Appendix E - - Quick Reference Information - Carrier PG9UAA Troubleshooting Manual

UNIT SIZE (BTUH)
60,000
80,000
100,000
120,000
Flame Sensor Microamperage:
Microamp Range:
Typical Reading: 4 to 6 microamps in high heat
Hot Surface Ignitor Reading:
PG9UAA – Ohm reading of HSI @ 70°F:
(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 is
no voltage regulation circuits on the furnace control board. A new Silicon Nitride igniter has a normal resistance range of 40 to 70 ohms at
room temperature and is relatively stable over the life of the igniter. The igniter resistance will increase with temperatures above room
temperature.
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 draw
without power choke in line. The amp draw should be higher without power choke. Some ammeters will register a lower amp draw (look for
a change in amperage).
APPENDIX E
QUICK REFERENCE INFORMATION
PG9UAA PRESSURE SWITCH MAKE/BREAK POINTS
HIGH- -HEAT PRESSURE SWITCH
Make Point
1.81 in. W.C. max 1.63 in. W.C. +/- - 0.05
0.5 to 6.0 microamps
40 to 70 ohms
Break Point Make Point
0.86 in. W.C. max
0.91 in. W.C. max
0.95 in. W.C. max
0.86 in. W.C. max
36
LOW- -HEAT PRESSURE SWITCH
Break Point
0.71 in. W.C. +/- - 0.05
0.76 in. W.C. +/- - 0.05
0.81 in. W.C. +/- - 0.05
0.71 in. W.C. +/- - 0.05