UL 17:2008 pdf download – Vent or Chimney Connector Dampers for Oil-Fired Appliances.
20.2.2 A temperature other than the fluegas temperature is to be measured by a thermocouple not heavier than 24 AWG (0.21 mm2). The temperature attained by a part of the vent or chimney connector damper is to be obtained by means of a thermocouple applied to assure positive thermal contact with the part. Such a thermocouple is to be located at a point attaining maximum temperatures. Additional thermocouples may be placed at other locations as deemed necessary.
20.2.3 The ambient temperature is to be determined by the use of a shielded thermocouple located at the elevation of the honzontal axis of the flue-gas generator and is to be on a vertical line located 24 inches (610 mm) horizontally from one wall of the test structure.
20.2.4 The measurements of temperature rises on the vent or chimney connector damper paris and on the test structure are to be referenced to the recorded ambient temperatures as determined by 20,2.3
20.2.5 A thermocouple is to be attached to a metal surface by silver soldenng, brazing, or welding of the tip (junction) to the nietaJ surface.
20.2.6 A thermocouple is to be secured to a wood surface by staples placed over the insulated portion of the wires. The 112 inch (12.7 mm) length of thermocouple tip is to be depressed flush with the wood surface at the point of measurement and held in thermal contact with the surface at that point by pressure-sensitive tape.
20.2.7 The wiring methods for thermocouple circuitry including junctions, terminals, switches, plugs, and jacks shall be such as to provide independent continuous routing of both thermocouple leads to the recording equipment.
20.3 Temperature measurement on electrical components, thermocouple method
20.3.1 Temperatures of electrical components are to be measured by thermocouples, except that the change-in-resistance method may be used to measure the temperature of motor windings or o4 coils. The thermocouples are to consist of 24 — 30 AWG (0.21 — 0.05 mm2) wires. The thermocouple wire is to conform to the requirements as listed in the Tolerances on Initial Values of EMF versus Temperature tables in the Standard Specification and Temperature-Electromotive Force (emf) Tables for Standardized Thermocouples, ANSI/ASTM E2301E230M,
20.3.1 reved Sipiember 25. 2013
20.3.2 A thermocouple junction and adjacent thermocouple lead wires are to be securely held in positive thermal contact with the surface of the material the temperature of which is being measured. In most cases, thermal contact will result from taping or cementing the thermocouple in place, but where a metal surface is involved, brazing or soldering the thermocouple to the metal may be necessary.
20.3.3 If thermocouples are used In the determination of temperatures in connection with the heating of electrical equipment, it is common practice to employ thermocouples consisting of 30 AWG (0.05 mm2) iron and constantan wires and a potentiometer type of indicating instrument whenever referee temperature measurements by means of thermocouples are necessary.
20.3.4 lIthe terrerature of a motor winding or coil is to be determined by the resistance method, the following formula shall be used:
20.3.5 If it is necessary to de-energize the winding before measuring R, the value of R at shutdown Is to be determined by taking several resistance measurements at short intervals, beginning as quickly as possible altec the instant of shutdown. A curve of The resistance values and the time is to be plotted and extrapolated to give the value of R at shutdown. The motor or coil winding is to be at room temperature at the start of the test.
20.4 Test method
20.4.1 The vent or chimney connector damper and any associated remotely connected control subassembly. if provided, are to be energized at the test voltage specified in Table 18.1 for the corresponding voltaQe rating. Electrical loads that will cause maximum rated current to flow through the current-carrying components are to be connected to the load terminals. Before starting the test, the load-carrying contacts are to be opened and closed under load a minimum of three times.
20,4,2 The connections to the vent or chimney connector damper and the remote control assembly are to be made with conductors of a size as required for 60°C (140°F) rated wire.