User manual HONEYWELL DU145

[. . . ] DU145 AUTOMATIC BYPASS AND DIFFERENTIAL PRESSURE VALVE WITH DIFFERENTIAL PRESSURE INDICATOR PRODUCT DATA Application The DU145 automatic bypass and differential pressure valve is used to maintain constant differential pressure in a heating system. [. . . ] In addition, when radiator valves are closed it also maintains flow over the temperature sensor on the boiler to ensure proper operation of external temperature compensating controls. On gas fired water heaters it guarantees a minimum flow circulation when thermostats or radiator valves are closed. Features · Simple installation between the flow and return pipework DU145 - 3/4 A DU145 - 3/4 E · Minimises flow noise · No external controls required · Differential pressure finely adjustable · A turn of the adjuster knob is all that is required to set the differential pressure required. · The setting is directly read on the indicator scale · Hinders boiler corrosion Design The bypass and differential pressure valve comprises: · Housing - Version A with fittings - Version B with internal threads · Setting value is in meters water column · Tried and tested Range of Application For pumped hot water heating systems · Spring bonnet · Adjuster knob with setting indicator scale · Valve disc · Spring Specifications Medium For system capacities up to approximately Operating temperature Operating pressure Differential pressure Hot water 70 kW (60 000 kcal/h) max. 3, 0 bar (43, 5 P. S. I, ) Adjustable between 0, 1. . . 0, 6 bar (1, 5. . . 8, 7 P. S. I) Set during manufacture at 0, 2 bar (2, 9 P. S. I. ) Connection size 3/4" Materials · Unpolished pressed brass housing · Brass fittings (Version A) · High-quality synthetic material spring bonnet · High-quality synthetic material adjuster knob · High-quality synthetic material valve disc · Stainless-steel spring · EPDM seals Copyright © 2001 Honeywell AG · All rights reserved EN0H-180GE25 R0301 DU145 Function At equal pressure between the inlet and outlet side the valve is closed. If there is a pressure difference between the inlet and outlet sides, then a force is exerted on the valve disc and against the spring. If this force exceeds the force of the spring, then the valve begins to open in proportion to the rise in differential pressure and maintains a constant bypass flow as indicated on the flow diagram. Versions DU145 - 3/4 A DU145 - 3/4 E = with threaded union connectors R 3/4" = with internal threads G 3/4" DU145 - 3/4 A DU145 - 3/4 E Part No. [. . . ] DU145 can be installed: · On heating systems with three-way mixer valves · On heating systems with four-way mixer valves · On gas-fired hot water circulation heating systems Flow Diagram Honeywell AG · All rights reserved 3 EN0H-180GE25 R0301 Turns DU145 Home and Building Control Honeywell AG Zu den Ruhrwiesen 3 D-59755 Arnsberg-Neheim EN0H-180GE25 R0301 Phone: (49) 2932 9880 Fax: (49) 2932 988239 mng@honeywell. com 4 http://europe. hbc. honeywell. com Subject to change · All rights reserved [. . . ]