# Harman ESP Test



## gfreek (Mar 2, 2013)

Is there a way to check the ESP besides replacing it??  I assume it works on resistance. What happens if you jump the plug terminals??  Such as on P38+, 2 knob board..


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## lbcynya (Mar 2, 2013)

A perfectly new red wire esp reads about 1.1 k ohm (at about 70 F).  This will change with temperature since that's what it does...  I would guess a bad one would show open....  That's where my experience stops...


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## gfreek (Mar 2, 2013)

lbcynya said:


> A perfectly new red wire esp reads about 1.1 k ohm (at about 70 F). This will change with temperature since that's what it does... I would guess a bad one would show open..


 Thats a start..thanks


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## kinsmanstoves (Mar 2, 2013)

A Harman DDM.


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## gfreek (Mar 2, 2013)

kinsmanstoves said:


> A Harman DDM.


 
Will that work on a 2 knob board with no DDM plug??  Can you check the ESP by itself or will it plug into the back of the board and act like an ESP ???


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## dhall28 (Mar 2, 2013)

yes with an electrical multimeter you can test all the harman temp probes. red ones are as lbcynya said, between 1,000 to 1,100 ohms of resistance depending on what your room temp is (remember if the stove has been off for a while the probe may be much colder from the cold air outside coming through the pipe, i typically take them out to test them between 67-72 degrees) 
All other ESP probes that are NOT red should read around 650,000 to 550,000 ohms resistance, and lastly the room sensing probe should be around 3,600 to 3,300 ohms resistance.
 After taking a good initial read you can breath on them or use any heat source and the resistance should lower as the probe heats up *except* the red which should rise, hope this helps.


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## iceguy4 (Mar 3, 2013)

dhall28 said:


> yes with an electrical multimeter you can test all the harman temp probes. red ones are as lbcynya said, between 1,000 to 1,100 ohms of resistance depending on what your room temp is (remember if the stove has been off for a while the probe may be much colder from the cold air outside coming through the pipe, i typically take them out to test them between 67-72 degrees)
> All other ESP probes that are NOT red should read around 650,000 to 550,000 ohms resistance, and lastly the room sensing probe should be around 3,600 to 3,300 ohms resistance.
> After taking a good initial read you can breath on them or use any heat source and the resistance should lower as the probe heats up *except* the red which should rise, hope this helps.


 


> red ones??


 is the probe red or the wires...mine has a red and black wire
thanks in advance


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## Lousyweather (Mar 3, 2013)

gfreek said:


> Will that work on a 2 knob board with no DDM plug?? Can you check the ESP by itself or will it plug into the back of the board and act like an ESP ???


 
depends on the P38....3 knob board, you can plug the DDM into......2 knob board (old TURBO boards)....cant plug the DDM into, so, no


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## Lousyweather (Mar 3, 2013)

dhall28 said:


> yes with an electrical multimeter you can test all the harman temp probes. red ones are as lbcynya said, between 1,000 to 1,100 ohms of resistance depending on what your room temp is (remember if the stove has been off for a while the probe may be much colder from the cold air outside coming through the pipe, i typically take them out to test them between 67-72 degrees)
> All other ESP probes that are NOT red should read around 650,000 to 550,000 ohms resistance, and lastly the room sensing probe should be around 3,600 to 3,300 ohms resistance.
> After taking a good initial read you can breath on them or use any heat source and the resistance should lower as the probe heats up *except* the red which should rise, hope this helps.


 

this is a good example as to why the dip switches on the newer boards need to be checked and set correctly if replacing the ESP. The red wire probe will work in all boards, EXCEPT the old P38 2 knob boards, where it will fail famously. If replacing a black wire with a red wire probe in any of the other harman units, be mindful of dip switch setting number 5...needs to be ON for a red wire, and OFF for a black wire ESP probe..


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## iceguy4 (Mar 3, 2013)

Lousyweather said:


> depends on the P38....3 knob board, you can plug the DDM into......2 knob board (old TURBO boards)....cant plug the DDM into, so, no


 


whats a DDM??? If its for testing a Harman stove  where can I buy it and how much $$$


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## Lousyweather (Mar 3, 2013)

iceguy4 said:


> whats a DDM??? If its for testing a Harman stove where can I buy it and how much $$$


 Digital Diagnostic Module........your friendly dashing Harman dealer can probably sell you one, part number 3-40-05401, several hundred bucks or so....


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## wil lanfear (Mar 3, 2013)

iceguy4 said:


> whats a DDM??? If its for testing a Harman stove where can I buy it and how much $$$


 Last year I was quoted around $350.00 but I decided I really didn't need one because I have a multi-meter and I know how to use it to troubleshoot.


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## Lousyweather (Mar 3, 2013)

wil lanfear said:


> Last year I was quoted around $350.00 but I decided I really didn't need one because I have a multi-meter and I know how to use it to troubleshoot.


 
agreed- most users wouldnt need one. They are nice for a tech as it allows us to somewhat check things without having to yank parts off and wires apart. For instance, often a bad ESP will read 532 degrees, even on a cold stove...the DDM tells us this, and within 10 seconds, without taking anything apart.....nice.


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## iceguy4 (Mar 3, 2013)

wil lanfear said:


> Last year I was quoted around $350.00 but I decided I really didn't need one because I have a multi-meter and I know how to use it to troubleshoot.


 


Will
will this DDM help with problems like...two days ago my new boiler spit about 2 cups into the ash pan. I was half awake around 4 AM and the stove sounded like it was feeding constantly (unusal sound as my feedrate knob is at 3.5)  I didn't pay much pay it much attention as I was 1/2 asleep.  next morning when I filled it I noticed all the pellets in tha ashpan.   this is the secound time I have found pellets in my ashpan. the last time I was woken up by fire alarm and smoke in basement.  boiler was burning by the time I got down there.  My dealer is saying "wait and see...."   thoughts


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## Lousyweather (Mar 3, 2013)

yea....methinks it'd be a waste of $350 or so......check yo ESP probe for cleaning


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## iceguy4 (Mar 3, 2013)

Lousyweather said:


> yea....methinks it'd be a waste of $350 or so......check yo ESP probe for cleaning


 


Myybe my ESP is fussy.  I kept getting 3 blink codes inspite of cleaning it. I did my first verticle vent pipe cleaning and was supprized how dirty it was. now every weekend I clean all vent pipe with a dryer vent brush and no more code 3 blinks....now its this "anomaly"


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## Lousyweather (Mar 3, 2013)

anomalous, erratic stove issues are VERY tough to figure, as when the tech gets out there "well, it isnt doing it now..."


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## dhall28 (Mar 3, 2013)

iceguy4 said:


> is the probe red or the wires...mine has a red and black wire
> thanks in advance


 
This is the red ESP, everything else besides this red esp is the old thermistor style ESP which has the higher resistance when checked with multimeter


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## gfreek (Mar 3, 2013)

Lousyweather said:


> If replacing a black wire with a red wire probe in any of the other harman units, be mindful of dip switch setting number 5...needs to be ON for a red wire, and OFF for a black wire ESP probe..


 So the red wire will work on 2 knob board if you change dip switch setting, correct??  Just for the heck of it I have the black wire ESP, 2 knob board.. Thinking of getting spare..


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## dhall28 (Mar 3, 2013)

gfreek said:


> So the red wire will work on 2 knob board if you change dip switch setting, correct?? Just for the heck of it I have the black wire ESP, 2 knob board.. Thinking of getting spare..


 
unfortunately I believe you can't,  the red esp's (a K type thermocouple) is only compatible with some of the newer control boards than what you have, if you want specifics i can give you control board part numbers that are compatible with the red esp's monday but I'm almost certain the older two knob boards can't use the red esp


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## Lousyweather (Mar 4, 2013)

nope- you cant use the red probe on the old-style 2 knob P38 board


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## fedtime (Mar 4, 2013)

I had the same issue with my Accentra insert over the weekend - 3 flashes, but I also had a very slow-to-start distribution fan. 

So I cleaned the ESP and the whole stove really well, then pulled the distribution fan and cleaned it from top to bottom.  So far, the problem has not cropped up again, but I fear my ESP is bad - hence the iffy performance of the distribution fan.

Any thoughts on my analysis?


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## dhall28 (Mar 4, 2013)

fedtime said:


> I had the same issue with my Accentra insert over the weekend - 3 flashes, but I also had a very slow-to-start distribution fan.
> 
> So I cleaned the ESP and the whole stove really well, then pulled the distribution fan and cleaned it from top to bottom. So far, the problem has not cropped up again, but I fear my ESP is bad - hence the iffy performance of the distribution fan.
> 
> Any thoughts on my analysis?


 
most likely not a bad esp, just a dirty one that probably had ash surrounding it, the control board decides when to turn on and off the dist. blower and vary the speed based on esp temps. If the blower came on much sooner and no more 3 blink status at any time while operating the stove after the cleaning and you don't notice it again until the stove is due for another cleaning it is unlikely your esp is intermittently going bad but just not getting good hot exhaust gasses flowing over it.


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