help with harmon pf100

Perhaps posting this to the boiler forum would get some feedback. This forum is mainly freestanding stoves and inserts. I'm interested to see what folks think of the PF100, or the PB105

There are a few people over at iburncorn who have the pf100.
Check it out: http://forum.iburncorn.com/viewforum.php?f=12&sid=ead148596f4d8dbacf2d0ac605cc6836

I also recently installed a PF10O...am using about 2 bags/pellets a day, depending on outside temp.
Are you running off the thermostat? if not that could be a big factor. I like the unit...it really cooks compared to my old unit.

I don't know anything about adjusting the cold (combustion) air intake, I have no dampers on the flu, just a T elbow to my chimney...about 2’ up and 3’ over.

Have you tried lowering the thermostat way down? I don’t think it’s a particularly accurate item. I keep my thermostat pegged to the lowest temp!

Anyway the combustion fan is always on, it has 1 speed only. Once the house heats up, the flame does die down and the feed rate slows. If the house gets really warm, the unit actually shuts down, then restarts when the house needs heat again. When the furnace is really cooking, the flame is very strong at 45 degrees.

Have you done a clean out yet? The cleaning instructions mention removing a flame guide but I don’t know what that is?

Firestarter, I must be missing something. I assume you have your furnace hooked up to a duct system that distributes warm air throughout you house? and you also have return ductwork that brings cooler room air back to the furnace? Assuming the heat-exchanger is working properly, and the blower fan (not the combustion fan) is on, and the ductwork is right, the only hot air going up the chimney should be the combustion air. BTW, I keep my thermostat at a lower temperature.

I had a PF 100 installed and began running it in November. Large house, though, probably more than 4000 square feet, nine foot ceilings downstairs, wide open two story foyer--your basic heating nightmare. I've been having some of the issues I see described by Firestarter. Hot air leaks from the burn chamber. My dealer said it's normal, though I didn't believe that. I checked the rope gasket, and it does seem to be a bit more crimped along the top.
I insulated behind the thermostat, and I have to say, that has made a tremendous difference. The downstairs now heats up to 70 a lot more quickly in the morning than before (it used to take up to 3 hours to get up to 70, even if the room temperature was already at 65). That thermostat, by the way, is about five degrees off. Its 65 is actually 70.
At times, I can burn through 4 bags of pellets in 24 hours. But a few days ago I finally adjusted down the feed rate to 2 1/2 and that seems to be making a difference. It also depends on how far down I turn the thermostat at night. Recently, I haven't been turning the dial alll the way down, because when I have in the past, there have been about five occasions that the unit has failed to automatically relight during the night. I come downstairs in the morning to a cold first floor, and the status indicator is blinking 4 times. So I have to clean out the burnpot and do a reset. I can get no straight answer from my dealer on this (or anything else for that matter), but for some reason, the unit gets a little tempermental when the dial is all the way down.
I am saving a load of money by heating with the PF 100, and that's a great thing (our primary heating system was propane furnace). But it hasn't been totally trouble free. Anyway, I appreciate hearing what other PF 100 owners have to say.

propanevictom - good comments. I keep my thermostat set to min without any issues, and yes it is not accurate...about a 5 degree error. I will try adjusting the feed rate to 2.5 and see if it makes a difference in how much fuel I consume. the pf100 pumps out the heat fine and I find that the cleaning is not too bad. my dealer is not very well informed and when I tried contacting Harman directly, they told me to call my dealer! yes there is air blowing from the door but I am not too concerned about this...maybe I should be? I have a question...the manual makes reference to a 'flame guide' do you know what this is?
thanks

My last 160 pound fill would have lasted (I estimate) for about 40 hours. I'd have pushed it to the limit except I didn't want to stay up until 2:00 in the morning. Ran it most the day with the feed rate set at about 2.
I have seen reference to the flame guide only in the online how to clean the PF 100 pdf file from Harman. My printed manual makes no reference to it at all. Since encountering it in the pdf, I too have wondered what this device is.
Although my dealer is not very helpful or reliable, they did recently me get me information on how to wire-in a programmable Honeywell thermostat to work with the Harman thermostat. They also got me information about Harman's bulk feeder/hopper which will work with either the PF 100 or PB 105. Goes for about $1600. Link below (scroll down a bit):
http://woodpelletguru.blogspot.com/

I would be very interested to know more about the Honeywll thermostat retrofit, thanks.

Yes the flame guide is only mentioned in the cleaning document, not the owner's manual (which I find to be poorly written).

What kind of pellets do you use? I have had good results with 'New England Hardwood' brand. Recently got a ton of less expensive Pinnacle softwood pellets, which seem to produce more ash and crud in the burn-pot.

What speed do you have your blower on? I use low, thinking that it will make for warmer air?

Thanks

I'll see what I can do by way of getting you the schematic for the thermostat. It was an official Harman tech bulletin. They recommend the Honeywell RTH 230 B or the RTH 6300B (though there's no need to pay for the more expensive 600). I haven't actually installed it yet. The greatest benefit should be that the temperature will automatically increase in the morning. I'll see if I can scan the thing.

I've been using Pennington pellets, simply because Sam's Club (and Home Depot and Lowe's for that matter) sell them. They're made from the sawdust of oak--the company gets the saw dust from an oak hard wood floor manufacture. I've gotten them for under 4 bucks a bag, paying something like $194 a ton. I've seriously considered Pelletsales.com, but with the shipping fee per ton (sometimes 40 bucks or more), I'd get slammed on overall price.

I've been running my distribution blower on high all season long. Dealer said to keep it on high, but that's really not good reason to. I'd be interested to hear what kind of results you've noticed running it on low. The fan pulls something on the order of 500 watts--generally speaking, and my electric bills have been a bit higher this year. Are you saying that if it's on low, the house won't be as drafty.

I was advised to keep the distribution blower on low because, according to the dealer, the slower moving air will have more time to warm up...not sure if it's correct but that's what he said.

I checked the manual and there is a part number for the flame guide. I asked my dealer and he said there is a flame guide that on the pf100 is bolted down, but on other Harman stoves it can be lifted out. Still don't know which part it is...I'll look into it further.

the flame guide is the cast iron plate that sits on top of the burnpot (where the fire happens). It directs the flame out towards the combustion chamber and away from the hopper area.
If your unit is installed properly the ESP Probe will prevent the machine from running at an extreme burn and throwing excess heat up the exhaust pipe. The probe measure the heat of the exhaust to ensure that it stays in a good working range.
Is it possible you have the unit in service mode, forcing it to work at a constant speed?

Here is what I have about the programmable thermostat

John


Don't like the Room Sensor setup because I neglect to turn down the thermostat when I'm not going to be home(waste of pellets). I wanted to replace this RS with a programmable thermostat. So I did and I want to share this. A Harmon Technical Bulletin actually addresses this. Acquire any 24v/millivolt programmable thermostat and desired length of two-wire thermostat cable. DO NOT DAMAGE or DISCARD RS probe. Its needed for this mod. Unplug stove. Remove and cut only one wire of the two wire RS cable. Do not alter the probe end. I did this at the stove connector end. Splice one wire from programmable thermostat to one end of this "cut wire" and splice the second wire from the programmable thermostat to the other end of this "cut wire". Reinsulate the cable assy to suit, reinstall on stove, install programmable thermostat whereever and wire to suit. With the programmable thermosat either off or at a temp setting lower than programmed, plug the stove in. I had a 3-blink status light alarm. This alarm indicates that the RS is either disconnected or faulty. Activate run-program or turn on programmable thermostat and the blinking sequence stops. The programmable thermostat is now only a relay that opens or closes the RS circuit. The RS is still monitoring room temperature. Position it accrdingly. The Bulletin states that the RS must be installed in-line as described for this to work.

Delta T
Is the cast iron flame guide you are describing for the PF100? There is no flame guide above the burn pot on my PF100, only a brick block.
Thanks

Underneath the brick should be the flame guide, just behind the flame guide should be a white (when its clean) ceramic insulator.
The burnpot design oan flame guide setup are extremely similar on all Harman pellet stoves. The flame guide should be sitting at about a 45 degree angle towards the back or the burnpot. ON page 28 of your owners manual in Figure 57 is a picture of the burnpot, the flame guide is the item on the upper portion of the pic. The bracket that hold the 9x4.5 inch brick also hold the flame guide and insulator in place.

thanks, I'll check it out when I get home. I have lifted the brick out while cleaning the burnpot, but don't recall a flame guide specifically.... I'll try taking a pic and post it so you can see what I've got.

So basically, you're saying that the flame guide is there, just not so noticeable, right? Is the thing adjustable? By the way, what's the function of the brick? It sits entirely above the flame and burnpot. Am I missing something?

I have to say that Harman's recommendation that the feed rate for the PF 100 should be set on 4 ridiculous. I'm thinking that 4 was actually overfeeding the burn pot and flame and may have been the cause of the unit failing to automatically reignite during the night on 5 different occasions. Unit seems to be burning much, much more efficiently, cleanly, and with a lot less smoke coming out of the vent. What was Harman thinking? I've been running the unit at just above 2 for over a week now.

The flame guide is sort of not noticable. It is also not adjustable. It functions as a deflector to force the flames away from the back wall. The same goes for the brick, it insulates heat from transfering through the stove body into the hopper. Neither really controls the burning or lighting of the machine to much degree. Most of the reasons that I have seen the units fail to light is because ashy material is built up around the ignitor (accessible through the little door in the face of the burnpot) Also if your pellets are high in mineral content they can cause "carbon" or slag material to fill up the holes in the burnpot. Because the ignitor works by super heating the combustion air as it enters the burnpot, if the holes are plugged at the base of the burnpot, the air seeks the path of least resistance which is the holes at the top of the burnpot. If no pellets are sitting right on those holes the air has nothing to ignite. That being said, ignitors do fail, and if yours fails no manner of scraping or cleaning with make it work. The "normal" setting on the feed contol is not for everyone. Some consideration has to go into how your system is set up and how hot you want the air coming through the vents. The same can be said for the fan speed.

Thanks for the info. I've been wondering just how the ignition process works. I'll check the holes in the burnpot next time I clean it. But given the tight space, they're really hard to see. Is the burnpot something I can easily remove to fully inspect and clean?
I have noticed that when the unit relights, there is an intense rattling and shaking. (The little metal flap at the bottom of the burn chamber door rattles back and forth like crazy. Seems like the unit can't catch its breath). Rarely does it reignite quietly and smoothly--as it did the very first time I lit it up. Instead, the flame will appear and then disappear, then there is rattling and shaking--not of the entire furnace, but within the burn chamber. I can hear it from upstairs. I told my dealer about this months ago, and he ordered a replacement feed motor without coming out to see and hear the problem. But it had nothing to do with the feed motor. It still happens. It doesn't seem to be right to me, and I'm wondering if this has something to do as well with the unit failing to reignite.

There is a small flap on the door to the combustion chamber that can rattle when the machine ignites because of the rapid change in pressure when ignition happens. If your burnpot is really dirty a huge amount of potential energy is building up before ignition and then the gasses are rapidly expanding on ignition. The burnpot does not come off easily, nor should you really have to take it off. Use a screwdriver (flat head) to scrape the burnpot, Use a small allen wrench to clean the little holes and then take the little door off the face of the burnpot and empty it out. I use a flashlight and shine it into that little door and if you can see the light coming through the holes then that probably good. A small mirror can help you look into the burnpot if you like. The more minerals you have in your pellets the more you'll have to do this process. I know people who do this evey week and I know people who do it 2 times a year so there is a huge variation.

for you guys that menyioned tha the thermostat is off by 5 degrees.. well- mine was too-- but tehre is a way to fix it

one method --> unscrew teh set screw on teh knob of teh thermostate and turn it down 5 degrees- then retightrenn -- siomple and effectiove...

second method-- on the control panel of teh furnace there is a dial that lets you compensate for this difference. Ity isn;t documented worth diddly in the manual- and most dealers dont; know anything abotu these furnaces..
I dialed mine down -3 -- and that took abotu a 3 degree swing out of the thermostate that was running hot...

make sense?