Harman P38 Feed Rate not quite right

[PeteFromMaine]

So I've used a P38 as my only heat source in a smallish Cape the last 5 years and it's worked great. The only problem I've had with it is when temps get really low (like in the single digits and below 0). It never seems to put out enough heat. I have even set the Feed Rate to 6 for the past 2 years and using Green Supreme Lignetics soft/hard pellet mix and there is always at least 1 inch of ash in the burn pot, it never feeds more pellets than that. It never seems to get a nice high flame as when it first starts up after a cleaning.

It's almost as if the ESP is limiting it, it will start to ramp up, get to a certain point where pellets are filling the pot and the flame is getting nice and high (just starting to shoot out of the pot and stretch to within a couple inches of the heat exchange) and then it ramps back down again. This is with a feed rate of 6 and room temp at 90 or stove temp maxed out too. I've been meticulous about cleaning it, checking it, etc, making sure the ESP is clean, and everything has worked wonderfully but I just can't seem to get it really cranking when I need it. There are no error codes or flashing lights being thrown, it's all operational and working great.

I mean, in a 1300 sq ft house I should be able to keep the place nice and toasty (it's on the first floor living room) even in single digits right? I can't get it above 68 degrees on those days.....

Is there a dipswitch setting I could change or has anyone else run into this problem? Any help would be appreciated.

 

[Mt Bob]

If it is the older 2 knob control board,I would recommend doing the upgrade.If it has the 3 knob,I would replace the exhaust probe,and make sure stove,intake and exhaust are very clean,slower air movement makes the probe think stove is hotter than it is.

 

[PeteFromMaine]

If it is the older 2 knob control board,I would recommend doing the upgrade.If it has the 3 knob,I would replace the exhaust probe,and make sure stove,intake and exhaust are very clean,slower air movement makes the probe think stove is hotter than it is.

It is the newer board with the 3 dials. I know that the air movement isn't an issue as the flame is very responsive and not lazy at all and the stove is piped into a 6" chimney from an old woodstove and the chimney is completely clean as well as the exhaust and all other pipes (I cleaned them in November). Would an exhaust probe cause issues like that? I thought if they went bad it would flash an error code (a certain number of blinks of the light)?

If they're not too expensive and easy to swap I might as well give it a shot.

 

[Mt Bob]

The probes can go bad doing strange things without flashing the code.

 

[PeteFromMaine]

The probes can go bad doing strange things without flashing the code.

Interesting, I'll try swapping it out once I know the color (red or black) to get but it looks like a 25 dollar part, so seems like a worthwhile try!