Carrier PG9UAA Troubleshooting Manual

Contents

Carrier PG9UAA Troubleshooting Manual Manual pdf 36 page image

36APPENDIX EQUICK REFERENCE INFORMATIONPG9UAA PRESSURE SWITCH MAKE/BREAK POINTSUNIT SIZE (BTUH) HIGH--HEAT PRESSURE SWITCH LOW--HEAT PRESSURE SWITCHMake Point Break Point Make Point Break Point60,0001.81 in. W.C. max 1.63 in. W.C. +/-- 0.050.86 in. W.C. max 0.71 in. W.C. +/-- 0.0580,000 0.91 in. W.C. max 0.76 in. W.C. +/-- 0.05100,000 0.95 in. W.C. max 0.81 in. W.C. +/-- 0.05120,000 0.86 in. W.C. max 0.71 in. W.C. +/-- 0.05Flame Sensor Microamperage:Microamp Range: 0.5 to 6.0 microampsTypical Reading: 4 to 6 microamps in high heatHot Surface Ignitor Reading:PG9UAA – Ohm reading of HSI @ 70°F: 40 to 70 ohms(resistance will remain relatively stable over the life of the igniter).The Silicon Nitride igniter in this furnace is not voltage sensitive and will work within the voltage range of 102 to 132 VAC. Hence, there isno voltage regulation circuits on the furnace control board. A new Silicon Nitride igniter has a normal resistance range of 40 to 70 ohms atroom temperature and is relatively stable over the life of the igniter. The igniter resistance will increase with temperatures above roomtemperature.Gas Valve Ohm Readings:M to C:Resistance cannot be measured with an ohm meter because there is a bridge rectifier in the gas valve circuit.Hi to C:Resistance cannot be measured with an ohm meter because there is a bridge rectifier in the gas valve circuit.Power Choke (Inductor):Run unit in cooling mode, measure motor amp draw before power choke. Then rerun unit in cooling mode, but this time measure amp drawwithout power choke in line. The amp draw should be higher without power choke. Some ammeters will register a lower amp draw (look fora change in amperage).