Harman P38 help..please

[jm1972]

The stove was already installed in the house when I bought it, so I am not sure how old it is. I have been using it for the 5 years I have lived here. Last season we had the circuit board replaced because the stove was not working at all. Now this season, it has developed a new issue. The distribution blower will turn off at random intervals. Sometimes it will run fine for hours, other times it will shut off after a couple minutes. After a bit (anywhere from a couple minutes to an hour), the fan will come back on. The stove will be very hot and it seems like it’s trying to cool itself down before starting the blower. I tried to put it into turbo mode because that will run all of the motors, but it will only feed as if it was on a 2 or 3 feed rate. I looked through the forums for hours last night and could not find anyone that really has the same problem. I have seen mentioned the ESP that could cause problems like this. Can anyone let me know where to find this on/in the stove? I do have the owners manual and cleaning instructions from the Harman website, but not really sure from looking at the picture how to get to this. Can the ESP be disconnected so that the blower will just run?

Thanks for any help.

 

[summit]

ESP probe lets the stove know how hot/ cold it is... It lets the board know when firebox temp is high enough to get outta start up mode and engage the blower. If you disconnect it, the stove won't work at all. It is located in the tailpipe, just before the cast iron flue outlet... you'll see a pair of black or white wires running to the butt end of a silver probe held in by a 1/4" drive sheet metal screw. Remove thescrew, and it slides right out. Yoou can also see it if you remove the ashpan and exhaust fan cover inside the rear of the pedestal and look straight thru the exhaust hole... its about 2" long. I'd try removing it and cleaning it off 1st before you go replacing it.... They make a handy ESP replacement kit with splicers so you don't have to reroute new wires. Also, check the fan... try discnnecting it from the board and plugging it in direct to walll w/ a tester cord ( a cut off extension cord fitted w/ some 20 cent male quick connects works great!)... see if it stayrs running constantly when plugged in direct. sometimes when the motors are about to die, they start to randomly stop working.

 

[jm1972]

When I cleaned the stove this morning, I did see the probe. Looks pretty caked with ash. So you're saying that I don't have to remove the chimney pipe to get it out? I will try this later when the house is warmed up and clean it better. Couple questions: I will test the fan as well, does it matter which wire, black or white, goes to positive and negative on the test cord? Not sure how to tell which is which on an extension cord. Where can I get an ESP kit to replace if the fan tests ok?

Thanks again.

 

[rickwa]

the smaller blade of the outlet is the hot (black) wire

 

[krooser]

Good cleaning video for Harman's... this should be done at least once per year.... and your vent should be cleaned after every ton IMHO, of course.
http://www.youtube.com/watch?v=eBUfkD-GiaE

 

[timjk69]

I found a good way to clean my ESP. I pull it our and use my stove glass cleaner and a piece of gray Scotch Brite. Makes it nice and shiny in a couple of minutes.
I use a small dab of sealer on re installation. Don't get sealer on the probe.