The Harman PB105 - Tell me about it

[DBNH22]

I am in the process of doing a great amount of reasearch into alternative heating solutions as I currently have an oil boiler and am tired of paying high oil costs in New Hampshire.

I looked into many different sources and here's what I have found.

natural gas: not readily available in my area

coal boiler: coal not readily available or affordable in NH

wood boiler: wood prices can be volatile here in NH

wood/pellet stove: i want something that radiates heat. something I can tie into my existing baseboards

geothermal: my last name isn't Gates or Buffet so these are both out of the question


It seems like the pellet boiler is the best choice for what I'm looing for and I'm seriously considering purchasing a PB105 prior to the next heating season.


I'm aware of the burnpot issue.

Is there anything you guys can tell me prior to buying one? HOw much have you saved? How much maintenance is involved? Any tips/tricks to getting the unit to operate most effectively? Anything at all that those of you who have expereince with this unit can share with me would be most appreciated.

Thanks

 

[sinnian]

You should check out the Pinnacle PB150 too ~ click the link in my signature. Mark is the NE dealer, great guy and it doesn't cost anything to talk.

 

[SmokeEater]

I am in the process of doing a great amount of reasearch into alternative heating solutions as I currently have an oil boiler and am tired of paying high oil costs in New Hampshire.

I looked into many different sources and here's what I have found.

............................................................................................ much maintebe most appreciated.

Thanks

Dana B, I bought and installed a PB 105 over a year ago and have to date burned over 12 ton of pellets. The boiler has operated flawlessly and I've had no problems with the burn pot issue. Mine has the older igniter and not the pressure igniter, but it has operated well. I have a 100 gallon indirect water tank that doubles as a buffer for the 105 so all the 105 does is keep the buffer up to temp and that is set on the boiler's control panel. I run at the max of 185* F. I don't have the OAT sensor connected and I operate the pellet feed at the 4 setting without change. The stack temp about 6 or 7 feet from the combustion fan never goes above 175* F read on a magnetic surface mount guage. Not very accurate, but in the ball park. For each ton of pellets burned I empty the ash pan and that could be each 20 to 30 days. I will reduce my burn this year by almost 1/3 because I'm insulating my floor joists on the main floor and turning 1/3 of my heated space to a lower temperature (78* F to 50*F). The 105 has lowered my heating costs to 1/2 of what they were with oil. I have a Liberty Slantfin 130,000 Btu oil boiler that is also connected to the buffer to pick up if we are away or if the pellet boiler runs out of fuel. It has only on a few occasions. I let the boiler run out of pellets on the weekend and open it to clean the burnpot and the sight window. The whole process takes about 10 minutes, 15 if you need to empty the ash pan which holds about 10 pounds of ashes, all you get from a ton of pellets. It doesn't have a self cleaning burn pot and it needs a little maintenance, but for the $$, it's robust and reliable. Puts out lots of Btus for the buck.

 

[ScotL]

I installed my PB105 in 2008 - the only year I could have done it and missed out on the tax rebate.
I had it's water lines connected right into the loop for my oil boiler. I run it all year, except if I'm away on vacation. In the summer it's only heating my domestic hot water so I turn down the high and low temperature settings.
I have not had the burnpot problem the PB105s are known for. When it was first installed it had trouble with the water temperature sensor and they replaced the sensor, control board, and changed the ESP to the red wire thermocouple. None of that fixed it. It was shutting off too soon. I fixed it myself by pulling the sensor up a little so it wasn't sitting right in the bottom of the well - about 1/2 way up.
I've replaced the ignitor once under warranty too. It's the old style ignitor. My original had 11 fins and the replacement has 13.

I do the same thing as SmokeEater for cleaning. I let it run out on the weekend then swing the front open and scrape it out. I've learned that it's really important to clean out underneath the burnpot every time too. I also give the guard under the ignitor and the edge of the burnpot a few taps with the scraper. Ash can collect in the ignitor and it won't ignite the pellets. After letting it run empty and cleaning, I put a handful of pellets in the burnpot before restarting because the auger is empty (since I let it run out).

Every day I refill the hopper and pull the cleaning rods a few times each. About twice per year I stick the leaf blower on the exhaust and suck out the dust and brush out the piping.

One thing I've noticed that I don't like is the outside air adapter. The way the front swings out on hinges is excellent for cleaning. But, it's very difficult to attach an outside air kit to it. I wouldn't have bothered trying to install one, but if you skip cleanings or let ash build up around the ignitor, it can backfire. It will take so long to ignite that a lot of pellets build up in the burnpot and then a lot of wood gas builds up in the burn chamber before it ignites. It will fill with smoke then ignite all at once with a big BOOM. When that happens, smoke blows back out through the air intake and, without an outside air kit, into your house.

 

[Mr._Graybeard]

Another PB105 owner here. This is my first heating season with the boiler, and it looks like I'll end up burning between 5 and 6 tons of pellets to comfortably heat my unevenly insulated 2300-square foot farmhouse. My 28-year-old Burnham boiler probably would have gone through 800 gallons of heating oil this winter, with room temps 3 or four degrees cooler.

As Jimmy and Scot said, maintenance has been pretty much a breeze. Scrape the burnpot every few days, empty the ashes maybe once a month. There is a trap for the pellet sawdust (fines) that needs cleaning -- I empty it every week or two. I've had the combustion fan off a few times for cleaning, usually when emptying the ashes, and I've vacuumed out the flue using a leaf blower. Mostly I was looking for something to do ...

My burnpot developed a bulge within a month after I started burning, and it now has a couple cracks. I'll have it replaced this spring.

I notice that others talk about running the boiler feed on 4 -- I usually have it at 3. The flames look a little rich to me at the higher feed, but maybe the leaner burn is too hot for the steel in the burnpot. I'm sure I'll be fully debriefed by my dealer when he makes the warranty repair!

I don't have a lot of options for boilers in Wisconsin if I want a local dealer. All in all, though, I'm very happy. The Harman isn't as high tech as some competitors, but it's market tested since 2006. The company seems to have used that testing to make a better product.

 

[katman]

Installed my PB 105 last March in my barn and ran about 100 foot underground thermapex to the house. I have the same experrience as smokeeater. I bought an inventory unit that has an upgraded (13 fin I think) ignitor but doesn't have the new pressure ignition system. Works fine for me with no burnpot issues and keeps my house (about 3,000 sq ft with 30'foot cathederal ceiling in main room) very comfortable (wife loves the heat at 70 degrees). Should end the season with about 6-7 tons burned, about 1/3 of the cost I would have spent for heating oil/propane. Zero problems. Only issue for me is I want to get a bulk hopper so I don't have to run backup heat (heat pumps or oil) when I am away for several days! There are other pellet boilers out there so look at the options but you won't regret switching to pellet heat.

 

[iceguy4]

Dana B, I bought and installed a PB 105 over a year ago and have to date burned over 12 ton of pellets. The boiler has operated flawlessly and I've had no problems with the burn pot issue

As Jimmy and Scot said, maintenance has been pretty much a breeze. Scrape the burnpot every few days, empty the ashes maybe once a month. There is a trap for the pellet sawdust (fines) that needs cleaning -- I empty it every week or two. I've had the combustion fan off a few times for cleaning, usually when emptying the ashes, and I've vacuumed out the flue

X2

 

[katman]

Ice keeps reminding us he got the bulk storage, too! That's the way to go.

 

[Mr._Graybeard]

Not to hijack this thread, but as long as it came up, perhaps one of you guys can explain to me the benefit of having bulk storage in a pellet-fired system. I can certainly understand its place with a woodburner with its relative lack of fuel control, but the pellet boiler system is not like that -- it's burning full bore from ignition to the point where the thermostat shuts down fuel and the fire burns out. Yes, ignition produces a brief period of inefficient burning, but keeping an 80-gallon buffer tank warm presents its own inefficiencies, IMO. And in the heart of the heating system this year, my boiler fan was running pretty much nonstop and at least a small fire was going most of the time (so cold ignition was relatively rare).

Not to shoot down anybody's methods -- we all have our own ways of doing things.

 

[velvetfoot]

I think it's bulk storage of pellets, no?

 

[ScotL]

So you don't have to fill it so often. Or, you won't have to fill it at all if you buy bulk delivery. That would be the ideal use of a bulk hopper. It's becoming more common.
My new boiler, the Kedel, doesn't always run full bore. It's able to throttle to 15% of it's capacity without much effect on efficiency. They key to that is the oxygen sensor and the PID loop controller.
I can also manually throttle back my Harman boiler, like I do in the summer, by reducing the low and high water temperature settings as low as possible. My hot water doesn't have to be any warmer than 120° so I turn the boiler down to a max temperature of about 150°.

 

[Mr._Graybeard]

I have a 100 gallon indirect water tank that doubles as a buffer for the 105

This is water storage, not pellet. That's what I'm referring to. On reflection, I imagine a reserve of heated water can help a boiler "punch above its weight" while heating a large space, like 4k square feet or more.

I'll be interested to find out how the Kedel does its burn, Scot. The Harman basically burns all the fuel it's fed as fast as it can -- the control is in the fuel feed, as there's no damper to control air.

 

[iceguy4]

Not to hijack this thread, but as long as it came up, perhaps one of you guys can explain to me the benefit of having bulk storage in a pellet-fired system. I can certainly understand its place with a woodburner with its relative lack of fuel control, but the pellet boiler system is not like that -- it's burning full bore from ignition to the point where the thermostat shuts down fuel and the fire burns out. Yes, ignition produces a brief period of inefficient burning, but keeping an 80-gallon buffer tank warm presents its own inefficiencies, IMO. And in the heart of the heating system this year, my boiler fan was running pretty much nonstop and at least a small fire was going most of the time (so cold ignition was relatively rare).

Not to shoot down anybody's methods -- we all have our own ways of doing things.

Bulk storage of pellets 1300+ lbs so you don't hve to attend boiler as often

 

[SmokeEater]

This is water storage, not pellet. That's what I'm referring to. On reflection, I imagine a reserve of heated water can help a boiler "punch above its weight" while heating a large space, like 4k square feet or more.
....................................to control air.

Mr._Graybeard the insulated buffer tank will lose some heat to the surroundings, but that remains in the home and is not really "lost". My purpose in using the 100 gallon buffer was to enable the pellet boiler to fire at a high rate for a longer period thus preventing short cycling. The second, and important, function of the buffer is that it contains potable water and is the source of the DHW for the house. It has an ASSE 1070 thermostatic mixing valve to adjust the DHW to 120*. Another reason for the buffer was to effectively isolate a parallel connected oil fired boiler from the pellet boiler. Either boiler can supply heat to the buffer and so if the pellet boiler is not operating, the oil boiler will take over if the buffer water reaches a preset minimum that is easily adjustable. Another reason to connect both boilers to the buffer is that either can supply DHW at any time of the year, all that either boiler needs to do is to heat the buffer to 185 and that tank of water will supply the house for several days without either boiler running over that period. Lastly, both boilers can supply heat to the buffer simultaneously if ever necessary, inputting over 230,000 Btus per hour to the buffer/DHW tank.

 

[Mr._Graybeard]

Mr._Graybeard the insulated buffer tank will lose some heat to the surroundings, but that remains in the home and is not really "lost". My purpose in using the 100 gallon buffer was to enable the pellet boiler to fire at a high rate for a longer period thus preventing short cycling. The second, and important, function of the buffer is that it contains potable water and is the source of the DHW for the house. It has an ASSE 1070 thermostatic mixing valve to adjust the DHW to 120*. Another reason for the buffer was to effectively isolate a parallel connected oil fired boiler from the pellet boiler. Either boiler can supply heat to the buffer and so if the pellet boiler is not operating, the oil boiler will take over if the buffer water reaches a preset minimum that is easily adjustable. Another reason to connect both boilers to the buffer is that either can supply DHW at any time of the year, all that either boiler needs to do is to heat the buffer to 185 and that tank of water will supply the house for several days without either boiler running over that period. Lastly, both boilers can supply heat to the buffer simultaneously if ever necessary, inputting over 230,000 Btus per hour to the buffer/DHW tank.

Ah, I get it now -- you're getting DHW out of the tank. And either boiler can heat it -- very clever.

I recall a thread where a tech on the board recommended using a storage tank on pellet boilers to retain thermal mass, like a gasifying wood boiler. When you mentioned the tank it came to mind. Sorry for the confusion.

 

[mkhopper]

Check out kedelboilers.com, there is a dealer in portland Me. Also Windhager has a dealer in MA http://www.hydro-to-heat-convertor.com/pelletboilers.html

 

[ScotL]

This is water storage, not pellet. That's what I'm referring to. On reflection, I imagine a reserve of heated water can help a boiler "punch above its weight" while heating a large space, like 4k square feet or more.

I'll be interested to find out how the Kedel does its burn, Scot. The Harman basically burns all the fuel it's fed as fast as it can -- the control is in the fuel feed, as there's no damper to control air.

This seems to adjust feed rate based on the calculated BTU requirement (it ramps up and down it's firing rate from 15% to 100% as needed). Then it adjusts it combustion fan speed based on the oxygen sensor and the required amount of oxygen at that specific firing rate. At 100% power it expects the oxygen content to be lower than at 15% power.

So far, the only thing I don't like about this boiler is the exhaust. Its design does not allow for direct venting. It looks just like an oil boiler chimney, weighted draft flapper and all. You have to have a stack at least 17' tall. Mine is that tall but the building is a slight vacuum so I need to install a draft inducer.

 

[MikeN]

I've had my PB105 since March 2012 (manufactured in 2009/2010). It has taken me a LONG time to really learn how to operate it properly. The manual that Harman provides for it is terrible and doesn't give enough detail on some crucial installation, operation, and maintenance steps. While I love my dealer, they aren't technically proficient on the installation and use of these either. Few people have them installed here in Alaska (and realistically nationwide). I'm a DIY'er, having only installed one oil boiler before installing this system - but even the professionals don't seem to completely understand this system.

This lack of information is really a shame, since it is quite well-designed. Harman is probably losing customers as word gets around that these systems "don't work right". Thank goodness for this board-- or I never would've gotten mine straightened out after it started having problems. That said, I've cut my heating costs in half from oil. I've also saved on my electric bill because my my baseboard circulation don't run as much because there is ample hot water available on stand-by.

If you buy one of these, plan to become an expert, do the maintenance, and tinker with it. Don't expect your dealer or boiler mechanics to understand this system. Read the manual carefully. Learn about common boiler issues such as corrosion, expansion tanks, etc. Some additional hints:

- You need two overheat zones -- a gravity fed loop for a power failure and a second for overheating with power on.

If the boiler overheats while operating, it powers a circuit. Use this circuit to power a circulation pump and open a zone valve for one of your existing heat loops, allowing excess heat to dissipate. The PB105 often overshoots a few degrees (e.g. all your zones stop calling for heat but the system is still burning pellets).

A second unused heat-dump loop is needed for a power outage. It should be fitted with a special zone valve that operates the exact opposite as a normal zone valve. That is, the valve should stay closed when there is power and open when power is lost. This should be tied to the same circuit (and probably transformer) as the rest of your system. That way, if you lose power and there is still a fire burning, this loop opens and can gravity feed to the boiler, dissipating heat. This zone for power-outages should be mounted higher than the boiler.

- Install the PB105 on a dedicated circuit breaker (or switch). It has a computer (control unit) -- and like most computers rebooting is helpful. You'll want to cut power when replacing parts.

- Have parts on hand and learn how to swap them. I've been through one igniter, other users have replaced many. I've replaced an aquastat too.

- No damp or disintegrating pellets. If the hopper empties, look for dust in the bottom that can clog the slide plate. Remove as needed.

- The manual touches on the pressure sensor switch -- but this is a critical component and should not be overridden.

When I first began using the PB105, I missed cleaning the combustion fan -- and as a result, the draft in the burn chamber was gradually lessening, creating a smaller and smaller flame. This also caused problems with the auto-ignition. While the system would still light and burn manually, I realized there was something wrong with the draft. After fiddling with it, I put my hand over the air inlet and noticed how much better the system burned. So, smart me put a piece of tape over a portion of the air inlet. Others on these boards have put socks onto the air inlets. This is a WRONG MOVE! What I was doing was causing the system to route air from other parts of the boiler (through the ash cleanout, etc) rather than the designed flow-path. Once I figured out that my flu was slightly blocked and the fan wasn't moving air, I cleaned it - and voila - the system worked perfectly again without reducing air flow through the air inlet! (BTW, I think my first igniter died due to the lack of airflow).

- Proper cleaning is critical. You need to clean the path from the pellet entrance to the smoke outlet!

The ignition system works by forcing air up through the igniter then through holes in the burn pan and up through the pellets. To keep this working , you need to religiously scrape the burn pan and keep the air holes open. One of the things I like least about this boiler is that, to clean this burn pan properly, you really have to wait for the flames to die down and turn off the system. There is a red knob that you unscrew while trying not to cut your hand on the bare edges of the metal frame. Harman claims you can clean it through the main boiler door (glass door), but I've found this difficult. Using their method, your arms brush on the frame and you get soot on you and the tool they provide doesn't fit inside the chamber. You can, however, scrape it while the system is burning by going through this door -- but you need a putty knife rather than the tool they provided.

You also need to clean ash from around the igniter. There are two thumb screws on the bottom of the burn pan that allow you to remove a small metal plate. Ash will build up around the igniter restricting airflow. You need to carefully remove this ash -- but be careful not to mess up the two small electrical wires in here that power the igniter. Tap on the burn pan to remove any ash caught above the igniter.

As I mentioned earlier, the combustion fan area at the back of the boiler is a key area that has to be cleaned. This is located where the exhaust exits the burn chamber before entering the chimney. First, you unlatch two pressure latches, removing the cover. Have something to catch soot in place (I use an old pan). Then, undo the screws holding the fan, accessing the bottom of the chimney. Using a soft brush to clean away all of the soot in the chamber, on the fan blades, and on the fan's frame. If you have an ash vacuum, vacuum the interior of this compartment out well and get as much soot out as you can. Be careful of the ESP probe and make sure to clean it too so that it is properly measure exhaust gas temperatures. You can also brush out the chimney while you have this open.

- The temperature/pressure gauge provided with the boiler and the temperature controls don't agree. If I set my high water temperature to 155 as a high, I get 170 according to the temperature gauge on top of the boiler. This seems to be common.

- The PB105 needs a much larger expansion tank that oil-fired systems. I reused my old expansion tank from my oil system -- and found that the boiler was constantly belching water as a result of being overpressure - which required that I add water. This is VERY BAD. You never want to add waster to a system as it adds oxygen and will rust your boiler out. I replaced my expansion tank with one 5 times larger.

- There is a small temperature probe that sits in an aquastat well located on top of the boiler. This feeds data to the boiler's computer which controls all operations. If the aquastat is not situated tightly in the bottom of and against the well , it will misread the temperature (too low) -- and cause overheating. Expansion/contraction may cause the probe to move over time.

Harman's solution is a 1-inch coiled spring (that you somehow magically must slide over the probe) and a small plug, secured by set screws, to hold it all in place. After damaging my first probe, I ditched this wire spring and instead used a small shim of copper wire. Others have used non-hardening heat transfer paste (though this is controversial as it may harden).

 

[ScotL]

I've had similar problems with the aquastat in my PB105 too. Mine was the opposite though. I had to pull mine up away from the bottom a little because it was always reading too high and the boiler shut off way too soon.