Pellet Furnace with Backup Propane Furnace?

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Solarius99

New Member
Feb 10, 2012
4
Southern NH
So I've been hemming and hawing on this for about 2 years now... watching my buddy who put in a Pellet Stove saving money on heating and keeping his house warmer.

My situation is such... I have a 3 year old house that is well constructed. Due to lack of access to any other heating fuel besides Oil... I opted for Propane. I hate Oil. Smelly, nasty, big tank, etc. Propane nice and clean (and works for my water heater and kitchen stove) but horrendously expensive compared to all other heating out there.

So I've been wondering... is it possible to take an existing Forced Air Propane Furnace and tie in a Forced Air Pellet Furnace so that the two can be run on the same ducting? This would be to run the Pellet furnace all the time, with the Propane furnace set to kick in as backup in the even the pellets run out or something.

If it's possible... any idea on approximate costs (rough, I understand no one has perfect numbers) for the unit and installation? Any recommendations on installers in Southern NH?

Lastly, any considerations I should be thinking about here that I might be missing?

Thank you!
Shane
 
It's possible, but the first thing to do is to price out fuel in your area. These are regional variances, so what makes sense for one area could be an economic disaster in another. Case in point. Locally propane is over $4/gal., yet pellets can be bought in quantity for a reasonable price. The next question to answer is size. How large an area are you heating? Do you know the input/output btus for your propane system?

Just for rough figures, Harman makes a pellet furnace for about $5200, but it may be oversized if your house is well insulated and sealed and under 2500 sq ft.
http://www.harmanstoves.com/Products/PF100-Pellet-Furnace.aspx
Here's another that sells for about $3200:
http://www.americanenergysystems.com/flex-fuel-furnaces.cfm

You'll need setup parallel connections to connect it to the existing system, but this can be done. It will need isolation dampers to run it in tandem with the propane furnace.
 
The PF100 is an awesome unit but the turn key price can be around $7000 depending on install, venting, and unit. I would look at a freestander as supplement to the LP furnace.

Eric
 
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I did the fuel price calculations on a quickie btu comparison and pellets are nearly half the cost. I factored my current furnace at 90 efficient and the st croix furnace at 81. I think roi would be about 5 years or so if it would be roughly 7k soup to nuts. I will do a more detailed run again. I have about 2400 sq ft to heat and since I work from home I keep it at 69 all day and night (lowest I can handle). Would love to go warmer though where I don't need a sweater in the house. Is the best bet to call my local pellet stove retailer to get installer recommendations?

Oh and the standalone stove didn't really work in my house. No real space for it and the upstairs has a closed stairwell with little airflow going up from first floor. And everything sleeps with their doors closed at night. Oh and the biggest factor, the wife doesn't want to see it. :D
 
kinsmanstoves said:
The PF100 is an awesome unit but the turn key price can be around $7000 depending on install, venting, and unit. I would look at a freestander as supplement to the LP furnace.

Eric
Click to expand...
I absolutely agree with Eric. I have a PF100 and have run it for now this is my 2nd season. The thing is a tank! They may be a little pricey but well worth it in the long run. They are very easy to tie in to your existing system just the matter of a couple dampers and a little duct. There are a few of us on here.

Farenheit makes a furnace as well that can be tied in. The are few of those folks running around here too.

I know there are a few others I know hossthehermit has something different and it works well.

No matter what they are a great investment. Last year I saved 1/3 my cost in oil and this year is a little over 1/2 my cost of oil. So this year if I were to burn $1000 of oil it would cost me just under $500.

All and all it can be done with whatever Furnace you may pick
 
Wow... that PF100 is a mighty beast... and has a price tag to go with it. Looked up my furnace model now that I am home... its a Concord Air Furnace that has 80k BTU input... 76k BTU output.... 95% efficient. Is the PF100 overkill with it's 112k BTU rating? And looking at the Farenheit, it has a 50k BTU rating...

My experience with heating is the same as my experience with warp drives... nil. :)
 
Solarius99 said:
Wow... that PF100 is a mighty beast... and has a price tag to go with it. Looked up my furnace model now that I am home... its a Concord Air Furnace that has 80k BTU input... 76k BTU output.... 95% efficient. Is the PF100 overkill with it's 112k BTU rating? And looking at the Farenheit, it has a 50k BTU rating...

My experience with heating is the same as my experience with warp drives... nil. :)
Click to expand...
I can tell you my oil furnace is rated very similar to your propane but it was only about 82% efficient. My house is 1400 sf and about 9 years old, and built/insulated to Canadian standards. With my "cold" nights of the last few days of about 0 to -10 my furnace does run all night. Now I will tell that it is the maintainence fire and I do keep my house at 74 degrees all the time for the wife and kids. I burn between 3 & 4 tons a heating season and no oil.

I did look at the Farenheit myself the lower btu kinda had me a little nervous and when I spoke to the dealer he said it might keep up with my heating needs. The Farenheit does have an auto clean where the ash is dumped by an bulldozer action through the bottom of the firepot. This did make me a little concerned as well. I have heard of a few stories about the auto clean on any pellet stove or furnace getting jammed with a clinker and not running. The Harman has an open end fire pot meaning that the burning pellets push the ash out of the way and into the ash pan.
 
I run a Fahrenheit and although my Wood eater is 15' away, I have had it on level 1'(manual) with feed and air trims at 5, and the house has been between 74* (day) and 69* (night). I have a 2,180 sq ft Ranch and the furnace is in the basement and in an 800 sq ft area.

It's only rated at 50,000 BTU, but its pretty efficient. IMO. Also, the auto clean on it, is attached to two Huge actuators. Trying to stop one of them from moving would be pretty hard. Even with a MASIVE clinker and a malfunction of some sort.

They are cheaper and have a smaller distribution blower, but I only have half my house ducted to it. The other half is cut off (manual damper that's shut).

Anyways. Welcome... Keep looking on the used Market. A member here just picked up a Fahrenheit for $1,000 with some duct work, venting, and hopper extension. That's dirt cheap!!

(Edit: Pic added)
2012-12-10_20-00-47_521.jpg
 
I'm digging that Harmon forced water system adapted into a forced air furnace system. Especially with the water heating capability and that I could place it alongside my existing furnace and further away. I will have to look into that option... plus if I ever finish my basement I can run baseboard heating for the finished room instead of trying to run additional ducting. Thank you for that... now to find an installer that could do that. :)
 
hydroflex has a peak output of 60K Btu....you'd be pushing it, and its significantly more "hands on" than the PF100 with a pretty similar pricetag. Keep in mind that the PF100 by Harman is variable on it output, so you are not "subjected" to the machine. It can go as low as about 9K BTU and up to the 112K.
I like the PF100 a lots. Its pretty straight forward and not a bear to clean if you are even remotely diligent.
 
Been running a PF100 pellet furnace for about 4.5 years with a parallel oil furnace. Nice even heat. Holds 4 bags of pellets. Only need to empty the ash pan once a year. Duct registers enable individual heat control to each room. More work than a gas furnace but the financial return makes it worth it for me.

Be sure to check the reputation of the dealer very carefully and know you can depend on him for future warranty work. This forum is a weath of information and great guys willing to help; so you can check here and see if what the dealer is telling you is good.
 
Another option is the Harman PB-105 boiler, this would be large enough to meet your needs at the present time including DHW usage plus the fact it still will be large enough if you decide to finish the basement using baseboard heating. The PB-105 is going to cost a bit more to purchase than the PF-100 but with the DHW coil you will be able to get all the hot water you need. I don't know what size coil you will need for your duct work but the link gives you an idea of what they cost.

http://www.pexuniverse.com/brazetek-17x21-water-to-air-finned-coil-heat-exchanger
 
Yesterday I finally got the PF-100 installed and running. In my first day of operation I seem to be going through a lot of pellets, 3+ bags. My house is a 2-story Colonial and is 22 years old. I normally would burn about 1,000 gals of oil/year and kept it at 68/9 degrees. Is amount of usage normal? At this rate I will burn 10 tons of pellets/year.
 
Takes a while to get everything figured out and dialed in.
How many square feet is your colonial?
Do you have insulation, insulated windows and good caulking?
Did you hook up outside air (OAK)?
Did you install isolation dampers at the hot air output ducts of your furnaces? (Assuming you kept the propane furnace)
 
Ah, I forgot some of the details. The house is about 2,100 sqr ft. There is insulation, therm-o-pane windows and caulking from the outside when I painted the house last year. I did have outside air hooked up 4" pipe. Yes there are 3 isolation dampers installed in the system. Yes I kept the "oil-fired furnace". Thanks for your reply.
 
I see your current temperature ranges from the 20s to 40s. Are you are still running your house temp at 68/9 and do you turn it down at night or keep it at the same temp?

Why do you need 3 isolation dampers and where are they located in your ductwork?

I have about the same situation as you except my place has relativly new insulated windows but poor insulation. My lowest outside temps range between the 30s & 40s then I burn about 2.5 to 3 bags a day. I run my place at 70 but turn it down to 64 overnight. I use between 6 & 7 tons a year.
 
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3 bags/day in the coldest months seems ok to me. I'd guesstimate you to burn somewhere's between 7-8 tons based on your 1000 gal/ year oil use.
 
even at 10 tons a year and cost of 300 a ton which is high that is only $3000.00 for the pellets and 1000 gallons of oil I paid 4.10 a gallon is $4100.00 thats over a $1000.00 savings and i am sure you will be able to lower your usage with experience good luck. and enjoy the savings and warmth
 
Are there settings that I should check/change than might make it run more efficient? I have read about changing the ESP setting from the factory supplied setting. I'm not sure what the ESP is.
 
exoilburner,

I have one damper to close off the return air from the oil furnace and two others to close off the pellet furnace if I need to go back and use the oil furnace. So running the PF I have one one damper closed and two open.

I have the temp set for 69 and run it 24/7. I have a setback thermometer for the oil furnace. I guess I should try turning down at night and during the day when I'm not home.
 
Fahsha said:
exoilburner,

I have one damper to close off the return air from the oil furnace and two others to close off the pellet furnace if I need to go back and use the oil furnace. So running the PF I have one one damper closed and two open.

I have the temp set for 69 and run it 24/7. I have a setback thermometer for the oil furnace. I guess I should try turning down at night and during the day when I'm not home.
Click to expand...

I am not an HVAC expert and was wondering why a third isolation damper.

Check out what the PF100 Install Manual says:( http://hearthnhome.com/downloads/installManuals/PF100.pdf ).

Installing Duct
The pellet furnace may be connected to a gas or oilfired
central furnace or heat pump duct system. Prior
to installation, determine whether all requirements for
installation including all clearnaces can be met.
The pellet furnace warm air supply and the cold air
return must be installed in a parallel arrangement.
EXAMPLE: The warm air supply duct from the pellet
furnace is to be connected to the warm air supply of the
existing furnace. Also the cold air return duct from the
existing furnace is to be connected to the cold air return
duct of the pellet furnace. Isolation dampers (2) should
be installed in the ductwork. (1) in the warm air supply
duct for the existing furnace and (1) in the warm air
supply duct of the pellet furnace after or “downstream”
of the high limit/fan control. These dampers can be
manually operated or fully automatic. In either case,
the unit that is not being used must be prevented from
being operated. (This also can be done manually or
automatically.) NOTE: Any control wiring, power wiring
needed should be performed by a qualified installer
and/or electrician.
The warm-air supply outlet of the pellet furnace shall not
be connected to the cold-air return inlet of the existing
furnace because of the possibility of overheating
components of the existing furnace, causing the existing
furnace to operate other than as intended.
 
The HVAC people set it up to one damper when the PF is operational. The one stops all air flow going through the oil fired furnace. The two other dampers close off the PF when the oil fired furnace is operational. I guess this setup was used due to the current layout of my ductwork.

There seems to be quite a glow coming from the PF even if the blower motor is not cycling on/off. Is this normal? It seems like it is burning a lot of pellets and the heat is going up the flue.
 
Fahsha

Why not start a new thread instead of hijacking the OP's thread? Also, why are you not contacting and having the people you bought the unit from come fix it, or teach you how to use it?

That is what I get for service, even after four years!
 
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