Part 40Combustion trim

Part 40—Combustion trim

31 Prescribed activity

The prescribed activity is installing on a gas‑fired steam boiler, a gas-fired hot water boiler or gas-fired water heater that is a Type B appliance and has an electronic gas/air ratio control system capable of receiving a signal from a flue gas sensor for combustion trim purposes, an unlisted product that complies with the criteria specified in column 2 of an item in Table 40.1.

Table 40.1—Product categories

| 40A | A combustion trim system that—<br> (a) includes a flue gas sensor connected to a control panel, capable of sending a signal to a control damper on the burner air supply or variable speed drive on the fan motor; and<br> (b) is designed to be installed on a gas-fired steam boiler, gas-fired water boiler or gas‑fired water heater that has an electronic gas/air ratio control system capable of receiving a signal from a flue gas sensor for combustion trim purposes. |