Help me diagnosis a PF100?

[a5t1]

I just bought another PF100 to heat my shop, unfortunately, it doesn't work. Here's the deal:


I plug it in and switch the main power switch to on
The power light comes on
the status light come on
the combustion motor turns on (which is strange as the barn is about 30 degrees right now)

About 1 sec later
The status light goes off
The combustion motor turns off

Then the next second
The status light comes back on
The combustion light comes back on

and that's it. The feed motor light lit up once out of maybe 5 or 7 tries but the feed motor didn't actually turn on


This is a used unit that I just installed. There is a dealer about 40 min. away from me who said he's never worked on a PF100 but would let me use the Harman diagnostic tool...can anyone give me direction?

 

[SmokeyTheBear]

Is it in test mode by any chance?

 

[a5t1]

I put it in test mode, same thing happened.

I also tried the blower motor, it doesn't work. (I flipped the switch on the thermostat that screws into the supply.)

 

[SmokeyTheBear]

I just want to know which mode the unit was in.

After it has been moved the very first thing to do is to clean the unit as moving will dislodge anything inside the units air paths which will dump crud in all the wrong places, then you need to go over the wiring as anything with a circuit board that stuff plugs into may have been loosened by a move.

I would not trust any blower tests that are run using just the stuff on the stove until I was certain it was all there and connected.

When started the unit should turn on the combustion blower in order to produce a vacuum (pressure difference) to enable that auger to get power and turn delivering pellets for the igniter to cook.

 

[a5t1]

I'll look it over more tomorrow. I have the thermostat hooked up and then using the automatic setting. "4" for the feed and "normal settings" for the other knob. I'll clean it thoroughly tomorrow and go from there. I check all wiring, hooked up the blower and tried to check it using it's thermostat.

Any tips on using the dealer's diagnostic tool?

 

[SmokeyTheBear]

I'll look it over more tomorrow. I have the thermostat hooked up and then using the automatic setting. "4" for the feed and "normal settings" for the other knob. I'll clean it thoroughly tomorrow and go from there. I check all wiring, hooked up the blower and tried to check it using it's thermostat.

Any tips on using the dealer's diagnostic tool?

Nope have never used one or read the manual for it. But it will let you know what the controller thinks of things, there are a number of Harman folks (service folks here and elsewhere who might look in on the thread). I'm not one of them. I just ask a pile of questions or work on general stove burning issues.

 

[a5t1]

My concern is that it powers off for 1 sec and then turns back on. I hope it's not the control board...

 

[James Andrew]

I have a pf120 so I assume they are basically the same. You don't use that plug to provide power to furnace. The furnace gets hard wired in. The plug is there to use a backup battery source for a proper shutdown if you lose house power. If you just plug into an outlet the control panel will light up but nothing will work..If you don't use a battery backup the plug goes into an outlet on the side of the power box. If you need more info let me know.

 

[a5t1]

Ah, interesting, thanks.

I checked all the junction boxes and the ground had come out of the front, the blower motor had disconnected from the rear. After double checking the owner's manual, everything is now working.