Goodman Furnace: Check duct static pressure
Check duct static pressure on a Goodman furnace: Adds the return and supply static readings to get total external static pressure, then compares it with the blower tables.
Applies to: Gas furnaces ACVC96/AMVC96/GCVC96/GMVC96
Common causes of check duct static pressure
- Too much static can cause insufficient airflow, high temperature rise and limit tripping.
- Too little static can overload the motor.
- Closed dampers or registers, and undersized or poorly laid out ductwork, are common causes.
How to fix check duct static pressure: step by step
- With clean filters installed, use a draft gauge (inclined manometer) to measure return static at the furnace inlet. This is a negative reading.
- Measure supply duct static. This is a positive reading.
- Add the two readings together for total external static pressure. Include any coil or electronic air cleaner in the total.
- Compare the total with the allowable minimum and maximum in the blower tables.
- If the total is outside the limits, check for closed dampers or registers and for ductwork problems.
Safety: Gas, electrical and refrigerant work must be done by a licensed technician. Turn off power and gas before servicing, never bypass a safety control, and always follow the manufacturer's manual for your exact model.
If the unit shows an error code, look it up: Goodman Furnace codes
Source: Goodman GMVC96 service and troubleshooting manual, p. 46-47. Written in our own words as a summary; always check the original manual.
General guidance for qualified technicians. The manufacturer's installation and service manual and local codes always take priority. Aurora Star Tech is not affiliated with, endorsed by or sponsored by any equipment manufacturer; brand and model names are used only to identify equipment and belong to their owners.