterpreting its literature.

Moving along, over the holidays I visited my brother in the Bay Area (Danville) and was impressed by his instant hot water dispenser. I never really envisioned a need for this particular appliance, but when he created French press coffee in a matter of minutes, it made me quite envious. It takes me the better part of 20 minutes to boil water; that’s time I can ill afford at 5:30 a.m. when I am trying to get out the door for work.

When I came home, I looked at my kitchen granite and was reminded that due to a planning blunder, I had a spare hole in my counter between the dishwasher airgap (a useless fitting in my opinion) and the faucet. “Hmmm,” I thought. “I bet I could fit an instant hot water dispenser in there.”
I did a little research and found a reasonably priced unit that worked well aesthetically with my sink faucet and decided to take the plunge (with the benefit of the contractor’s discount).

I am a big advocate of the do it yourself (DIY) mentality. I have made this comment in the past and been criticized about unions and licensure and permits, but my understanding is that anything downstream of the rough plumbing is fair game for DIY since it doesn’t require inspection, but surely many would disagree.

So, assuming that installing an instant hot water dispenser downstream of the existing roughing breaks no laws, which I would argue that it does not, I ventured forth. 

In my opinion, each of us in this industry should pursue at least one project of this nature. Field visits are essential as well, to witness the installation of the piping that we design, but it is not until you get underneath the sink and put wrench to fitting that you really understand all the details of what our field brethren have to deal with.

The hot water dispenser came complete with all the fittings and hoses necessary for the installation except for one. A tee fitting is required in order to tap into the cold water supply connection downstream of the cold water supply stop. Why they don’t include this one fitting is beyond me, but there it is. It is shown circled in red in the image to the left.

Purchasing this fitting was a little tricky. On my first trip to the hardware store, I bought a 3/8 x 3/8 x ¼-inch compression tee. This didn’t work, because the outlet of the CW supply stop is male, and it didn’t work with the compression connection on the tee. What I needed was a 3/8-inch female compression by 3/8-inch male compression by ¼-inch compression tee, so a second trip to the hardware store was required. Once I had the right kind of fitting, the installation was a breeze (I have noted in the past that every home improvement project can be ranked in difficulty by the number of trips required to the hardware store, so this one ranked a 2 in terms of difficulty.)

In going through the exercise of this DIY project, it really punctuated the level of detail the guys in the field need to execute when installing plumbing systems. For a large project, think of the enormity of fittings, nuts, bolts, valves and so on that have to be ordered properly to finalize the installation. It’s quite remarkable actually.

Further on the water heater, notice in the diagram that the heater has three hoses coming off the top. On the left is the cold water inlet. In the middle is the hot water outlet. On the right is what they call a vent. I’m not sure if this is an air vent, or if it is the pressure relief connection. I do know that these units have internal pressure relief valves, and they relieve themselves through the faucet fitting into the sink. This might be the hose on the right, or it might use the hot water supply as the relief. The literature didn’t say. Regardless, it’s important to note that these units do not require a floor drain for the pressure relief.

“Isn’t that dangerous?” you might ask yourself. We never spill a relief valve to a kitchen sink, so why would it be allowed here? I guess the rationale is that the faucet is intended to dispense near boiling hot water, so if the relief were to discharge it would be little different than the ordinary use of the fixture. You just wouldn’t want to have your hands underneath the faucet if it were to happen unexpectedly, but this is not the kind of faucet you would normally put your hands below. 

With the installation complete, my sons can now easily make a cup of instant coffee, hot chocolate or noodle soup. I find the device handy as well for rinsing off utensils that you want to reuse while cooking, or getting baked-on food off pans or plates, and, in the process, I learned a little about the necessity of detailed specificity when purchasing something as simple as a tee fitting. Like they say, the devil is in the details.

Timothy Allinson, P.E., LEED AP, is vice president of Engineering at Murray Co., Mechanical Contractors, in Long Beach, California. He holds a BSME from Tufts University and an MBA from New York University. He is a professional engineer licensed in both mechanical and fire protection engineering in various states, and is a LEED accredited professional. Allinson is a past-president of ASPE, both the New York and Orange County Chapters. He can be reached at

Content Type: