January 30, 2023 - Page 4

The HVAC side of things. We’ve got three different systems here. We have the refrigerated air system, the in-floor heating system with 8 zones, and the Hot Dawg heater in the garage. We replaced all of the thermostats with Honeywell T9 smart thermostats and the Control-by-Web X-300

Here is the upper mechanical room. The boiler heats both the in-floor loops and the domestic hot water storage tanks. These tanks have heat exchangers in them. The circulating pumps for the storage tanks are right behind them and can’t be seen easily. We still don’t know how the boiler does it, but the loops for the domestic hot water run at about 180°F and the in-floor loops run at about 110°F

The hydro separator removes air from both the in-floor and domestic hot water loops.

A close-up of one of the TACO controllers. The T9 smart thermostats needed to have a “C” wire connection, which dumb thermostats don’t need and hence didn’t exist. Fortunately, the TACO controller has the “C” connection in its terminal block, as you can see. Also fortunately, the plumber had used 4 conductor cables everywhere so we had two extra wires available. Since green always means ground, we used the blue wires, which is an unofficial standard. This wasn’t much fun, all the copper around these controllers was hot and the space was tight. We had to unwrap the green and blue, strip the blue, and connect them to the terminal block. For some strange reason, Martin has screwdrivers that fit terminal blocks…

Of course, it couldn’t be that straightforward! Oh, no, the last T9 we installed, in the pool bath didn’t work. The “C” wire was cut somewhere. We searched through all the rough-in photos and couldn’t see where it was cut. We couldn’t find it. The pool bath is close enough to the upper mechanical room that we thought we just might be able to run a new cable. Then Martin spotted it! In the top photo, there’s a bubble labeled “Problem”. The pool bath cable was cut right there for some reason and, of course, only the required red and white had been wire nutted back together. Once Martin reconnected the blue wire the last thermostat worked!

The X-300 web page. It controls the entry way in-floor zone and the refrigerated air and the blower in the air handler.

The “Hot Dawg” garage heater and its T9 thermostat.

The Residio app showing all 8 thermostats