Opinions on Harman PF100 Pellet Furnace?
- Thread starter GS7
- Start date
-
Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.
We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.
We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil. -
Super Cedar firestarters 30% discount Use code Hearth2024 Click here
- Status
Did you replace it with something else? I'm leaning towards a kuuma vf100. Gotta find a good hvac guy in New Haven area of CT
I sold the house. In my new house I went with a Pellergy system that hooks up to a Buderus 4 section boiler.
Downeast Farmer
Member
- Jan 20, 2013
- 69
I have no first hand experience with the unit you specifically named but I have had ton's of experience with wood/pellet furnaces in general. I'll offer my comments regarding wood and pellet furnaces as a group.
The fundamental difference between a furnace and a boiler is that once that call for heat has ended, there is absolutely no place for the heat to go except into the steel of the unit itself. This is a matter of simple physics being that air is a poor "absorber" of heat. If you would measure the amount of "heat" a cubic foot of air can hold, compared to the same volume of water, you will find it is a but a small fraction given the same temperature rise.
So once the pellet or wood furnace is burning merrily away and providing heat it has to go somewhere or meltdown occurs at some point in the unit. Don't let anyone kid you and say it is not a problem or that it is no big deal. I've seen dozens of them over the years that are warped, twisted, cracked and sometimes just burned through because there is no "storage" capacity with air. Once the blower shuts off there is no possible way to extinguish the flame instantly so the heat just builds.
Blower off delays help to an extent but even if it runs for several minutes after the damper closes or the draft blower shuts down, there is still heat being generated in the firebox. There is no surefire way drop the heat output to zero without having to rekindle a fire each time you need heat. Some companies have dealt with the problem by having the blower run continuously but that adds its own set of problems with dropping the flue temp too low, reducing comfort levels in the heated space and also increased energy consumption.
I will grant you that a pellet furnace deals with this on a little better level than a wood furnace because the volume of fuel in the firebox is obviously far less. A pellet furnace can shut down far more quickly than a wood furnace but the flip side of that start stop ability is exactly that. Starting and stopping which decreases equipment and component life and adds stress to the metal due to constant heat cool cycles. It is still a problem that has to be dealt with.
Not trying to throw water on your fire (pun intended) just want you to know there are issues inherent to the type of equipment regardless of brand. At some point you will always face the result of those issues and compromises.
The fundamental difference between a furnace and a boiler is that once that call for heat has ended, there is absolutely no place for the heat to go except into the steel of the unit itself. This is a matter of simple physics being that air is a poor "absorber" of heat. If you would measure the amount of "heat" a cubic foot of air can hold, compared to the same volume of water, you will find it is a but a small fraction given the same temperature rise.
So once the pellet or wood furnace is burning merrily away and providing heat it has to go somewhere or meltdown occurs at some point in the unit. Don't let anyone kid you and say it is not a problem or that it is no big deal. I've seen dozens of them over the years that are warped, twisted, cracked and sometimes just burned through because there is no "storage" capacity with air. Once the blower shuts off there is no possible way to extinguish the flame instantly so the heat just builds.
Blower off delays help to an extent but even if it runs for several minutes after the damper closes or the draft blower shuts down, there is still heat being generated in the firebox. There is no surefire way drop the heat output to zero without having to rekindle a fire each time you need heat. Some companies have dealt with the problem by having the blower run continuously but that adds its own set of problems with dropping the flue temp too low, reducing comfort levels in the heated space and also increased energy consumption.
I will grant you that a pellet furnace deals with this on a little better level than a wood furnace because the volume of fuel in the firebox is obviously far less. A pellet furnace can shut down far more quickly than a wood furnace but the flip side of that start stop ability is exactly that. Starting and stopping which decreases equipment and component life and adds stress to the metal due to constant heat cool cycles. It is still a problem that has to be dealt with.
Not trying to throw water on your fire (pun intended) just want you to know there are issues inherent to the type of equipment regardless of brand. At some point you will always face the result of those issues and compromises.
BoilerMan
Minister of Fire
What about a wood stove? It is my understanding a wood furnace is basically an EPA stove in a sheetmetal box. Correct me if I'm wrong here, a good part of my family heats with wood furnaces that are quite old, good ducting should have some convection to cool the firebox in the event of power outage.
TS
Very true Taylor. Just look at all the ancient wood coal gravity furnaces that were used decades ago. Their operators knew how to fire them according to the weather. (Neadertal man outdoor reset?)
Knew that they had to have dry wood put up a couple years in advance. And the duct was sized to allow heating by convective air flow only. THAT is the key difference between a "modern" wood furnace and the old girls out there. There are more than a few in basements around these parts yet to this day. Some of which are crowding 70-80 years old.
A couple other "minor details"........the working surfaces were cast iron, often lined with brick and they weighed about 1500 pounds. Far different beastie than a modern wood/pellet furnace.
About like making a construction comparison between a Ketel-One and a Windhager pellet boiler. There is none.
I like the Pellergy better. I've got a 5 ton bag bin so I don't have to feed it every day and it's easier to clean thoroughly than the Harman. It also ignites much faster than the Harman.
BoilerMan
Minister of Fire
My BIL has a Lennox that is exactly as you describe. He, and the rest of my family do not know how to operate wood appliances though and it makes a TON of creosote............trust me, I've helped him clean their chimney. They simply do not believe me about proper seasoning and burn practices, and I only brush the flue once a year just to get the flyash out for summer corrosion.........Ah well.
TS
- Status
Similar threads
