How long does your burn pot last? Specifically on a harman PC45.

[OverlookEGR]

I just bought a house which has a pellet stove in it (a harman pc45). I don't know exactly how old it is, but it is at least 4 years old. I have put almost 3 tons of pellets through it this year. It has two different burn pots. The one with the larger holes is the one using for wood pellets. And one with smaller holes. By holes, I mean perforations. And the harman dealer near here says that the manufacturer is now saying to leave the "stir stick" in even for pellets.

My burn pot is starting to show significant cracks between the holes in the back near the auger where the fire is hottest. I'm thinking about drilling out the other one that is meant for corn. It has smaller holes and doesn't work well with pellets. Does anyone have any thoughts?

 

[Bioburner]

I bought a used PC45 with the crosslink and it was two seasons used and now I am into 3 seasons use. I see little wear and burn close to 50% corn without a stirrer. Now there was a upgrade kit that left the end of the tray open for ash to dump off from. The picture show the pellet tray with the upgrade of the cap. Seems to allow the burn pile to get farther out and not get a pile of hot coals at the auger mouth. If your not planning on ever trying to burn straight corn I would go ahead and bore out the holes. There is a change of dip switches also to change the feed.
Something else to consider is that stove can be changed to the P61 with Harmans pot and a new control board and couple other things if and when the expensive air pump goes taking the igniter with it.

 

[OverlookEGR]

I have that upgrade kit, but I was having trouble with burning material falling over the edge. I am operating my stove on room temp with the temp sensor across the room on an inside wall about 4 ft off the floor. I also have a ceiling fan that I run on low or medium all the time. I keep the room around 69-70. I've been running the blower on medium and the auger feed on the line between 3 and 4.

Here is a pic of how my stove is now. This is when it it idled back, not burning hard. I did clean out the stove completely this fall before I started using it. I didn't remove the ESP though. I clean out the stove every now and then. If I notice a build up of burnt ash, I have scraped the burn put in between cleanings.

How do you run your stove? Does it ramp up and burn hot sometimes? Does the ash spill over?

(broken image removed)

 

[Bioburner]

I will PM you

 

[OverlookEGR]

Can you tell me more about your crosslink? Maybe this summer I could put one in my stove and run it to my kitchen floor?

 

[jp99]

And the harman dealer near here says that the manufacturer is now saying to leave the "stir stick" in even for pellets.

Interesting. I never use the stir rod when burning mostly pellets, but the large hole pot and the small end cap. I never have had the fire fall off the end. I think two of the DIP switches - 7 & 8 - control how quickly the feed rate changes and that might help. Somewhere on this site is a list of what each one does.

I would think the stir rod would break the wood fire up too much. The corn of course needs it.

I do run in stove mode though, not temperature mode. I have a consistent burn rate because of that.

With 100% pellets, I find the ash residue can become hard and block proper movement of the ash. Hence I use 10-15% corn and it breaks the ash up nicely. I have a good movement of ash off the pot this way.

 

[Bioburner]

Interesting. I never use the stir rod when burning mostly pellets, but the large hole pot and the small end cap. I never have had the fire fall off the end. I think two of the DIP switches - 7 & 8 - control how quickly the feed rate changes and that might help. Somewhere on this site is a list of what each one does.

I would think the stir rod would break the wood fire up too much. The corn of course needs it.

I do run in stove mode though, not temperature mode. I have a consistent burn rate because of that.

With 100% pellets, I find the ash residue can become hard and block proper movement of the ash. Hence I use 10-15% corn and it breaks the ash up nicely. I have a good movement of ash off the pot this way.

What feed rate,but remembering that as the manual states needs to be adjusted to fuel?

 

[jp99]

What feed rate,but remembering that as the manual states needs to be adjusted to fuel?

For pellets with 10-15% corn, I have the feed set to 1.5-2.5, and stove setting of 1.5-4, depending on outside temperature.

(Edit - that is with large hole pot, large hole combustion fan plate, and pellet end cap)

 

[Bioburner]

I use fuel setting of three with close to half corn that has a RM under 10 percent. When mixed with Indeck pellets this year have a very nice tan ash in stove.

 

[jp99]

That's a good setting and result. I'm not sure my corn is much under 14 RM.

Of course the feed setting is a max anyway.

Do you run in temperature mode, or stove?

And OverlookEGR, I've been using my PC45 since 2008. No cracks or issues with my large hole burn pot over the years. In corn mode I usually run the small hole pot, but until a month ago I had run mostly pellets for the last 4 years with the large hole pot. I do keep mine somewhat cleaner than yours though to extract the heat more efficiently.

 

[SidecarFlip]

"That's a good setting and result. I'm not sure my corn is much under 14 RM."

You do not want to be burning 14 RM corn, way too much moisture and way too much nitric vapor being given off in combustion. You need corn below 12%RM to achieve a good burn, no exceptions.

In Post Number 3, the stirrer rod (agitator) is exhibiting definite signs of oxidation from an oxygen rich (oxidizing flame, why the ends of the prongs are tapering off. Ideally, you want a neutral flame, not oxidizing and gasification above the fuel bed when the stove is operating wityh a falme thats not lazy but not a ,blow torch' either (and that applies to any stove, not just a Harman

That can also be why your fuel pot is degrading, it will oxidize just like the stir rod does, from an oxidizing flame.

Years ago, I thought I was doing the 'right thing' by dialing in the air and driving the flame. Actually, all I was doing was eating stir rods and making funky fuel pots. I stopped doing that a few years back (throttled the air back) and my heat output increased and 'consumable parts' became non-consumable.

The above apples to any make.

Interestingly, I run 2 pots, switching out one for the other at cleaning and soaking the pulled one in water to loosen deposits and both my pots are large hole. I found the large holes make it easier to control and add underfire oxygen.

 

[OverlookEGR]

Thanks for the input sidecar. Maybe I should put the combustion fan cover plate with the smaller opening in then? I don't really know how else to control the air on this stove. I burn straight pellets and have no real plans to burn corn.

JP99, I suppose I would do well to keep my stove a little more clean. Right now, I empty the ash bucket every 10-12 days and about every other time, I scrape the heat exchanger. I scrape the burn pot more often though. The pic does show a build up of ash.

I want to maintain the stove well, but I don't want to spend more time than I need cleaning it.

 

[Bioburner]

One has no control over the air in a Harman other than the exhaust plate and that may be the issue as the ash in the tray is being trapped and reflecting extra heat back and the extra stirring inputs more air and causing IMO your degradation. The large holed exhaust plate is for the upgrade with the open ended burn tray. Like adding a turbo to a engine and not changing fuel settings so things get hotter.
I clean the exchangers everyday as the crosslink collects ash pretty fast and brush the pot, but the total time for that is only about 15 seconds. Total cleaning is about every three weeks and ash bin is full usually in a week with corn blend.

 

[bags]

These guys are the ones you want to listen to on the corn burning and or mixing with pellets. Bio has your exact PC45 and so do I. I have burned a 50 / 50 mix of corn and pellets in both my PC45 and P68 without an issue but have not done it a bunch yet.
I found that running the pellet pot and large hole exhaust plate in the 45 works well. Get rid if the end plate and go with the pellet set up if that is what you intend on burning. The end of the pellet pot is open and there is no need for the agitator or "stir stick" when operating like this.

I have ran numerous bags thru the 45 this way and it operates much like my new 68 when configured with the proper pellet burning set up. The pellet pot does have larger holes and a small retaining clip at the end of the pot that is flush with the pot's bottom. Ash and stuff pushes right off and over with it. Cleaning and scraping is easier too. From the looks of your photo you need a clean and should do a good one at least every ton burned. Also do the weekly tune up of a quick clean of the fire box and all for best burning results.

BTW, Welcome Overlook! Bio can give you some good quick and easy tune up tips and get you running well. Rona also knows the PC45 well and some others here. It will help you tremendously to do some of this stuff (cleaning and checking over things) and familiarize yourself with your 45 and prevent unnecessary glitches and heating delays. Good Luck!

The pots and stirrers are wear items and do need to be replace in intervals. Bio has good recommendations as to where to find them and myself and others can offer suggestions. You have found the right guy for questions on the 45 so PM Bio as he has suggested so he can square you away. I do know corn is a lot harsher and tends to wear pots, stirrers, and stuff quicker but with proper cleaning you can get a lot of time from them.

 

[jp99]

JP99, I suppose I would do well to keep my stove a little more clean. Right now, I empty the ash bucket every 10-12 days and about every other time, I scrape the heat exchanger. I scrape the burn pot more often though. The pic does show a build up of ash.

I want to maintain the stove well, but I don't want to spend more time than I need cleaning it.

I agree Overlook - I don't like cleaning the stove. It's more that I have to than I want to.

With 80% corn I'm emptying the ash pan every 3 days and doing a quick vacuum of the bottom section. I shut down the stove once a week for a complete cleaning in the top section and to swap in a clean stir rod. When I burn 85-90% pellets I go a month before emptying the ash pan. In either case I clean the heat exchanger every 2-3 days for efficiency, though the lighter ash of pellets fouls it faster than corn ash. Sometimes with pellets I clean the heat exchanger daily.

Corn is definitely more cleaning work, but at $160/ton vs $250 for pellets it's worth the time.

 

[jp99]

One has no control over the air in a Harman other than the exhaust plate ...

Not quite - DIP switch 4 also adjusts the airflow. If it's set On you can hear the combustion fan speed increase.

 

[Bioburner]

That may be true but what other changes in the burn algorithms? Without a DDM or data from HHT we are shooting blind

 

[jp99]

That may be true but what other changes in the burn algorithms? Without a DDM or data from HHT we are shooting blind

I'm not sure about the newer boards. I have the old model and the data in the old "I Burn Corn" forums from 5 years ago indicated DIP 4 on set the combustion fan voltage to full, and switch 4 off made the voltage variable. That will affect how the system responds as the ESP temperature will change, but it's an end result of the airflow change.

 

[SidecarFlip]

I don't own a Harman (might in the future) in as much as I like them but need to save the green stamps to get one...lol, but I've roasted corn and a corn pellet mix in my USSC for at least 15 years so I have a pretty good handle on what different varibles when it comes to combustion aie=r, corn moisture and pellet quality do and how they impact not only heat output and ash buildup but also how the stove components that are subject to the heat of combustion react.

The principles of combustion remain the same across every stove, boiler or stand alone. Different stoves control the facets of combustion (combustion air, feed rate and ash removal) in different ways but the combustion air must be controlled to a point where the flam is non oxidizing ot your slowly destroyall the components in direct contact with the burn itself, the stri rod, , burn pot, ebd of the auger and to a lesser extent, the internal baffles in ths tove itself, that the flame actually comes in contact with (thats called impingement btw).

No matter what brand, you will become a 'slave to the stove' because it has to be cleaned regularly but the frequency of cleaning is dependent on one, design, two quality and ash content of the pellets used and three, the corn (if used( and the RM of the corn as well as test weight (test weight is the measure of the 'meat' inside the husk. Thats what burns or in proper terms, 'carmelizes' and makes heat and the residue or what you get after the g burn from corn is the husk.

Any corn burned in any appliance MUST be clean either with an corn cleaner or by the provider, in my case I have corn delivered and tanked that has been cleaned for animal feed, both magnetically and with vacuum, removing cob pieces, stones, hardware, leaves and any other junk from the field. You can't butn corn direct from the field, it has to be cleaned and the moisture must be below 12% to combust properly.

Bio can instruct you on how to tell if the corn is in the proper burn range with the 'pliers test', or invest in a moisture meter. I use a Delmhorst but it also gets used in my farm business.

 

[SidecarFlip]

Bio, Rona needs to jump in this thread, want to PM him or should I do it?

 

[Indiana]

This is my 5th season and I am on my 2nd burn pot. The second pot is already in poor condition. I will need a new one before the next heating season. The pot itself stays in good condition, but the top ring degrades and wears thin. I think due to my letting ash build up between The front of the ring and the air wash deflector plate. I only shut my CPM down on Sunday mornings.

 

[Bioburner]

Bio, Rona needs to jump in this thread, want to PM him or should I do it?

I have been trying to make most of my replies to the thread applicable to the OP who burns only pellets. The PC45 is a bit quirky. I have used three different ages of CB and all burn a bit different. If I hadn't had to buy a new board this season I would have bought a DDM and would be able to get more info on its settings and configurations. Might be the reason Harman decided to stop manufacture as the many options caused to many headaches when owners don't use the accessories as the manufacture states. Easier to just mount a pot, install one exhaust plate, and one set of dip switch settings, and get out of the dedicated multifuel with its set of headaches of how dry and how many chunks etc.

 

[johninwi]

The large hole burn pot holes are 1/8" (0.125"), no sense in just letting it sit on the shelf, drill it out. A new burn pot is $60 from my dealer.

The small hole exhaust plate does work better for my setup, test it.

If you running room temp and pellets are falling off the end of the pot reduce your feed about a half point, keep droping it back till your about an inch from the edge of the pot. Using the short end plate and no stirrer may reduce the blown around ash too, let it fall straight to the pan.

I have 4 years on a pc45 burning pellets, i have no damage to the burn pot like you describe. I had experimented with the stirrer and it isn't helpful for pellets.

There had been a thread about the harman pb105 furnace cracking the burn pot, the factory fixed that by adding ribs across the bottom of the pot, i guess it helped absorbe some of the heat and the steel didn't deterioate.

 

[SidecarFlip]

The large hole burn pot holes are 1/8" (0.125"), no sense in just letting it sit on the shelf, drill it out. A new burn pot is $60 from my dealer.

The small hole exhaust plate does work better for my setup, test it.

If you running room temp and pellets are falling off the end of the pot reduce your feed about a half point, keep droping it back till your about an inch from the edge of the pot. Using the short end plate and no stirrer may reduce the blown around ash too, let it fall straight to the pan.

I have 4 years on a pc45 burning pellets, i have no damage to the burn pot like you describe. I had experimented with the stirrer and it isn't helpful for pellets.

There had been a thread about the harman pb105 furnace cracking the burn pot, the factory fixed that by adding ribs across the bottom of the pot, i guess it helped absorbe some of the heat and the steel didn't deterioate.

Then your combustion flame isn't O2 positive. If it was, your start eating ferrous parts in direct contact with the flame. That applies to corn and pellets, fuel don't matter. What matters is oxygen content. If I was the guy of Flea Bay selling stirrer/agitator rods, I'd tell everyone to run a 'blowtorch' flame and sell a pile of stirrers (and burn pots too).

In actuality, a blow torch flame transfers less heat to the HX (or in BB's case HX and Crosslink) than a moderate (somewhat lazy but not agressive flame) because the dwell time for the heat trabsfer is less with the agressive flame. You keep the venting hot, thats about it.

My 6039-41 (which is basically a Magnum Countryside copied by USSC has enough built into the control board settings (user accessable so long as you know how to access them) to control the air/fuel mixture exactly the way I want it. Your stove may be different..

I've been playing with this stuff for over 30 years and thats no bs. I started way back when Dove Tek and England Stove were the only 2 manufacturers that produced space heaters that were widely available and venting was limited to Simpson and Selkirk and not all that much variety wise either.

They have come a long way but the principles of combustion remain the same.

 

[SidecarFlip]

I have been trying to make most of my replies to the thread applicable to the OP who burns only pellets. The PC45 is a bit quirky. I have used three different ages of CB and all burn a bit different. If I hadn't had to buy a new board this season I would have bought a DDM and would be able to get more info on its settings and configurations. Might be the reason Harman decided to stop manufacture as the many options caused to many headaches when owners don't use the accessories as the manufacture states. Easier to just mount a pot, install one exhaust plate, and one set of dip switch settings, and get out of the dedicated multifuel with its set of headaches of how dry and how many chunks etc.

Far as I'm concerned you are doing a good job, as usual.