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TRI-COLOR (DSI LED) DIAGNOSTIC TABLE
No. of Red BLINKS
1 Flame sensed when no flame should be present
Verify the gas valve is operating and shutting down properly. Flame in burner assemble should extinguish promptly at the end of the cycle. Check orifices and gas pressure.
3 BLINKS 1st-stage pressure switch stuck open/inducer error
Check pressure switch function and tubing. Verify inducer is turning on the pulling sufficient vacuum to engage switch.
4 BLINKS Open limit switch Verify continuity through rollout switch circuit.
5 BLINKS Open rollout/open fuse detect Verify continuity through rollout switch circuit, check fuse.
6 BLINKS 1st-stage pressure switch cycle lockout If the first stage pressure switch cycles 5 times (open, closed) during one call for heat from the thermostat the control will lockout.Check pressure switch for fluttering, inconsistent closure or poor vacuum pressure.
7 BLINKS External lockout (retries exceeded) Failure to sense flame is often caused by carbon deposits on the
flame sensor, a disconnected or shorted flame sensor lead or a
poorly grounded furnace. Carbon deposits can be cleaned with
emery cloth. Verify sensor is not contacting the burner and is locatedin a good position to sense flame. Check sensor lead for shortingand verify furnace is grounded properly.
8 BLINKS External lockout (ignition recycles
exceeded where flame is established and then lost)Check items for exceeded retries listed above and verify valve is not dropping out allowing flame to be established and then lost.
9 BLINKS Grounding or Reversed polarity Verify the control and furnace are properly grounded. Check and reverse polarity (primary) if incorrect.
10 BLINKS Module gas valve contacts energized
with no call for heat Verify valve is not receiving voltage from a short. If a valve wiring is correct and condition persists, replace module.
11 BLINKS Limit switch open - possible blower
failure overheating limit Possible blower failure, restricted air flow through appliance or duct work. Verify continuity through limit switch circuit and correct overheating cause.
12 BLINKS Module Ignitor contact failure Fault code indicates the module ignitor contacts are not functioning
properly. Replace module.Solid Module - internal fault condition Module contacts for gas valve not operating or processor fault.
Reset control. if condition persists replace module.
3 double 2nd-stage Pressure Switch Stuck Open/Inducer Error
Check pressure switch function and tubing. Verify inducer.
1. Obstructions or restrictions
in appliance air intake or flue
outlet are preventing proper
2. Moisture or debris in tubing that
connects pressure switch and
3. Airflow switch jumpered or
f this is a metal vent 80% furnace,Turn Furnace off and remove the vent that connects to furnace and see if it is plugged.
If this is a High Eff furnace witrh pvc vents for exhaust and intake air make sure they are not plugged on the outside.
Turn thermostat all the way up,turn furnace off and wait a few minutes.This should reset any control board fualt.
Turn the furnace back on, if you have a glow coil ignitor it should glow red and then the burners should ignite. If this doesnt happen then:
On High Eff Furnace if the glow coil does not glow red, remove the combustion door to the burners, turn furnace back on, if the glow coil glows and burner ignites, you have an obstruction in the intake air side. If it still does nothing then:
Use caution and remove the exhaust vent from furnace, start furnace, if furnace runs then you have a problem with the vent system
i take it the flash code 3 blinks refers you to the pressure switch...see the schematic. If this is what you are saying than lets move on... the voltage across the pressure switch should read 0 if the furnace is running and calling for heat. you dont need to check each wire to ground but across the two quick connect tabs. you will either read 0 or 24 volts (or there about). if you read 0 the switch is closed and functioning as designed. if it reads 24 volts it is open and there is not enough negitive pressure to close it. this can be due to a leak in the rubber tubing or a clog in the pressure switch, tubing, or induced fan housing connection nipple. the flue pipe may also be clogged or an improper cap is used at the termination. last is the wiring could be faulty going to and from the pressure switch. Hardly ever have we found a broken or faulty switch but it could happen. trust the board in most cases.
Your induce fan motor senor is out. The little fan motor that take out the heat has a sensor that tells the furnace thats its working. Some time it get stuck. Try blowing and sucking into the tube. you should hear a click
ok this is going to sound funny but it seems as though the polarity is reversed going into your furnance. to correct this proiblem you first need to unplug the unit and where the cord goes into the furnance at that connection disconnect the two wires. Once theses are disconnected switch the wires .All you are doing is reversing the way the electricity flows into the circut board. I would wager that is the problem
check the pressue switch and make sure that nothing is in the fan that would cause it to not draw. I have seen water inside of them at times due to the high efficentcy of the units. let me know if this does not solve it please.