Harman Black Thermistor Exhaust Sensing Probe (ESP), 3-20-11744-AMP


A $95.00 Savings vs the OEM

SKU 3-20-11744-AMP
MPN 3-20-11744
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Replacement Harman Black Exhaust Sensing Probe (ESP) for select pellet stoves.

A 3 blink error code means that the control board has not detected the ESP (Exhaust Sensing Probe) at startup or that it lost communication with it while the unit was running.

  • Verify that the ESP probe is clean by removing it and looking at it, clean if necessary. It should be a silver-colored metal.
  • If you replace it, make sure you replace it with the proper one for your unit. There are two versions; a probe with black wires and a probe with red wires, replace accordingly.
  • If the probe itself looks “bent” it’s probably broken.
  • Before replacing the probe verify that the probe itself is actually plugged into the controller and the contacts on the controller are “clean”
  • On the front side of each controller, there is a red rectangle box with a series of 8 micro-switches called DIP switches. The controller must be removed from the unit to access them. DIP switches allow multiple stoves to use the same controller but run different programs according to the stove’s required functions. The #5 DIP switch must be set to “OFF’ or down for ESP probes with black wires and set to “ON” for DIP switches with red wires. 3 blink error codes can be caused by installing the improper colored wired ESP with the wrong DIP selection.

Also compatible With Eco Choice BA100

Replacement For Part Number s :
  • 3-20-11744
  • 1-00-00744

UPC #: 652174647279

Compatible Models


  • Accentra Cast Free Standing
  • Accentra Insert (Pre: 008241201)
  • Advance (Pre: 008360001)
  • DVC 500 (Pre: 008065076)
  • Invincible Insert
  • Invincible RS
  • Magnum (44 Mag)
  • P38
  • P38+ (Pre: 008190059)
  • P61 (Pre: 008085055)
  • P61A (Pre: 008085803)
  • P68 (Pre: 008281295)
  • PB105
  • PC45 (Pre: 008055031)
  • Pellet Pro II
  • PF100
  • XXV (Pre: 008200828)



Assembly Instructions For Harman Black Thermistor Exhaust Sensing Probe (ESP), 3-20-11744-AMP

You must be careful not to bend an ESP probe if removing it for maintenance purposes. Bending the sheath of the probe will usually ruin the sensor. Likewise, when cleaning your stove, care should be taken to not bend the sensor when cleaning. Do not send brushes or vacuum tools through the stove blindly. Before cleaning your stove for the first time, find the ESP probe and make sure that it is not going to be in the way when cleaning. If it is, remove it from its mount prior to performing work.

Using a 1/4" socket, remove the mounting screw and remove the thermocouple from the stove. Trace the wires back to the control board and unplug the wires.

DIP Setting by Stove Model


The Control Board/ESP combination is responsible for all high limit safety control. There are 2 high limits, one normal operation high limit and one backup high limit. The control has an automatic diagnostic circuit that continuously monitors the ESP and Room Sensor for faults. If a fault should occur, the control sends a status alert and at the same time the unit goes down to minimum feed/ minimum burn as a safety condition.

Red thermocouples can be use in place of black thermocouples if the #5 DIP switch settings on the control board are set to 'ON', black thermocouples have the #5 DIP switch setting 'OFF', however; red thermocouples are slightly larger in diameter than black ones and often will not fit into the mounting holes of black thermocouples.

Thermocouple wires cannot be cut and spliced.


Unfortunately, sometimes products do not work like they are supposed to. We offer a 90 day warranty on manufacturer defects. Some manufacturers make this a very simple and easy process unfortunately others do not. Items must be used in accordance with the manufacturers guidelines to qualify for warranty replacement. Please be advised that warranty claims for these parts may take up to 4 weeks for processing, and customers must cover shipping.

Shipping Info

This Item Qualifies For Free Shipping With Orders Over $199!

When Will My Order Ship

All orders are typically processed within 24 hours of receiving payment and are shipped from us same day if placed before our shipping cutoff time (Monday - Friday: 1PM, Saturday: 10AM, Sunday: No Shipping), orders placed after our cutoff time are shipped the next morning.

How Does Free Shipping Work?

Most orders over $199 qualify for free shipping! Orders which ship for free are shipped with either USPS or UPS based on our discretion. If you are using a PO box, free shipping orders will always go USPS.

Is Expedited Shipping Available?

We offer both overnight and two day air shipping services for all orders placed within the Continental United States. For information on shipping cut-off times, go to our shipping page.

Do You Ship To Canada?

We ship to Canada! We estimate USPS to take 4-10 days once receiving your package from us. We do not offer expedited shipping of any kind to Canada. Please allow an extra 2-5 days for all shipments to Canada. Free shipping is not available to Canada.

Do You Ship To Alaska Or Hawii?

We ship to both Alaska and Hawaii! We do not offer next day or two day shipping to Alaska or Hawaii. Free shipping is not available to Alaska or Hawaii.

Do You Ship Outside The US Or Canada?

Unfortunately, at this time we do not offer international shipping other than to Canada.

If you wish to calculate shipping for an item which does not qualify for free shipping, or if you would like the cost to expedite your order, please do the following. Add the item you want to order to your cart and click here to be taken to the cart page where you can enter your country, state / province, and zip code for an estimate.

Shipping Time Estimations

For information on shipping time estimations, see either the Shipping Information & Transit Times on the cart page, or go to our shipping page.

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Customer Reviews

Based on 10 reviews
Deborah S.
Super easy to order

Great to deal with

Saved Our Stove

Had a problem with our pellet stove and was unable to find anyone to service it. After a little research I was able to determine the problem, purchase parts, which I received very quickly, and fix the stove myself!! I learned something and was able to save the cost of a service call. Thanks!!

Betzaida C.
Fast service.

Got my part quick and it was the right part. Thanks

Mark K.
Esp prope

Excat fit part fixed my problem

William T.

Great People&Products! THank You!


Ask a Question
  • Will this work for my P61A pellet stove My part number is 3-20-00744

    If the wires coming from the probe are black and/or black with white stripe you can use 3-20-11744(AMP). However, if the wires are red, you will need to use 3-20-00844(AMP).

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