Honeywell S9200 Furnace Control Codes: Red and Amber LEDs

By Ray Bennett · Updated 2 October 2026 · 6 min read · Checked against the maker’s manual

Honeywell S9200 Furnace Control Codes: Red and Amber LEDs

Short answer

The Honeywell S9200 is a universal replacement furnace board with three lights. The red one carries the codes: 2, 3 and 4 are the pressure switch, 5 an open limit, 6 unexpected flame, 2 + 1 a soft lockout after failed ignition tries, 3 + 2 a blown fuse and 4 + 1 a rollout lockout that needs the power cycled. The amber light shows the flame.

The Honeywell S9200U1000 is a universal hot surface ignition control, a replacement board fitted to furnaces of many brands. It has three lights. The red one carries the status and error codes, the amber one shows the flame, and the green one only matters with a communicating thermostat.

Everything on this page comes from the S9200U1000 installation instructions, 69-2075EF-09, published by Resideo, which makes Honeywell Home controls. Resideo itself says its codes are a general guide, and to follow the furnace maker’s service instructions when they are available.

Before you start

What to carry: a torch and a pen. Ten minutes.

Gas or electric? A gas furnace control, for natural gas or propane.

How to count. Resideo says a single code flashes a number of times, then stays off for three seconds. A pair such as 2 + 1 flashes the first number, stays off for one second, flashes the second number, then pauses three seconds.

A fast blink at start-up is normal. Resideo says the red light blinks fast for about two seconds at power-up. If it keeps blinking fast, around eight times a second, the control has failed.

Three codes where you stop. 6 on the red light. Resideo says the control is still seeing flame after the 20 second delay, when it should be out, and to check for gas valve leakage. Turn the gas off and call a technician.

4 + 1, the rollout circuit. A hard lockout. Resideo says to check the flue and heat exchanger for restrictions and the burner, and not to operate the furnace until the repairs are made: what a rollout switch is telling you.

4 + 2, the gas valve relay. Resideo says the gas valve relay was found welded five times. Only a power cycle resets it, and a repeat means a new control.

The three lights

Amber for the flame, red for the status and the codes, green for communication with a communicating thermostat.

Check 1Free, two minutes

Read the right light

Amber, off. Powered, with no flame. Normal.

Amber, heartbeat. A call for heat with flame present. Normal.

Amber, periodic blink. Resideo says the flame current is low, and to check the flame rod for contamination or loose wiring, and the gas pressure.

Red, pulse. A short flash every four seconds: powered, standby, no call for heat.

Red, heartbeat. A call for heat, normal operation.

Green. Bus activity. Resideo notes it is active even with an ordinary thermostat, and it tells you nothing about the burner.

Every code on the red light

A pulse is standby and a heartbeat is a normal call for heat. A single count or a pair is a code.

Code	What Resideo says it means	What Resideo says to check
2	Pressure switch failed open	Inducer, switch wiring, hose loose or holding water, blocked vent, low voltage
3	Pressure switch failed closed	Shorted wiring, switch contacts, water or blockage in the hoses
4	Pressure switch opened during ignition or running	Restricted vent, low voltage, water in a horizontal vent
5	Limit switch open	Clogged filters, restricted airflow, slow blower speed
6	Unexpected flame after the 20 second delay	Gas valve leakage
2 + 1	Soft lockout, too many ignition retries	Gas supply and valves, igniter, flame rod, low voltage
2 + 3	Soft lockout, last retry from the pressure switch	Switch wiring, slow inducer, venting, unstable voltage
2 + 4	Soft lockout, last recycle from flame failure	Gas supply, flame sensor wiring
2 + 5	Soft lockout, limit open or open over 3 minutes	Filters, airflow, blower speed
2 + 6	Soft lockout, gas valve failed to open	Gas valve and its wiring
3 + 1	Low 24 volts	The transformer and the low voltage circuit
3 + 2	Bad fuse	A short to the chassis, then a fuse of the same type
3 + 4	Gas valve miswired or relay welded	Gas valve wiring
3 + 5	Control failed its self check	Cycle power; replace the control if it repeats
3 + 6	Reversed line polarity or poor earth ground	Line wiring and the ground
4 + 1	Hard lockout, rollout circuit open	Flue, heat exchanger, burner, rollout switch
4 + 2	Hard lockout, gas valve relay welded five times	Gas valve wiring, then the control

The checks that are yours

Check 2

Work the free checks

5 and 2 + 5: airflow. Resideo names clogged filters and restricted airflow, and says to remove the restrictions and open more ducts. Change the filter and open every register: why a furnace overheats and cuts out.

2, 4 and 2 + 3: the vent and the hoses. Look at the vent outside for a blockage, and at the pressure switch hose for water or a split: the places a pressure switch fault hides.

2 + 1 and 2 + 4: the gas. Resideo’s first check is the gas supply and the shut-off valves. Make sure the gas is on at the furnace, and on propane that the tank has gas.

Amber blinking: the flame rod. Low flame current usually means a contaminated rod: how to clean a flame sensor safely.

3 + 2: the fuse. Resideo says to look for a short first, then turn off the power and replace the fuse with one of the same type. If the fuse blows again, the fault is still there.

Resetting a lockout

Check 3Free, five minutes

Know which lockout you have

Soft lockout, the 2 + codes. Resideo gives three ways out: remove the power for longer than 10 seconds, remove the call for heat for longer than 5 seconds but less than 20, or wait for the automatic restart. Resideo says a soft lockout resets itself after one hour.

Hard lockout, 4 + 1 and 4 + 2. Resideo says only cycling the power resets it. Do that only after the cause is found.

Stored codes. Resideo says the control keeps the ten most recent error codes, which a technician can recall with a jumper on the thermostat terminals.

When it needs a technician

Check 4

Know when to stop

6, 3 + 4 and 4 + 2. Gas valve leakage, a miswired gas valve or a welded relay. Gas and control work.

3 + 6. Reversed polarity or a poor earth ground. An electrician’s job.

3 + 5, or a fast blink that never stops. Resideo says the control has failed its self check or its hardware, and cannot be repaired, so it is replaced.

3 + 1. Low 24 volts, which Resideo traces to the transformer and the low voltage loads.

Questions people ask

What does 2 + 1 mean on a Honeywell S9200?

A soft lockout after too many ignition retries. Resideo points at the gas supply, the igniter and the flame rod. It resets itself after an hour, or with a short thermostat or power reset.

What does 5 flashes mean?

The limit switch is open. Resideo names clogged filters, restricted airflow and a slow blower speed. Start with the filter and the registers.

What does 3 + 2 mean?

A bad fuse. Resideo says to check for a short, such as a limit, rollout or pressure switch wire touching the chassis, then replace the fuse with the same type.

What does 4 + 1 mean?

A hard lockout from the rollout circuit. Resideo says to check the flue, the heat exchanger and the burner before running it, and only a power cycle resets it.

Why is the amber light blinking?

Low flame current during a call for heat. Resideo says to check the flame rod for contamination or loose wiring, and the gas pressure.

Why does the red light flash every few seconds?

That short pulse is standby. The control is powered and waiting for a call for heat.

Sources: Resideo (Honeywell Home) installation instructions 69-2075EF-09 for the S9200U1000 universal hot surface ignition integrated furnace control