York SUNLINE DCG Series Installation Manual

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York SUNLINE DCG Series Installation Manual Manual pdf 50 page image

290699-YIM-B-060750 Unitary Products GroupNOTE: While the above step will reset any lockouts,the compressor may be held off for the ASCD.See the next step.10. If 24 volts is present at the UCB Y1 terminal andnone of the switches are open and the compressoris not locked out, the UCB may have the compres-sor in an ASCD. Check the LED for an indication ofan ASCD cycle. The ASCD should time out within5 minutes. Press and release the TEST button toreset all ASCDs.11. If 24 volts is present at the UCB Y1 terminal and thecompressor is not out due to a protective switch trip,repeat trip lock out, or ASCD, the economizer termi-nals of the UCB may be improperly wired. Check for24 volts at the Y1 “OUT” terminal of the UCB. If 24volts is present, trace the wiring from Y1 “OUT” forincorrect wiring. If 24 volts is not present at the Y1“OUT” terminal, the UCB must be replaced.12. For units without economizers: If 24 volts ispresent at the Y1 OUT terminal, check for 24 voltsat the Y1 “ECON” terminal. If 24 volts is notpresent, check for loose wiring from the Y1 “OUT”terminal to the Mate-N-Lock plug, the jumper in theMate-N-Lock plug, and in the wiring from the Mate-N-Lock plug to the Y1 “ECON” terminal.13. For units with economizers: If 24 volts is present atthe Y1 “OUT” terminal, check for 24 volts at the Y1“ECON” terminal. If 24 volts is not present, checkfor loose wiring from the Y1 “OUT” terminal to theMate-N-Lock plug, a poor connection between theUCB and economizer Mate-N-Lock plugs, loosewiring from the Mate-N-Lock plug to the econo-mizer, back to the Mate-N-Lock plug, and from theMate-N-Lock plug to the Y1 “ECON” terminal. Ifnothing is found, the economizer actuator mayhave faulted and is failing to return the 24-volt “call”to the Y1 “ECON” terminal even though the econo-mizer is not providing free cooling. To test, discon-nect the Mate-N-Locks and jumper between theWHITE and YELLOW wires of the UCB’s Mate-N-Lock plug. If the compressor energizes, there is afault in the economizer wiring or actuator.14. The UCB can be programmed to lock out compres-sor operation during free cooling and in low ambi-ent conditions. These options are not enabled bydefault. Local distributors can test the UCB for thisprogramming.For units with factory installed economizers, theUCB is programmed to lock out compressor opera-tion when the LAS set point is reached.For units without factory installed or with fieldinstalled economizers, the UCB allows compressoroperation all the time. This programming can bechecked or changed by the local distributor.15. If none of the above correct the error, replace theUCB.GAS HEAT TROUBLESHOOTING GUIDEBefore beginning symptomatic troubleshooting activi-ties read the flash code LEDs on the unit control board(UCB) and the ignition control board (ICB). Fault codeshave a quick sequence of flashes indicating the flashcode number followed by a pause with the LED off. TheICB flash codes are repeated until the fault is cleared.The ICB monitors itself, the centrifugal switch, lockoutTroubleshooting of components may requireopening the electrical control box with the powerconnected to the unit. Use extreme care whenworking with live circuits! Check the unitnameplate for the correct line voltage and set thevoltmeter to the correct range before making anyconnections with line terminals.When not necessary, shut off all electric power tothe unit prior to any of the following maintenanceprocedures so as to prevent personal injury.Label all wires prior to disconnection when ser-vicing controls. Wiring errors can cause improperand dangerous operation, which could causeinjury to person and/or damage unit components.Verify proper operation after servicing.The furnace may shut down on a high tempera-ture condition during the procedure. If thisoccurs, the UCB energize the supply air blowermotor until the high temperature limit has reset.Caution should be used at all times as the supplyair blower may energize regardless of the roomthermostat fan switch position.