Dave Yates: The doctor is in

How to become a psychologist and therapist in one easy lesson: Open a mechanical contracting firm! With absolutely no disrespect intended towards those who are degreed in those professions, mechanical contractors and their employees offer practical solutions to issues that vex customers. They remove stress, anxiety and pamper customers with indoor comfort, sanitary plumbing and, in many cases, reduce their operating expenses while providing superior service.

The ailments

“Our second floor (where the bedrooms are) is 10° warmer in summer, and we must crank the AC down so far to sleep comfortably that you could hang meat on the first floor!”

If I had a dollar for every time I’ve heard that complaint, I’d be writing this column from my private island in the Caribbean. Before inverter mini-splits, we had fewer options. Those options included adding the proper return airflow from the upper floor well above head height with a summer/winter damper, which is seldom feasible, and installing zone dampers and daisy chaining them together by zone while adding a zone control panel and thermostat(s) with wireless thermostats, making this far easier to accomplish. And, while we haven’t used any yet, I have seen ads for motorized supply registers, but they weren’t inexpensive and you will need a bypass relief damper if more than a few are installed.

Are your techs, or you, missing an opportunity to be the doctor that cures the issue(s) driving your customer(s) batty?

Customers often experiment before calling in a pro by closing off registers to force additional cooling to the areas adversely affected by a lack of enough return air or unbalanced air distribution because the installer failed to properly size the distribution duct system. This, in turn, often reduces airflow to a point where the coil surface temperature dips below freezing, and the coil becomes an ice ball. A savvy tech will know to look beyond a filter change to ask questions and/or gain permission to check registers throughout the home. Are your techs, or you, missing an opportunity to be the doctor that cures the issue(s) driving your customer(s) batty?

“Our multi-story apartment building has a heating issue. On the north side, the corner bedrooms are substantially cooler, which has generated numerous complaints and has cost us tenants.”

In this instance, you’re faced with baseboard hot water that runs the perimeter of each apartment. The maintenance crew has moved thermostats to the corner bedrooms, which resulted in the rest of the apartment being so hot, the tenants started using the double-hung zone valves (windows) to regulate comfort, which drove up gas usage and had the complex owner chewing them a new rear, so the thermostats were moved back. They closed off the dampers along the top of the baseboard sections, but that had little affect and the bedrooms remained frigid.

The cure? Install a TRV (thermostatic radiator valve) to control the living areas, add a bypass ½-inch copper line run from upstream of the new TRV and reconnect it where the baseboard first enters the bedroom and relocate the thermostat to the bedroom. When the adjustable TRV closes due to the living areas being at comfort conditions, hot hydronic water continues to surge through the ½-inch bypass line, delivering thermal energy to the bedroom until the thermostat is satisfied. A Manual-J calculation will reveal if the bedroom baseboard will offset the heat loss on a design day. If not adequate, you can either install high-capacity baseboard or add a wall panel radiator. Oh yeah, that problem can be solved! You’d better be right the first time because now you’re in the crosshairs. If you’re wrong, they continue losing tenants.

“We had radiant heating installed in our new addition, but it doesn’t work. During cold weather we can’t get room temperatures above 55° F.”

The installer is refusing to come back and has given up. There is a crawl space and the joist bays are insulated, so that should be driving Btu up through the stone-tiled floors. Nobody knows which of the many installation methods was utilized for the under-floor tubing. Water is leaving at 180° and returning at 175° — yikes! Off you go into the cramped crawl space to pull down some of that delightful Pink Panther itchy scratchy you-can’t-touch-it-without-being-infected insulation. Lo and behold, the installer went cheap and utilized the poorest performing staple-up method. He failed to tell the insulation contractor a 2-inch air gap is required, and that guy packed the insulation tight to the underside of the floor — all R30 of it — because more is better, right? R30 out, extruded aluminum plates installed, tubing snapped into the C-channels, R30 back in because now you can pack it in with contact because the plates will spread the comfort and transfer those Btu to the tile flooring — say, “Aaaahhhh.”

The hydronic water temperature can now be lowered to a mere 118° on a design day, which enhances comfort and reduces operating cost. The missing outdoor reset sensor — we don’t need no stinking sensor to operate at 180° — was added, boiler programmed, and the ills were cured.

Via email: “Please help. We have a new home with hydronic heating and four zones. During really cold weather, and this only happens in the middle of the night, we hear what sounds like a shotgun blast that shakes the whole home. I’m an ER doctor and cannot have my sleep interrupted. My wife and children are afraid to go anywhere near the boiler room.”

Like a moth to a flame. Figuring a likely culprit would be delayed ignition, the boiler was the first thing checked, and although combustion wasn’t checked by the installer, it wasn’t too far out of calibration. Ignitor assembly was OK and light-off was smooth as silk. Why the middle of the night, I wondered, and why only on bitter cold nights? “Think,” as Pooh Bear would have said.

There were three Taco 007 circulators installed, standing on their heads like pretty little maids all in a row. Hydronic water pressure was just a bit less than 20 psi. Induction circulators run hot — hot enough to burn upon touching and these three were no exception. Think, think.

Water, under pressure, can be heated well above the normal 212° before it will boil. Superheated water (above 212°) at a fixed pressure will only accept so much thermal energy before it suddenly flashes over into steam. Precisely why water heaters used to violently vacate buildings before Watts developed the T&P (temperature and pressure) relief valve, which conveniently fails open if it sees 210°, thereby preventing superheating water contained inside the vessel. By now, you know where my thought process was headed, but I needed someone smarter than me to confirm the diagnosis. I contacted the engineers at Taco, they worked out the calculations and responded the diagnosis was correct. Three new Taco 007 circulators, orientated to the preferred horizontal position, were installed which prevented any more middle of the night shotgun blasts to disturb the patients’ sleep.

You’re already in their home. They asked you in and a level of trust already exists. The doctor is in the house! Provide the therapy you know they need.