Harman pellet stoves function in some fundamentally different ways than just about any other pellet stove on the market. I am of the opinion that Harman makes the best pellet stove on the market, and the P series represents the best of Harman pellet stoves. This review will hopefully explain how I arrived at that conclusion.
Lets start with what all Harman's have in common-
Pellet Pro system
The first thing is what they call the Pellet pro system. This and one other thing are what makes a Harman a Harman.
|Early Harman Pellet Pro model|
Harman's have "ESP"
The second thing that really sets Harman stoves apart is the use of what they call and ESP probe. Now some of you might hear ESP probe and think it is a device used on ghost hunters, but that is not the case. The ESP (Exhaust Sensing Probe) basically measures the temperature of the exhaust and regulates the feed rate based on the exhaust. By knowing the exhaust temperature you can extrapolate the heat output of the stove.
When you turn most stoves to a particular setting you are basically controlling the feed rate, and that rate is a fixed amount of auger rotation over a fixed amount of time. So the same setting on a most stoves can equal rather different different stove heat outputs based variations in pellets, and as you know from this site there can be some real significant variations in pellets.
By contrast Harman stove temperature settings 1-7 reflect a paticular exhaust output temperature and will automatically adjust the feed rate to maintain a consistent output at the given setting. This system works extremely well, and harman has been perfecting it for over a decade now, so it is a very mature system.
Stove Temp versus Room Temp
The other common feature to all Harman pellet stoves is the room temperature sensor. It is basically the temperature probe for the onboard thermostat. So you can essentially set a room temperature and the stove will keep it there by raising and lowering the fire, and if it does not call for heat over an extended period the stove will shut off, and then relight when heat is called for again (with the exception of the P38+).
Here is where I offer a couple criticisms about the Harman system. It is difficult (not impossible) to hook in a programable thermostat to the stove. The second is that running a Harman in room temperature mode is not nearly as efficient as stove temperature mode. I always run my stoves in stove temperature mode, and they work great.
Things specific to the P series
|P series with nickel options|
These are just one of the most simple stoves to completely clean. Basically open the door, scrape the burn pot out, scrape the accordion heat exchange (common to P series), brush the ash down into the ash bin, open the bottom door and pull out the ash bin (which is huge btw), pull off the exhaust fan cover and clean and vac out that area (be care around the ESP), and done.
One you are experienced this whole process should take 20 minutes if you take your time. About one a year you should also remove the door to the feed system and vac it out. This requires removing one of the lower baffles.
These are all very simple tasks compared to other stoves.
One interesting thing Harmon does is that the housing for the combustion fan is part of the stove, and it is offset in such a way that you can see straight out of the exhaust.
I realize this is sorta inside baseball stuff, but if you are a DYI type it makes ownership of the stove a much more pleasant proposition.
Differences in the P series
Pellet Hopper Capacity
The P series has generally above average hopper capacity. Essentially the P series has 3 frame sizes- small (P38 and P43- 50 LBS), medium (P61 and PC45- 72 LBS), and large (P68- 76 LBS). All these can be increased with a sinfully ugly hopper extension, but if you are burning these in a basement the hopper extension might be just the thing you need. They typically add about 50 LBS of capacity, and is a feature unique to all the P series stoves.
This is an area where Harman pellet stoves shine in general, and the P series in particular (even the P38 is pretty strong. I have heard it said that Harman pellet stoves put out heat like a wood stove, and it is true. As I mentioned before I have owned a number of other pellet stoves, and none of them put the real world heat out like Harman.
The P series in particular give you a considerable amount of radiant heat in the room they are in. Most other pellet stoves do not put out much in the way of radiant heat at all.
Differences within the P series.
The first thing to note is the number after the P in the model indicates the maximum BTU input to the stove in thousands. For example a P61 has a maximum BTU input of 61,000 BTUs.
P38+ versus P43
These are pretty much the same stoves, but the P43 has auto light. In terms of the difference in 5,000 BTUs between the models, I suspect there is a very minor real world difference between the stoves.
P61 versus PC45
These stove are the same frame size, but there is a huge difference in the burn pots. The p61 is s pellet stove, the PC45 is a pretty much anything palletized stove. The PC45 comes with an additional burn pot, and 2 different agitators that connect to the end of the auger to stirs fuels like corn that want to clinker very quickly. There is also a series of dip switches that need to be set differently for different fuel types. I currently burn a PC45 set up for pellets, and it seems to have a similar heat output as my P61 did.
P61 versus P68
The P68 is a minor increase from the P61. The dimensions of the stove are nearly identical, with the P68 being 2" taller, and holding 4 more pounds of pellets. The burn pot is a bit larger as well. If you are trying to heat a large space this is your stove. This stove will put out more than many wood stoves, and was the highest output free standing pellet stove on the market.
As you can tell I am a fan of these stoves. My recommendation of the P series stoves in the P61. It is powerful enough for most applications and just does almost everything well. I have found the loner I owned a Harman the more I liked.
Eventually I would like to get a XXV as it blends the great functionality of the P series with the great looks of a classic cast iron stove. I look forward to writing that review.