York DM036 Installation Manual

Also see for DM 036: Technical guide

Contents

York DM036 Installation Manual Manual pdf 45 page image

5011492-XIM-B-0815Johnson Controls Unitary Products 45a. 24 volts at the thermostat Y1 terminalb. Proper wiring between the room thermostat and theUCB, i.e. Y1 to Y1, Y2 to Y2c. Loose wiring from the room thermostat to the UCB.8. If 24 volts is present at the UCB Y1 terminal, thecompressor may be out due to an open high-pressureswitch, low-pressure switch, or freezestat. Check for 24volts at the HPS1, LPS1, and FS1 terminals of the UCB. Ifa switch has opened, there should be a voltage potentialbetween the UCB terminals, e.g. if LPS1 has opened, therewill be a 24-volt potential between the LPS1 terminals.9. If 24 volts is present at the UCB Y1 terminal and none ofthe protection switches have opened, the UCB may havelocked out the compressor for repeat trips. The UCBshould be flashing an alarm code. If not, press and releasethe ALARMS button on the UCB. The UCB will flash thelast five alarms on the LED. If the compressor is lockedout, cancel any call for cooling. This will reset anycompressor lock outs.NOTE: While the above step will reset any lockouts, thecompressor may be held off for the ASCD. See the nextstep.10. If 24 volts is present at the UCB Y1 terminal and none ofthe switches are open and the compressor is not lockedout, the UCB may have the compressor in an ASCD.Check the LED for an indication of an ASCD cycle. TheASCD should time out within 5 minutes. Press and releasethe TEST button to reset all ASCDs.11. If 24 volts is present at the UCB Y1 terminal and thecompressor is not out due to a protective switch trip, repeattrip lock out, or ASCD, the economizer terminals of theUCB may be improperly wired. Check for 24 volts at the Y1“OUT” terminal of the UCB. If 24 volts is present, trace thewiring from Y1 “OUT” for incorrect wiring. If 24 volts is notpresent at the Y1 “OUT” terminal, the UCB must bereplaced.12. For units without economizers: If 24 volts is present at theY1 OUT terminal, check for 24 volts at the Y1 “ECON”terminal. If 24 volts is not present, check for loose wiringfrom the Y1 “OUT” terminal to the Mate-N-Lock plug, thejumper in the Mate-N-Lock plug, and in the wiring from theMate-N-Lock plug to the Y1 “ECON” terminal.13. For units with economizers: If 24 volts is present at the Y1“OUT” terminal, check for 24 volts at the Y1 “ECON”terminal. If 24 volts is not present, check for loose wiringfrom the Y1 “OUT” terminal to the Mate-N-Lock plug, apoor connection between the UCB and economizer Mate-N-Lock plugs, loose wiring from the Mate-N-Lock plug tothe economizer, back to the Mate-N-Lock plug, and fromthe Mate-N-Lock plug to the Y1 “ECON” terminal. If nothingis found, the economizer DME may have faulted and isfailing to return the 24-volt “call” to the Y1 “ECON” terminaleven though the economizer is not providing free cooling.To test, disconnect the Mate-N-Locks and jumper betweenthe WHITE and YELLOW wires of the UCB’s Mate-N-Lockplug. If the compressor energizes, there is a fault in theeconomizer wiring or DME.14. The UCB can be programmed to lock out compressoroperation during free cooling and in low ambientconditions. These options are not enabled by default. Localdistributors can test the UCB for this programming.For units with factory installed economizers, the UCB isprogrammed to lock out compressor operation when theLAS set point is reached.For units without factory installed or with field installedeconomizers, the UCB allows compressor operation all thetime. This programming can be checked or changed by thelocal distributor.15. If none of the above corrected the error, test the integrity ofthe UCB. Disconnect the C1 terminal wire and jumper it tothe Y1 terminal. DO NOT jump the Y1 to C1 terminals. Ifthe compressor engages, the UCB has faulted.16. If none of the above correct the error, replace the UCB.GAS HEAT TROUBLESHOOTING GUIDETroubleshooting of components may requireopening the electrical control box with the powerconnected to the unit. Use extreme care whenworking with live circuits! Check the unit name-plate for the correct line voltage and set the volt-meter 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.