CHS_LHS

30366461EN-08 10 LU-VE Group reserves the right to change specifications without prior notification. refrigeration process is resumed after concluding the defrost cycle, remaining frost may form sites of solid ice. Such solid ice will increase with every following defrost cycle, and ultimately accumulate up into the drain tray. This inevitably leads to malfunctioning and damage to the cooler. Coolers without defrosting facilities may not be used in room temperatures below +2 °C. Do not use any mechanical devices or any other means to speed up the defrosting process other than those recommended by the manufacturer. 3.15 Electrical defrost Identical elements are used in the finned coil and in the drain tray. Always refer to the electrical scheme for both connections and nominal voltage of the electrical defrost option. Ground cable must always be wired and connected to the appropriate terminal in the connection box. Always refer to the electrical scheme order to identify the ground terminal. Installation of a switch for defrost line is mandatory and is the responsability of the installer. Warning about the neutral wire: it must be connected if indicated in the electrical scheme. It must not be connected if it is not shown in the electrical scheme. 3.16 Electric defrost termination If the cooler is working on a time termination cycle, it is suggested that an initial defrost period be set at 35 to 45 minutes (in combination with the number of defrost periods). This setting is to be refined through trial and error, according to the actual defrost requirements depending on cooler model, size, and working conditions. If the defrosting cycle is terminated via a temperature sensor, close attention must be taken in positioning the thermostat sensor. The temperature sensor is usually set at a value between 10°C and 15°C. In general it should be positioned where the last traces of frost disappear, usually on the coil. At room temperatures of around 0°C the last frost is usually in the top of the coil block. At room temperatures below -20°C, this is the consequence of the so-called 'chimney effect', usually in the lower half of the coil block at approx. ¼ of the fin height. Unfortunately a number of factors (cooler position relative to an access door or stored products, precise setting of the thermostatic expansion valve, etc.) may cause identical coolers to perform differently (see maintenance instructions). Thermostat sensors should NOT be placed in the direct vicinity of a heater element. The final position of the temperature sensors must be determined through trial and error. Î The next cooling cycle may only be started when the coil block has been completely defrosted. 3.17 Water defrost The water inlet and drain sizes are calculated for the water defrost system. The entry and drain lines should be executed with the same line diameters. Success in water defrost lies in passing sufficient water over the coil, as specified by LU-VE Group. In this, generous drain line slopes are essential. Some form of inlet flow adjustment is required. Î A reduced flow rate for a longer period simply does not work! The water distribution pattern may alter drastically, parts of the coil will defrost, and on other parts ice will build up, ultimately threatening the lifetime of the cooler. A clean supply of water is important and it is recommended that a suitable water filter be used in the supply line. 3.18 Hot gas defrost When hot gas defrost is applied, a good hot gas supply must be secured during the entire defrost period. Generally this is two thirds of the defrost time required for electric defrost. The position of any temperature sensor to end the defrost cycle, is where the last traces of frost disappear, usually on the coil. The most important consideration during this process is the matter of condensate removal, since any tendency to log up liquid in the cooler can lead to severe problems. A good downward condensate drain directly from the cooler is essential, and where condensate drain lines rise locally, this must be correctly sized. 3.19 Drain tray insulation It is recommended to apply drain tray insulation for coolers operating at room temperatures below 5 °C and/or with high humidity in the cold room.