USDT 2004 Differential Controller - Thermomax Technologies

IntroductionNote: The information supplied in this manual is for guidance only - no part ofthis may be used for any agreement, whether express or implied, or to form anycontract. Thermo Technologies reserves the right to change specificationswithout prior notice.T he USDT 2004 unit is a powerful temperature differential controller. It canbe used in a wide range of applications. At the factory, it is set to controla simple solar water heating system. In this program mode, PROGRAM 0,USDT2004 ensures that the collected energy from the sun is transferredefficiently, and harnessed under optimum conditions. It monitors the collectortemperature (T 1 ) and the return temperature (T 2 , bottom of the storage tank). Thesolar loop circulation pump runs while the collector temperature exceeds thereturn temperature by a programmable temperature difference DELTA T. Toavoid overheating, the circulation pump stops if the collector (T 1 ) temperaturereaches the programmable high limit (T MAX ) temperature. To prevent freezing, thecontroller activates the pump and circulates water through the solar loop whenfrost conditions exist. The temperature hysteresis (a lagging in the set-point) mayover-ride DELTA T and can be modified in advanced operation mode to avoidpump cycling. You may measure the temperature of the storage tank (T 3 , top ofthe tank) using the third sensor in the program mode 1, PROGRAM 1.The control unit has the following functions:• 2 inputs for temperature sensors• 1 input for flow rate measurement or additional temperature sensor• Can be used as BTU meter for constant flow rate or in concert with a flowmeter• Suitable for sensors of type Thermistor and PT1000• All hysteresises are adjustable and depend on temperature• Adjustable (-3 o F to 41 o F) frost protection• Adjustable (200 o F to 299 o F) overheating protection• Adjustable (4.1 o F to 99 o F) temperature difference DELTA T• Manual override of pump for system testing• Digital display of all parameters• Indications of current state of pump• System status and diagnostic displays• Collector sensor surge protection2