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Direct fired instantaneous water heaters shall be equipped with a thermostatic mixing valve or valves. A pressure relief valve shall be installed on or adjacent to the heater. A temperature and pressure relief valve shall be installed on the tempered line with the temperature sensing element immersed in the tempered water pipe as close as possible to the mixing valve.
Heat exchangers using a toxic transfer fluid or having conditioning chemicals in the system shall be separated from the potable water by double wall construction. There shall be an air gap open to the atmosphere between the two walls. No heat exchanger will be permitted on any boiler system operating in excess of 65 psi (448.2 kPa), or high temperature hot water system operating in excess of 250°F (121°C), or any steam boiler operating with a pressure in excess of 50 psi (344.75 kPa), unless:
1. The heat exchanger is double-walled;
2. The heat exchanger has an air gap open to the atmosphere between the two walls; and
3. The heat exchanger has a pressure gradient monitor system with a "fail-safe to off" switch installed to isolate the heat exchanger from the potable cold or hot water system. If pressure on the potable water side reaches less than 20 psi (137.9 kPa) above the pressure of the transfer fluid or steam, and a pressure reducing valve is installed on the inlet to the heat exchanger with a setting of 20 psi (137.9 kPa) lower than the potable water pressure at the heat exchanger, an audible alarm shall be activated and the heat exchanger shall be automatically shut off until the alarm and the heat exchanger can be reset manually. Any boiler using toxic chemicals shall have a label with a minimum size of 5 inches by 5 inches (125 mm by 125 mm) attached to the boiler in a conspicuous place. The label shall read as follows:
WARNING Chemicals and additives used to treat the boiler feed water in this boiler are not approved for potable water. The steam or hot water produced by this boiler is not potable. If the steam or hot water produced by this boiler is used to heat water, the water will not be considered potable if the steam and potable water are mixed. |
Water heaters shall be installed in accordance with the manufacturer's instructions. Gas and oil-fired water heaters shall conform to the requirements of this chapter and the Chicago Mechanical Code. Electric water heaters shall conform to the requirements of this chapter and the Chicago Electrical Code.
(Amend Coun. J. 10-14-21, p. 37722, Art. V, § 3)
No direct fired water heater shall be installed in any non-private garage (as defined in Chapter 14B-2).
(Amend Coun. J. 4-10-19, p. 100029, Art. XVI, § 11)
Water heaters may be installed in closets located in sleeping rooms or bedrooms provided that the closet is equipped with a weather-stripped, self-closing, solid door and all air for combustion and dilution is obtained from the outdoors.
Areas containing a water heater shall be provided with an opening and unobstructed passageway large enough to allow removal of the water heater. The passageway shall not be less than 30 inches (762 mm) high and 22 inches (559 mm) wide and not more than 20 feet (6.1 m) in length when measured along the centerline of the passageway from the opening to the water heater. The passageway shall have continuous solid flooring not less than 24 inches (610 mm) wide. A level service space at least 30 inches (762 mm) deep and 30 inches (762 mm) wide shall be present at the front or service side of the water heater. The clear access opening dimensions shall be a minimum of 20 inches by 30 inches (508 mm by 762 mm) where such dimensions are large enough to allow removal of the water heater.
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