Newbie Harman PF120

That's a lot of btu's for a 1600 sq ft home. One thing with a pellet furnace or any forced air furnace for that matter is that a lot of people don't realize how much leaky duct work can kill the systems overall efficiency. What was your previous fuel source and how much did you go thru at similar weather conditions? How well insulated is your home? What condition is your duct work in? Does your duct work pass thru any unconditioned space? Are your supply and return ducts located in such a way as to prevent depressurization of certain areas of the home? These are all factors to consider.

Where is your return air being pulled from?

Ok that sounds good, now the big question is are all supply and returns open to each other, in other words do you have any rooms with a door closed that have a supply or return register?

Sounds like your air distribution setup is good.

Do you have your owners manual available? The fire characteristics in the firebox should be approx. 6 in flame and is medium active, not erratic. Factory set is #4 on your feed rate adjustment. My feed limit is set at 3 and normal setting is at 4. Now geographically I live in Michigan's Thumb area and we've been experiencing some bone chilling temps here the last week. Tuesday it was around 3 degrees with the wind chill figured in and I went through almost two bags, so your 3 bags seems a little much in my eyes. Now I've owned this furnace for only two months and am not that experienced in pellets yet (ex- wood burner). Our houses are quite comparable in size and I know I have some insulation issues that I need to rectify in the spring and summer. But I keep my house at 72 and this thing doesn't miss a beat. I have experimented with some pellets and found that somersets and kirtlands are a very good pellet they are both neck and neck. Pro pellets from tsc are dirty and I burn more of those in comparison to the other two. I'm not sure what pellets you are burning but you may want to consider that.

The flame does not look very good to me. Your duct work looks like there is a reducer in it. Did the installer put in the manual or auto dampers in the duct work, these prevent the pellet furnace from recirculating warm air through your primary furnace. Either damper will work one just costs a lot more than the other. I think the first thing I would do is completely clean the unit, then look at what pellets you are burning. An inferior pellet will require an increased feed rate and will require more frequent cleaning. The one thing I'm finding out quickly is that not all pellets are created equal. If I buy a ton of pellets at lets say $220, but for another $30 a ton I can get a superior pellet I'm going to spend the extra $30 bucks because in the long run its saving me a lot of grief. As far as the red silicone gasket inspect it for defects but most importantly make sure it's clean and that when the swing the burnpot back that the latch fully seats. If you do suspect a faulty gasket then I would contact the installer I'm sure that would be under warranty.

Here's a pic of my flame and the manual dampers installed separating the harman from my lp furnace.

Steen:
I am a newbie to this forum and to the Harman PF120 as well, tomorrow (12/12/14) will mark one full week since I have been using the PF120 to heat my house. My home is an old 2 story renovated farm house, approximately 2400 sq ft plus about 600 sq ft of unfinished basement. I have been running my fan limit switch at 150 deg F start and 90 deg F shut-off. I came up with settings by checking my plenum temperature and output grille temperatures with a digital volt meter and a temperature probe. The internal plenum temperature is actually at about 170 deg F when the fan first kicks on and drops to about 100 deg F when the fan finally kicks off, the plenum temp stabilizes at 115 deg F through the middle of each cycle. My register temps on the first floor are around 110-115 deg F, dropping to 90 deg F right before the distribution fan shuts off, temperatures upstairs are with a few degrees of these. I had been running my max feed limit dial at the factory suggested number 4 setting. With these setting I am going through about 3 bags (120 lb) of pellets per day, our outside temperatures have been in the mid-30's during the day and mid-20's at night. I will be playing with the feed limit dial in an attempt to save some pellets.

Also in regards to the flame shape, I too have noticed my flame seems to roll slightly behind the burn pot almost in between that piece of sheet metal. My flame also seems to come over the side of the burn pot towards the viewing window some, I will try to take and post some pictures later.

New owner of a PF120 here as well. I'm burning through more pellets than I thought I would too. I have an old farm house, approximately 1900 sq/ft in size. Average temps have been in the mid to high 30s since it was installed on the 13th. I'm going through 2 to 3 bags a day. What's really irking me is that the furnace will keep the flame going for hours with the blower never kicking in. I keep trying to tweak the fan switch, but so far to no avail. The thermostat temp is satisfied throughout, so I'm struggling to understand why it just keeps burning pellets seemingly nonstop. Time to have the installer come back and check things out, I suppose. Let me know if/when you find the magic settings.

skidadil:

I've been averaging 2.8 bags per 24 hour period over the past 2+ weeks with my PF120. Outside temps averaging in the low 30's, thermostat in living room set at 72-73. Fan limit switch is at 90/160. My furnace "idles" with a small flame when not being asked for heat by the thermostat, when it's doing this the auger runs for a second or two approximately every 20 seconds, feeding in just enough pellets to keep a low fire burning. If it stays "idle" for around an hour it stops feeding pellets and the fire goes out, this usually occurs on warmer days around 11 am. Around 4 or 5 pm when the house starts to cool down the furnace will reignite itself and go back to heating. Through the night it seems to blow heat for maybe 10 minutes every half hour or so.

When you so the furnace will keep the flame going for hours without the blower kicking in, how large is your flame? Are you running yours in automatic or service mode?

PS I had a service tech from my dealer here yesterday just to double check everything and look at my concerns with the flame pattern/shape, he assured me that everything was working as it should.

I'm currently running me feed rate at 4, I've played around for several 24 hour periods with 3.5 and 4.5, not noticing much difference in pellet consumption. I was told by service tech that I could run it down at 3, however when I tried this it caused my distribution fan to cycle on and off once or twice before the furnace built up enough heat to keep the fan on for it's 10 minute run.

I have a moderately insulated home and heat about 3000 sq, ft, with a similar heat source. Though the PF120 is a furnace, my PB105 is currently burning about 2.5 to 3 bags per day. 2 to 2.5 on 35 degree days and one more at the 15-20 degree days.

elevenMracing said:

skidadil:

When you so the furnace will keep the flame going for hours without the blower kicking in, how large is your flame? Are you running yours in automatic or service mode?

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My initial flame is very large. It looks like a blazing fire. It reaches the thermostat setting very fast, and then the flame gets reduced to a medium to low size. I'm running in automatic mode.

I changed the fan/limit switch to 80/150 and the feed rate to about 4.5 (although I think I'm going to bump the lower limit up to 85 or 90). That helped to keep the fan blowing while it was still feeding pellets (as opposed to have the furnace flame go for hours without getting any heat through the ducts). Up until today I thought that resolved my problem.

Overnight, I set the temp to 66 degrees and then to 72 during the day. I had a lazy morning this morning, so I didn't wake up until around 9:15. The furnace was on at that time. Around 10 AM (while it was still on) I bumped it to my daytime temp of 72. It's not 1:50 PM and it has been running non-stop. So, the furnace has been running nearly 5 hours (perhaps longer, since I don't know what time this morning it started up). It reached 72 degrees probably within 15 - 25 minutes when I set it to that around 10 AM. I just don't understand why it keeps running for so long. Granted, it's doing a great job of keeping it right at 72 degrees. But elevenMracing says his runs for about an hour after it reaches the set temp and then shuts off. Mine does that some times, but not consistently.

I have two more things that I want to try. For one, my fresh air intake pipe was installed longer (~18 - 20' w/ 3" pipe) than the maximum length suggested in the installation manual (15' w/ 3" pipe). So I want to reroute that to get it to 15'. Secondly, I think I have a low to medium quality pellet. It has very low ash (I only filled up around a third of the ash box over two weeks), but the pellets look very inconsistent ... and there's even some corn mixed in with it. I want to try a high quality pellet to see if getting a consistent fuel type will help anything.

In the five hours it's been running:
1. Has the distribution blower been running at all after your house reached it's desired 72 degrees? If the distribution blower stayed running for 5 hours bump the low setting of your fan limit switch up to 90 or 100 as 80 may be too low, in which case the distribution fan will run forever as it can never reach the bottom limit.

2. Has the fire in the pot just been a small idle fire that entire time?

3. How often does your auger motor run?

My initial flame is very large also, I'm sure that is due to the large amount of pellets the the auger motor pushes into the pot initially. There is an adjustment for this on on the card somewhere, I plan on playing with this in the future as I feel the burn pot in mine gets excessively full during the initial stages of the high fire and then burns back down to a medium amount of pellets in the pot, which it maintains until the furnace puts the fire/auger back into idle fire.

elevenMracing said:

In the five hours it's been running:
1. Has the distribution blower been running at all after your house reached it's desired 72 degrees? If the distribution blower stayed running for 5 hours bump the low setting of your fan limit switch up to 90 or 100 as 80 may be too low, in which case the distribution fan will run forever as it can never reach the bottom limit.

2. Has the fire in the pot just been a small idle fire that entire time?

3. How often does your auger motor run?

My initial flame is very large also, I'm sure that is due to the large amount of pellets the the auger motor pushes into the pot initially. There is an adjustment for this on on the card somewhere, I plan on playing with this in the future as I feel the burn pot in mine gets excessively full during the initial stages of the high fire and then burns back down to a medium amount of pellets in the pot, which it maintains until the furnace puts the fire/auger back into idle fire.

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1. Yes: it ran the entire time. I figure that I might as well get my monies worth with the pellets burning in idle mode, so that's why I set it so low. I do, however, think I set it too low and will bump it up slightly.

2. It's a relatively small fire the entire time.

3. I haven't timed it at all. As these things typically go, as soon as I posted my previous reply the furnace shut off. lol. I'll pay attention to the frequency the next time it fires up. If I had to guess, the auger runs every few minutes when it's idle, but I'll get a little more scientific and reply back.

Sounds good. Definitely adjust that lower fan limit switch setting up to 90 or 100. I'm guessing running the distribution fan with an idle fire in the furnace doesn't generate much if any heat out of your ducts. During an idle fire my auger runs once or twice every minute for a few second each feed cycle. I am guessing that my idle fire goes out about an hour if there is no call for heat but I don't know that for a fact as I've never sat down and watch the entire process. One other afterthought: have you cleaned your ESP? I believe this is what determines how often/how long to run the auger motor in an attempt to maintain a certain exhaust/fire temperature in high fire and idle fire modes. I am guessing a dirty ESP could cause the furnace to feed an excessive amount of pellets as a large amount of ash on the probe would basically be an insulating blanket causing it to see a lower temperature than was actually present in the exhaust stream.

Two bags in 24hrs is probably about right for your square footage. I go through between 2.6 and 3.8 bags a day depending on outside temp heating 3000sq ft. I beleive the heat setting should remain at 4 when using the wall thermostat, I haven't touched mine. If I remember correctly the owner's manual made mention of that somewhere.