Document 9LmrLvYrQmq9nQGQY50yyV0BR

C. A. Dunham Company Specialties, Heating Application 1 is & manually controlled Differential SyBtem using steam at not more than 10 lb. initial gauge pressure. For higher initial pressures see Apnlica.tion3. TwoSub-Atmospheric PressureReducingValves are used as shown. Valve "A" supplies steam in mik] weather, lie second valve, "B* supplies steam in cold weather. In extreme weather both valves may be used if necessary. Application ^ is an automatically controlled system on which a temperature controlled valve "C," operated from a thermostat is substituted for valve "B." The thermostat must be placed in a typical room on the most exposed side of the building at the point most remote from boiler measured along the steam piping. The thermostat location must represent the average build ing temperature and beat requirements. Hie tempera ture control equipment may be one of the several com mercial types according to the requirements of the building, when such an arrangement is used the valves should be installed as shown. Application 3 is a manually controlled system on which the source of steam supply b greater than 10 (b. The pressure reducing valve "D" should be installed as shown. ^Application 3 may be modified by substituting a temperature control valve for valve *'B." Sub-Atmospheric Reducing Valves should be located in the piping, so that the Engineer can conveniently stand on the boiler room floor, or control room floor, and from there shift the scale weights wind) vary the Pressure or Vacuum carried in the heating main. The scale weights to be bung on extension rods of)4-in. pipe of proper length bo that weights come 6.fi from the floor. On very large installations it will be of advantage to provide a separate set of Control Valves for each Main Branch so that the heat to each main.portion of the building, can be controlled most economically. A separate pump must be used for each cone. Pressure Reducing Valves can be omitted on low pressure oil, gas fired, and coal fired installations having blower or stoker if each method is controlled by a room thermostat. Drip trope must always be used on drab points of steam mains whenever Pressure Reducing Valves are used. 750 C. A. Dunham Company Specialties, Heating DUNHAM DIFFERENTIAL RADIATOR TRAPS Angie Pattern Straightway Pattern Bight Hand Pattern Left Hand Pattern All traps used in connection with the Dunham Differential Vacuum Heating System are known as "D" series. They function uniformly over a range of pressures and tempera tures from 25 in. of vacuum to 25 lb. gauge pressure. The accompanying chart shows performance of a Dunham Dl Radiator Trap over this range of pressures and temperatores. The outlet temperature in this test bore the same rela tion to the inlet temperature of the radiator over the entire pressure range of 25 in. vacuum to 25 lb. gauge, a pressure sub stantially 37H lb. higher than Sectional View of Dunham Thermoetatic the 25 in. vacu- Radiotor Trap u m. Graph showB the con stant uniformity of temperature between steam and return lines throughout the entire range of pressures. Hie radiator efficiency was consistently high (almost 100 Esr cent and there was no steam leakage or water accumution. The condensation rate in the 5.0 lb. gauge test increased due to air movement in the room and a low room tempera ture, the trap responded immediately by passing the in creased condensate under this condition without leakage of steam. Hie test was conducted on a 3 ool. 38 in.--100 sq. ft. radiator. The Dunham traps conform with the standard dimension of $yi b. from center of trap to end of union nipple, as adopted by The Healing and Piping Contractors' National Aseociation for M b. radiator traps. Float and Thermostatic Traps--"D" Series 25-in. vacuum to 25 lb. gauge pressure. < Sites are distinguished by sixe number preceded by a capital "D." . Trap No. D22 D23 D16 Size of Tffi8 y. 1 v.\ Capacity Sq. Ft. Net Equivalent Wght. Direct Lbs. Radiation 1600 14 2800 15 3600 24 A H'/4 II 'A 14'/, DI7 t1 DI8 l'A . 5200 8000 24 14'/, 33 !5'/2 DI9 11500 33 15'/; D20 2 14000 42 I9J/, Dimensions. Inches B c. D E F G 6V, 9'/. iy. 3'/. '/. sy2 Capacities given are based upon sy. iy A A sy29'/, 3 a condensation rate of lb. per ` square foot of cast iron direct radio- m i<*/2 iy. m,l'/2 tion per hour, at a pressure differ ential of one inch of mercury, which r/t mIO>/2 iy. 4y. l'/2 is equivalent to H lb. per square inch. AU traps have right nand 9'/, 12'/, 2 y24% l'/4 9 female tappings. '/. 12'/, 2 4y4 iy. 9'/2 iy.aM'/s 151/2 2 <% 9'/s