Harman Digital Control Board Troubleshooting Tips

What causes this error

A two blink status light error signifies that the stove’s pressure switch has failed to close the electrical contacts of the switch or that the contacts were closed and an event caused the contacts to open.

The feeder motor has an electrical circuit that runs through a pressure switch. This switch MUST detect a drop in air pressure within the stove to enable the feed motor to have power. It is very rare that the switch itself will fail and should only be considered for replacement after all troubleshooting efforts have been attempted.

How it can be fixed

• The most common solution to get rid of a 2 blink error code is cleaning the stove and venting. Ash obstructions within either the stove or venting will cause back pressure within the stove, thus keeping the switch itself from completing the feed motor circuit. Verify that the stove and venting are clean and clear of obstructions and restart the stove.
• If the problem persists, verify that the combustion blower is actually powered up and spinning. If the combustion blower isn’t turning on or spinning, no air will be flowing through the stove and the air flow switch will not close. If you recently performed a cleaning or service (or had a cleaning or service performed by a service technician) and the #2 error presented itself AFTER the service, there is a good chance that something wasn’t put back together properly or something was damaged. Here is a list of things to check.
• If your stove is an insert and the venting was not cleaned properly while the stove was pulled out, there’s a good chance that ash fell down and is blocking the combustion blower from spinning.
• If your stove has a combustion motor cover inside the stove, make sure it was put back and secure.
• Accentra Insert & XXV: These stoves combustion blower is removable, make sure the blower is properly secured and tight fitting. It is possible on these two stoves improperly install the blower.
• If service was performed on the combustion blower itself, make sure the impeller blades aren’t rubbing against the cover or the cooling fan blades aren’t rubbing on their cover or a pellet isn’t obstructing the cooling fan from turning.
• If wires were disconnected, make sure the combustion blower is plugged in to the correct wires.
• If the combustion blower is NOT turning and everything is wired correctly and nothing is obstructing it from turning… AND the Combustion Blower lights are illuminated on the control board, a new combustion blower will need to be installed. You may also install a pressure switch at the same time to rule out all errors.

What causes this error

A three blink error code means that the control board has not detected the ESP (Exhaust Sensing Probe) at startup that it lost communication with it while the unit was running.

How it can be fixed

What causes this error

Four blink status lights errors are caused by a failure to maintain an electrical circuit through the room sensing probe. If the probe is not connected to the stove, if a crimped wire connection on the room sensing probe is faulty, or if the sensing probe wire or resistor at the end of the wire is damaged, the stove will immediately display the 4 blink error code when the stove is attempted to be used on “Room Temp” mode. If you get this error code please note that you can still use the stove on the “Stove Temp” or “Constant Burn” mode, however; the stove will not turn off and on or modulate up or down as the desired room temperature is reached.

How it can be fixed

• If the room sensing probe is plugged in and you get this error, replace the room sensing probe.
• Accentra Inserts & P35i (Excluding the Accentra 52i): require you to cut the ¼” factory crimped wire connections from the ESP probe and install 1/8” connections supplied in the installation kit. It’s very common for installers to use pliers to make these crimped connections instead of actual crimpers and sometimes the wires will slip out of the connections if the proper tools weren’t used. If this is the case, simply install new connectors.
• All Harman Pellet Stoves are designed to monitor the room temperature in the “Room Temp” mode using this room sensing probe, however; it is possible to connect a simple heat only wall thermostat to the stove using the room sensing probe connections, with the probe itself being wired in series with the thermostat. This is a “customized” approach that isn’t really supported by Harman but was at one time. Harman stoves that are used in this way will keep the temp dial on the stove turned all the way up to 95 degrees and used the wall thermostat to “clip” the signal or disconnect the sensing probe from the controller. When this happens, the controller will immediately go into a 4 blink error and the stove will shut down. When the thermostat call for heat again, the circuit will be restored and the stove will start up or recover and continue to run normally until the thermostat is satisfied again. We just thought we’d toss that out there in the event that your stove was configured in this way. If it is, and it’s still not working, it’s possible the probe is malfunctioning and as such…the thermostat function will not work either. We’d suggest replacing the room sensor probe at this point.

The status light will blink five times when the stove attempted to start and a 36 minute time limit was reached with no noticeable rise in the exhaust temp as monitored by the ESP. When this error occurs, generally there will be unburned pellets flowing over the burn pot edge and falling into the ash bin.

How it can be fixed

• This error can occur when a stove is very dirty and air flow is diminished or when the ignition heating element (igniter) has shorted out. If you get this error, turn off the stove and restart the startup sequence. Let the stove run for 2 minutes and then open the door, clean the pellets away in the burn pot and fell with your hand whether the downward slope of the burn pot is “warm”.
• If the burn pot is warm, then you know the igniter is heating up. If the igniter is warm, shut down the stove and perform a regular cleaning. Make sure that the air flow path under the burn pot (access through the front of the burn pot by loosening the wingnuts) is free and clear of fines and ash. Scrape the downward slope of your burn pot very well and restart the unit.
• If the burn pot is cold to the touch and the “Igniter” light is illuminated on the control board, there is a very good chance that your igniter has shorted out and will need to be replaced if you want to have automatic starts. A Harman stove with a faulty igniter can always be used manually. To start your stove manually (light the fire yourself), move the igniter toggle switch from auto to manual on the controller and follow your owner’s manual’s instructions for light a fire manually.

What causes this error

A six blink error code is rare and it occurs when the controller registers a series of lower than normal exhaust temperatures over a 25 minute span of time. Your owner’s manual will indicate that this could be caused by a very dirty stove/ vent scenario but it’s not usually the cause. To be fair, cleaning the unit should be considered whenever an error code presents itself. Start there, however; 6 blink error codes most often have to do with too much air entering the burn chamber and overcoming the fire. This causes the fire to collapse and for the expected heat output to drop instead of rise.

How it can be fixed