Heating, Air Conditioning, Fridge, HVAC/Burner won't light


I have a older freedom 80 furnace made by american standard. Model ADD040C924E0.Lately it sometimes will not start when there is a call for heat. If I go down and shut power off for a few minutes then back on it will start up and run as normal. I am getting 4 blinking lights on the board for a limit switch. I have checked continuity of the switches I can identify and they are all closed. What should I be looking at to figure this out? Thanks


The Freedom 80 is just a model series that includes a lot of different furnaces. Most boards 4 flashes means that there is an "open" limit circuit.

Here is what is probably the error code list for your furnace:

Flashing Slow --- Normal - No call for Heat
Flashing Fast --- Normal - Call for Heat
Continuous ON --- Replace IFC
Continuous OFF --- Check Power
2 Flashes --- System Lockout (Retries or Recycles exceeded)
3 Flashes ---
Draft Pressure Error - Possible problems:
a) Venting problem
b) Pressure switch problem
c) Inducer problem
4 Flashes --- Open Temperature Limit Circuit
5 Flashes --- Flame sensed when no flame should be present
6 Flashes --- 115 volt AC power reversed, poor grounding or system voltage too low
7 Flashes --- Gas valve circuit error
8 Flashes --- Low flame sense signal
9 Flashes ---
Check Ignitor Circuit and Line "N" to 24VAC "Common" voltage (≤ 2 volts)
[possible grounding problem]

Most of the time limit problems are related to poor air flow, so a dirty filter is a legitimate cause for this. Other causes could be a dirty indoor air conditioning coil, too many closed air registers, air registers or returns blocked by furniture or drapes, a blower speed that is too low, duct problems, or dampers that are not positioned properly. Check all these things to make sure they are not hurting your airflow.

If one of the rollout switches is tripped it could be caused by a partially blocked flue pipe  

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40+ years diversified experience.An HVAC/Refrigeration Self Employed Contractor since 1986. NATE Certifield. Answer questions pertaining to Residential and Commercial Air Conditioning , Warm Air Heating, Heat Pump systems.Mechanical and Electrical troubleshooting of these systems.Be as detailed as possible when describing problem.Packaged unit or split systems.No appliance questions.


Installation and Troubleshooting, Mechanical and Electrical, in following areas, Refrigeration ( Walk In and Reach In Coolers and Freezers ) Commercial Roof Top and Packaged Heating/Cooling ( Natural Gas,Propane, Electric, and Heat Pumps ) Computer Room Air Conditoning Systems,Commercial Residential Packaged and Split Systems Air Conditoning and Heat Pumps.Warm Air Oil , Natural and Propane Gas Heating systems.

Graduated from Private Technical School in 1975. An HVAC/Refrigeration Contractor . Have Unlimited Heating/Piping and Cooling Contractor License.Limited Sheetmetal Contractors License.NATE Certifield. York Certifield Master Heat Pump Technician 1986. Served 33 years combination Active Duty Air Force , Air Force Reserves and Air National Guard in the HVAC/Refrigeration Shop/Mechanical Shop. Troubleshooting/Installing HVAC/Refrigeration Equiptment Worldwide. Retiring in 2003 as a Senior NCO ,and a Mechanical Superintendent.

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