York SUNLINE DCG Series Installation Manual

Contents

York SUNLINE DCG Series Installation Manual Manual pdf 51 page image

290699-YIM-B-0607Unitary Products Group 51due to > 16 pilot flame losses, primary limit, rollout anda flame present when the ICB expects no flame.With power applied to the unit, if the LED on the ICB isflashing the heartbeat and the furnace will not operate,then proceed to the symptomatic troubleshooting sec-tion. If the ICB LED is not flashing, then perform the ICBtroubleshooting procedures. If the ICB has a flash codeother than the heartbeat, then determine the flash codeand locate its troubleshooting procedures in the flashcode troubleshooting section. Refer to Table 33 for flashcode identification and component causing fault.FLASH CODE TROUBLESHOOTINGPower to the unit should be interrupted during the trou-bleshooting of individual components unless otherwiseindicated. All troubleshooting procedures assume theunit is wired per the wiring diagram. If there is any indica-tion the unit has been previously repaired, then the firstpriority is to verify that the furnace is wired per the wiringdiagram. Miss-wired units will give false flash codes.IGNITION CONTROL BOARDThe ICB controls the ignition of the pilot, the openingand closing of the gas valves and the operation of thedraft (inducer) motor. It also monitors all the furnacesafety components.If the ICB LED is on steady, then verify the wiring of theunit to the wiring diagram and if ok, then replace theICB. If the unit has power and the ICB LED is not flash-ing, then remove the 3 pin connector from the ICB.Measure the control voltage between terminals 1 and 2of the wiring harness connector. The control voltagemust be between 18 and 30 volts. If control voltage isnot present, then check the 3.2A circuit breaker to ver-ify that the circuit breaker has control voltage on bothinput and output terminals. If control voltage is presenton the input and not the output of the circuit breaker,then reset or replace the circuit breaker as necessary.If control voltage is present on both sides of the circuitbreaker, then check the power and common wiresbetween the unit control box and the ICB and repair asnecessary. If the control voltage is present, then verifythe cleanliness of the harness and the ICB connector,clean if necessary and reconnect the wiring harness tothe ICB and observe ICB LED. If it now flashes theheartbeat, then the fault was a bad connectionbetween the harness connector and the ICB connectoror a broken wire exists in the harness. With the har-ness connected to the ICB, gently move the wires inthe harness while observing the ICB LED. If heartbeatis steady, then verify proper operation of the furnace. Ifthe ICB does not flash the heartbeat, then gently movethe wires in the harness connector while observing theICB LED. If you get any flashes of the ICB LED, thenthere is still a bad connection or a broken wire. If noflashes are seen while gently moving the wires with theharness connected to the ICB, then replace the ICBand verify proper operation of the furnace.CENTRIFUGAL SWITCHThe centrifugal switch is an integral part of the draftmotor. The centrifugal switch closes when the motorspeed increases to ~2500 rpm and opens when themotor speed descends to ~2000 rpm.If a flash code indicates the centrifugal switch is caus-ing a fault, then1. If the flash code indicates the switch is open withthe draft (inducer) motor on (flash code 2), thena. Disconnect power to the unit. Using a screw driver,spin the draft motor blower wheel. If bound or drag-ging, then visually inspect the draft motor blowerwheel area for debris. If debris is present, then cleardebris and verify proper furnace operation. If clear,then replace the draft motor and verify proper fur-nace operation.b. Restore power to unit and induce a call for heat. Mea-sure the voltage across the two draft motor leads(white and red). If it is less than 177 volts, then checkand repair the power circuit to the draft motor. If thevoltage is greater than 176 volts and the draft motor isnot turning, then disconnect power and draft motorpower leads. Measure the resistance of the draftmotor windings. If an open circuit exists in the motor,then replace the draft motor. If the voltage is greaterthan 176 volts and the motor is turning, then checkthe centrifugal switch wiring between the ICB and thedraft motor. If ok, then disconnect power to the unitand place the gas valve in the off position. Prepare totemporarily jumper the wires connected to terminals 3and 8 of the ICB 9 pin harness connector by discon-necting the draft motor leads from the 9 pin harness.Restore the power to the unit and induce a call forheat. Jumper wires 3 and 8. If the ignition sequenceis started after 15 seconds (audible sparking of theigniter), then replace the draft motor reconnecting thecentrifugal switch wiring per the wiring diagram. If not,then replace the ICB, remove the jumper and recon-nect the centrifugal switch wiring per the wiring dia-gram. Place the gas valve in the on position andverify proper furnace operation.2. If the flash code indicates the switch is closed with thedraft (inducer) motor off (flash code 3), then discon-nect the 9 pin connector from the ICB and measurethe continuity of the centrifugal switch with a batterypowered test light or an ohm meter between termi-nals 3 and 8 of the harness connector. If a closed cir-