Thermal traps for combustion air inlets

Many residential mechanical rooms have rigid metal ducts to pull combustion air into the space for safe operation of the gas-fired equipment. Often the water piping for domestic water lies near the air inlets, posing a potential for freezing in our cold Colorado winters. I frequently see air inlets stuffed with insulation or sealed shut. So in the winter, when the appliance needs to run the hardest, it is starved for air, which makes for an unsafe condition.

I have solved the problem of both freezing pipes and air-starved burners by making thermal traps for the combustion air inlets with two 90° elbows and a small length of straight duct on the end. Skeptical homeowners are amazed at how well the simple trap works; the material costs are low enough to persuade them to try it. Our local inspectors like it, too, but still require that the traps terminate within 1-ft. of the ceiling and floor, per ICC code. The warmer room air stops the cold from falling in but allows makeup air to enter as needed.


Jeremy Graham
Parkey’s Heating and Plumbing
Colorado Springs, Colo.

Easy shower arm installation

I learned this technique from my father in the 1950s. To install a shower arm, I first put Teflon tape on the threads, then turn the arm manually until hand-tight. Then I insert a Channellock pliers handle into the opening of the arm. This gives me an “extension” of the arm to assist in the tightening process. I turn the pliers’  handle to the right while offering resistance on the shower arm with my left hand so as not to torque the pipe.

This method does not hurt the thin shower arm pipe but allows me to always turn it tight enough to be secure. This works every time and eliminates the need for a strap wrench.


Barney Gidders
Gidders & Sons Plumbing
Fairfax, Va.


Basket strainer installation upgrade

How many times have you had to go back into the crawlspace to reset the bath waste overflow or under the kitchen sink to reset the basket strainer? All because the rubber washer is pushed out by the plumbing putty or by overtightening. One day, working alone, I discovered a simple yet inexpensive idea. I replaced my damaged paper washer with my own washer made from a sheet of sand paper. 

I bought a whole box of sand paper, Norton Extra Fine P320 Grit Sandpaper, and I’m making my own washers. This also works while installing a bathtub waste overflow — sand the rubber washer and brass body lightly with 200-grit sandpaper for better grip.


Mark Sonnenburg
Good Plumber
Auburn, Wash.


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