Bob and Tim are driving to a new customer site where there is a complaint of the building not maintaining the correct temperature. The system is a 50-ton air cooled chiller mounted on the roof. The weather is very hot, 97°F, and the indoor conditions are 78°F. The thermostat is set for 75°, and it is late afternoon.
For the quick, cut to the chase version, turning the adjustment on the bottom of an adjustable valve clockwise equals higher superheat while turning it counterclockwise equals lower superheat. However, before you start messing with the adjustment, I suggest you read on.
Subcooling can be a somewhat difficult topic for new technicians starting out in the industry. In fact, few topics garner as many questions from green techs than subcooling does.
Bob and Tim have just repaired a leak on a 10-ton commercial air conditioning system and are ready to charge the unit. The system has a thermostatic expansion valve (TXV) for the evaporator.
Your role in this month’s troubleshooting situation is providing a second opinion on a failed compressor diagnosis. The customer’s complaint is that the unit isn’t cooling properly — the equipment is a heat pump package unit that is just past the warranty period for the compressor.
One of the main components of any refrigeration or air conditioning system is the condenser. As its name indicates, the condenser condenses refrigerant vapor sent to it from the compressor. However, the condenser also performs other important functions, too.
System design, performance, and service conditions must be evaluated when retrofitting with a zeotropic or near-azeotropic refrigerant blend. Always follow the refrigerant manufacturer’s retrofit guidelines before retrofitting with any refrigerant, or system performance could be affected and/or injury may occur.
The Modular Silicon Expansion Valve (MSEV) from DunAn Microstaq (DMQ) is a fast-responding electronic expansion valve that can be used in a variety of refrigeration applications, including display cases, freezers, and walk-in and reach-in coolers.
Measuring the evaporator’s superheat value is an important part of analyzing a system’s performance. If a lower-than-normal value is measured, too much refrigerant is entering the evaporator for the heat load. If a higher-than-normal value is measured, too little refrigerant is entering the evaporator for the heat load.