Harmon PF100 help

[RidgeHome]

We just moved into a house 3 weeks ago that has a Harmon PF100 furnace that was installed back in 2008. I'm having a heck of a time with this furnace and getting ready to call it quits with pellet heat. I had the place that installed it out to look at why it won't light and it lit for him while he was here, when running in service mode but only after he moved some of the pellets around in the burn pot. I can at times get it to light when in Automatic, when set to Auto light but it isn't consistent.

When the gent was out cleaning it/helping me figure out, he said that the feeder wasn't doing a 3 minute 20 second feed on startup which is what he expected. If he pulled some of the pellets up higher in the burn pot, it lit within a few minutes so he thought the igniter was fine, and suggested adjusting the dip switches to increase feed time on start up. He set it up by 1 adjustment and it still only runs for like 2 20 before the feeder stops.

When it does burn, it will run as expected to heat the house for the night and into the next day but while we are away at work, it seems to stop working the last few days in a row and the house temperature drops down to the LP furnace setting which we keep around 60. I have the wall panel set at 69-71 on the Harmon depending on the day as I play with it, but to no avail.

When it stops during the day, it flashes a 5 blink error when I arrive home - which I understand means it didn't fire in a set number of cycles. One time it had stopped and wasn't blinking a code.

It is like the feeder doesn't run long enough to get pellets in the proper spot to ignite, and then on a second try it over feeds the burn pot and raw pellets dump overflow into the ash pan and possibly because of the overfill, the igniter won't light them.

The service tech indicated that it was really clean, and he didn't even clean it while out because to him it looked like it just had been gone through. He checked the draft at the exhaust outlet and it was blowing plenty of air so airflow doesn't seem to be a culprit.

I'm at a loss, I have half of skid of pellets that came with the house, and when it works they produce great heat, but i'm sick of waking up to a cold house or coming home to a cold house. Does this sound like a bad panel that the feeder isn't running long enough even when adjusting the rate +20? I'm at a loss whether it could be a sensor, or control board, etc.

I'm losing my mind here wanting this to work, but afraid to start randomly buying parts to attempt fixing it.

When it was running it seemed like we were burning roughly 2.5 bags a day to get between 67-69 degrees in the house. Its a 2 story colonial with about 2250 sqft upper and 600 finished basement. Is 2-3 bags a day to be expected?

Thanks for any help offered

 

[Watcher1]

We just moved into a house 3 weeks ago that has a Harmon PF100 furnace that was installed back in 2008. I'm having a heck of a time with this furnace and getting ready to call it quits with pellet heat. I had the place that installed it out to look at why it won't light and it lit for him while he was here, when running in service mode but only after he moved some of the pellets around in the burn pot. I can at times get it to light when in Automatic, when set to Auto light but it isn't consistent.

When the gent was out cleaning it/helping me figure out, he said that the feeder wasn't doing a 3 minute 20 second feed on startup which is what he expected. If he pulled some of the pellets up higher in the burn pot, it lit within a few minutes so he thought the igniter was fine, and suggested adjusting the dip switches to increase feed time on start up. He set it up by 1 adjustment and it still only runs for like 2 20 before the feeder stops.

When it does burn, it will run as expected to heat the house for the night and into the next day but while we are away at work, it seems to stop working the last few days in a row and the house temperature drops down to the LP furnace setting which we keep around 60. I have the wall panel set at 69-71 on the Harmon depending on the day as I play with it, but to no avail.

When it stops during the day, it flashes a 5 blink error when I arrive home - which I understand means it didn't fire in a set number of cycles. One time it had stopped and wasn't blinking a code.

It is like the feeder doesn't run long enough to get pellets in the proper spot to ignite, and then on a second try it over feeds the burn pot and raw pellets dump overflow into the ash pan and possibly because of the overfill, the igniter won't light them.

The service tech indicated that it was really clean, and he didn't even clean it while out because to him it looked like it just had been gone through. He checked the draft at the exhaust outlet and it was blowing plenty of air so airflow doesn't seem to be a culprit.

I'm at a loss, I have half of skid of pellets that came with the house, and when it works they produce great heat, but i'm sick of waking up to a cold house or coming home to a cold house. Does this sound like a bad panel that the feeder isn't running long enough even when adjusting the rate +20? I'm at a loss whether it could be a sensor, or control board, etc.

I'm losing my mind here wanting this to work, but afraid to start randomly buying parts to attempt fixing it.

When it was running it seemed like we were burning roughly 2.5 bags a day to get between 67-69 degrees in the house. Its a 2 story colonial with about 2250 sqft upper and 600 finished basement. Is 2-3 bags a day to be expected?

Thanks for any help offered

No help for you yet. U can use the serch button at the top right of this page to see if you can find an answer there. That being said I wonder if the furance has an air motor on it to feed extra air into the igniter? I have that on my PC45, so on the back of the unit is a small box and it has a rubber hose that runs down to the igniter it helps get the pellets going faster. You could look for that and make sure the hose is good and that it is working. Also just check to see if the igniter is in it's proper placement? Also does that unit have a fines box and if so has it been cleaned out? If you have this on a thermostat, is there a way on your unit to set it so it just goes to idle mode like my PC45? I keep mine like that because I don't like it turning on and off all the time/ mine is in my shop now but will be coming up to the house next season after I paint it. Hope this helps.

 

[RidgeHome]

No help for you yet. U can use the serch button at the top right of this page to see if you can find an answer there. That being said I wonder if the furance has an air motor on it to feed extra air into the igniter? I have that on my PC45, so on the back of the unit is a small box and it has a rubber hose that runs down to the igniter it helps get the pellets going faster. You could look for that and make sure the hose is good and that it is working. Also just check to see if the igniter is in it's proper placement? Also does that unit have a fines box and if so has it been cleaned out? If you have this on a thermostat, is there a way on your unit to set it so it just goes to idle mode like my PC45? I keep mine like that because I don't like it turning on and off all the time/ mine is in my shop now but will be coming up to the house next season after I paint it. Hope this helps.

Thanks for the suggestion. I'll look tonight when I go round 8 of trying to figure the thing out.

I did open the fines compartment and clean that out. I think next step is to try testing the esp, and open feed mechanicals and clean them out. I really suspect the main board but don't want to drop the couple hundred to find out im wrong and the installer didn't seem to have a device to connect and check it.

 

[Mr._Graybeard]

The PF100 came with two different igniters over the years -- the old finned igniter that you can access through the cleanout trap under the burnpot surface, and the pressure igniter that has the air pump that Watcher1 referred to. The igniter in that model is a long tube that pumps superheated air through an orifice at the base of the burnpot, right next to the auger.

Since you refer to a 3:20 pellet feed cycle, I'm assuming you have the finned igniter. They're quite a bit slower to light than the pressure ignition. Still, the service tech got it to light, so the system must be operational.

When my boiler has difficulty lighting, 99% of the time I can correct the problem by doing a thorough cleanout of the flue, the combustion fan blades and the housing that the combustion fan rests in. I generally also wipe down the ESP at that time, although the ESP shouldn't affect your ignition cycle.

I am especially conscientious about cleaning the combustion fan blades, like monthly when burning hardwood pellets. That puppy has to be turning at full steam to keep the unit running right. I use a toothbrush to scrub the fan and a putty knife to scrape down the impacted ash on the fan's backing plate. So far this season I haven't had a single misfire that I can recall.

If you want to tinker with the pellet feed at ignition, there are some dip switches concealed behind the label on the control panel that will do that. Wil Lanfear posted a chart showing proper dip switch positions for the different models -- I'll attach it to this post.

You also should be able to keep the furnace running at "idle" when the thermostat isn't calling for heat by setting the toggle switch on the control panel to "manual" once the furnace is lit. I'd only do that at the height of the heating season, though, when the distribution fan is running regularly. I've found that my boiler can overheat in manual mode -- YMMV.

As for consumption, I'd say that it's about spot on for your unit. My boiler will go through four bags on cold days.

 

[RidgeHome]

The PF100 came with two different igniters over the years -- the old finned igniter that you can access through the cleanout trap under the burnpot surface, and the pressure igniter that has the air pump that Watcher1 referred to. The igniter in that model is a long tube that pumps superheated air through an orifice at the base of the burnpot, right next to the auger.

Since you refer to a 3:20 pellet feed cycle, I'm assuming you have the finned igniter. They're quite a bit slower to light than the pressure ignition. Still, the service tech got it to light, so the system must be operational.

When my boiler has difficulty lighting, 99% of the time I can correct the problem by doing a thorough cleanout of the flue, the combustion fan blades and the housing that the combustion fan rests in. I generally also wipe down the ESP at that time, although the ESP shouldn't affect your ignition cycle.

I am especially conscientious about cleaning the combustion fan blades, like monthly when burning hardwood pellets. That puppy has to be turning at full steam to keep the unit running right. I use a toothbrush to scrub the fan and a putty knife to scrape down the impacted ash on the fan's backing plate. So far this season I haven't had a single misfire that I can recall.

If you want to tinker with the pellet feed at ignition, there are some dip switches concealed behind the label on the control panel that will do that. Wil Lanfear posted a chart showing proper dip switch positions for the different models -- I'll attach it to this post.

You also should be able to keep the furnace running at "idle" when the thermostat isn't calling for heat by setting the toggle switch on the control panel to "manual" once the furnace is lit. I'd only do that at the height of the heating season, though, when the distribution fan is running regularly. I've found that my boiler can overheat in manual mode -- YMMV.

As for consumption, I'd say that it's about spot on for your unit. My boiler will go through four bags on cold days.
View attachment 241281

Mr. Greybeard, yes I believe the PF100 we have has the finned igniter. I suspect it has been replaced, along with the firepot as I've been told the firepot is not the original. The way the igniter mounts requires you to remove the pot to dismantle, it does not have the mounting screws through the pot as originally equipped. We looked at it with my inspection camera when the service tech was out a few weeks ago and definitely finned.

I will double check the combustion fan for cleanliness but as discussed above, when the service guy was out he had the combustion fan out and said everything looked fairly clean. On real downfall of this all is the prior owner cheaped out and didn't have dampers put in the duct work so when working on this, the LP furnace pushes massive amount of heat down into the pellet furnace. I'm looking to have the ducting corrected soon as I suspect both furnaces are not heating the house correctly due to pushing heat down into the other non fired unit.

Thanks all for the feedback. If I can't get it fired consistently i may just burn in service mode a few more weeks until the pellets are gone and I believe the unit needs some serious work this summer when I have time to break it down. I know the insulation block by the firepot is deteriorating as well, and I'd like to get to know the furnace better just so I know how to maintain it going forward.

 

[Former Farmer]

You may want to drop the igniter just to make sure that there aren't pellets or fines stuck in-between the fins. I know on my boiler, ash will fall through the pot holes and into the igniter area. While you have the igniter out, make sure all of the holes in the burn pot are cleaned out well. The holes may look clean, but have a ring of carbon built up on them all the way around. You can take a drill bit to clean out the build up.