MOP Expansion Valves if a MoP (maximum operating pressure) valve is used instead of a standard expan sion valve, the aim is to avoid excessively high evaporating pressure. MoP valves are particularly common in deepfreeze systems, since deepfreeze compressors have smaller electric motors than normal refrigeration or air condition ing compressors and they protect against motor overloading. the only technical difference between a MoP valve and a standard valve is the lower bulb charge in the former. if the entire bulb charge evaporates at a certain temperature, the bulb pressure does not i increase much (or only increases to a negligible extent) beyond this point. this means that the force acting on the expansion valve diaphragm from above no longer increases beyond a certain evaporating temperature/pressure, but the force acting on the diaphragm from below goes on increasing. this puts an upper limit on the evaporating pressure. e.g. at a room temperature of +10°c, a MoP valve with a MoP point of 10°c continues to evaporate at 10°c, whereas a standard valve would evaporate at 0°c. When working with these valves in prac tice, it is important to remember that MoP valves in particular can reach higher super heats without malfunction. MOP charge Standard charge For a free copy of the fitters notes, please return the reply coupon attached or visit: http://www.danfoss.com/BusinessAreas/RefrigerationAndAirConditioning/EducationAndTraining/Fitters+Notes.htm to view or download the Fitters Notes handbook from our website. Danfoss in general Quick Selection Catalogue Danfoss introduces a new catalogue covering the complete RA range: mechanical and electronic controls, compressors and condensing units. This Quick Selection Catalogue enables you to identify and select Danfoss components from all product classes in a quick & easy way. the full colour catalogue in local language contains 204 pages and a summary of the most popular products from our standard ranges of commercial controls, some industrial refrigeration controls, stand alone electronic controls, compressors and condensing units. the catalogue is designed to help you find quickly what you want. With 75 years experience of designing and manufacturing refrigera tion controls, we are able to offer a wide variety of application specific controls. for each of the product types included, you will find an overview of applications, features and advantages together with an Xray picture showing you some unique danfoss features. on the right hand page, you will find a condensed table with the tech nical specs for the most popular models. the foundations of the QSc are strong: the QSc development is based on a modular system so the data can be used for multi ple purposes. With this, we hope to offer a new and important tool, to further improve our service and availability. If you wish to receive a copy of this catalogue, please return the reply form attached or contact your local wholesaler.