Indiana Administrative Code
Title 170 - INDIANA UTILITY REGULATORY COMMISSION
Article 6 - WATER UTILITIES
Rule 3 - Central Station Hot Water Heating Utilities
Section 3-6 - Instrument approval and testing; allowable errors

(a) All recording and indicating thermometers, gauges, or other instruments used by the utility in connection with its central station heating service shall be of a suitable make and type satisfactory to the commission and shall be subject to the following tests:

(b) Recording thermometers, shall be compared at least once per month and indicating thermometers and gauges shall be compared at least twice during the heating season with standard calibrated indicating instruments. The range of the check observations shall extend, so far as practicable, over approximately two-thirds of the working scale.

(c) A record shall be kept of all tests, which record shall contain all the information necessary to identify the instrument, the date of the test, the results of the test and all readings taken.

(d) The error of the indicating thermometers used to indicate the temperature of the water in the station flow and return mains shall not exceed plus or minus 1 degree between 70° F. and 240° F.

(e) The error of the recording thermometers used to record the temperatures of the water in the station flow and return mains shall not exceed plus or minus 3 degrees between 70° F. and 240° F.

(f) The error of the indicating thermometer used to indicate the temperature of the outside air shall not exceed plus or minus 1 degree between -20° F. and 70° F.

(g) The error of the recording thermometer used to record the temperature of the outside air shall not exceed plus or minus two degrees between -20° F. and 70° F.

(h) A record of the indication, at intervals of one hour, of all indicating thermometers required under this section shall be kept by the utility.

(i) Where recording thermometers are used the utility will not be required to keep a record of the readings of the corresponding indicating thermometers.