Daikin Enfinity CCW Installation And Maintenance Manual

Daikin Enfinity CCW Installation And Maintenance Manual Manual pdf 16 page image

C ontrolsIM 1049-9 16 www.DaikinApplied.comMicroTech® III Unit ControllerThe MicroTech III Unit Controller includes built-infeatures such as random start, compressor time delay,shutdown, condensate overflow protection, defrostcycle, brownout, and LED/fault outputs. Refer to"Table 7:MicroTech III Controller Status LED's" on page 18.The unit has been designed for operation with amicroelectronic wall thermostat selected by the manufacturer.Do not operate the unit with any other type of wall thermostat.Each unit has a printed circuit board control system. The lowvoltage output from the low voltage terminal strip is AC voltageto the wall thermostat. R is A/C voltage output to the wall stat.The 24 volt low voltage terminal strip is set up so R-Genergizes the fan, R-Y1 energizes the compressor forcooling operation, R-W1 energizes the compressor andreversing valve for heating operation. The reversing valveis energized in the heating mode. The circuit board hasa fan interlock circuit to energize the fan whenever thecompressor is on if the thermostat logic fails to do so.The output to the wall stat is AC current. Terminal (R) onthe wall stat can be connected to terminal (R) on the PCboard for AC voltage.R = AC current R to G = fan onlyR to Y1 = cooling R to W1 = heatThe MicroTech III unit controller has a lockout circuit tostop compressor operation if any one of its safety switchesopens (high pressure switch and low pressure switch. Ifcompressor low suction temperature is detected, the unitwill go into the cooling mode for 60 seconds to defrostany slush in the water-to-refrigerant heat exchanger. Ifthe condensate sensor detects a filled drain pan, thecompressor operation will be suspended only in thecooling mode. The unit is reset by opening and closingthe disconnect switch on the main power supply to theunit in the event the unit compressor operation has beensuspended due to low temperature (freezestat) switch, highpressure switch, or low pressure switch. The unit does nothave to be reset on a condensate overflow detection.The MicroTech III unit controller fault output sends asignal to an LED on a wall thermostat. Table 7 on page18 lists the faults that cause the Alarm “A” terminaloutput to indicate an alarm condition exists.Remote Reset of Automatic LockoutsThe Remote Reset feature provides the means toremotely reset some lockouts.There are (3) means to reset an automatic lockoutcondition:1 Using the thermostat create 2 demands for capacitywithin 30 seconds2 Press the room sensor or thermostat timed override/reset button for more than 10 seconds3 Turn the unit power offWhen the cause of the fault condition has been cleared,and the unit transitions from not requiring any capacityto needing any capacity twice within 30 seconds(accomplished by user manipulation of the Heat/Cool/Auto/Off switch on the thermostat), an alarm resetequivalent to a tenant override button reset is generated.The intelligent reset counter and the 24 hour timer arecleared when this type of alarm reset is generated.Note: This feature only applies to thermostat controlledsystems.For room sensor controlled units, pressing the “Override”or “Reset” button for more than 10 seconds will apply aground signal to the tenant override in (screw terminalconnection at TB1 pin 4) will clear the lockout alarm oncethe cause of the fault condition has been cleared.A unit power cycle can also be used to clear an automaticlockout if the conditions causing the fault have beencleared.The Intelligent Alarm Reset feature helps to minimizenuisance trips of automatic reset lockouts caused by lowtemperature faults. This feature clears faults the first twotimes they occur within a 24-hour period and triggers anautomatic lockout on the 3rd fault. The retry count is resetto zero every 24 hours.The MicroTech III unit controller has built-in night setbackoperation. A “grounded’ signal to the “U” terminal on TB3of the unit control puts the unit into the unoccupied modefor night setback operation. Fan operation terminatesand unit control will only respond to signal at the W2terminal. Daytime heating and cooling operation islocked out. +24VAC to W2 energizes the compressorand reversing valve for heating operation. Night setbackoperation can be overridden for two hours by energizingthe O on the TB2 terminal of the unit control for 4 to10 seconds. Day thermostat setpoints then control theheating and cooling operation. The MicroTech III unitcontroller also accommodates shutdown operationon receipt of a “grounded” signal to the “E” input,respectively, on TB3 input terminal of the unit control.