USSC 8500 WON'T PRODUCE ANY HEAT

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Jabbers

Member
Oct 15, 2008
98
NE OHIO
I've seen this exact question asked with no answers. I have a ussc that I just installed. Vent pipe is 4 clean out tee verticle into a 8 inch double wall insulated 16 foot chimney. I know it's not by the book but my chimney isn't to much for my stove I don't think. I have no colored smoke coming out of the stack and my stove seems to draft well. I set my lower lbs per hour down to 2 which is higher than most and the upper set at 6 lbs. I've been up to 3 manual and auto and no heat. The auto draft works better than manual. How do these people get there stove to burn at low lbs per hour and get some heat.I get cold air, my exaust at stove is like 100f and my door is like 19pf and the air coming out at the plenum is 82 f.
 
Are you burning pellets? Does the flame look good? What are your default settings for the Draft Fan (DF) ? Are you just blowing air out of the stove or is it hooked up to another furnace system?

The manual is showing a low feed rate of 5pph, you have yours down to 2pph. You will have to adjust the DF setting as you adjust the feed rates until you have a good burn and heat from the furnace is my guess.
 
I'm burning pellets, flame looks good. I've had draft fan all the way up and it's to much draft plus I've played with the manual draft and I have plenty of draft. I have a smaller house so hopping to use less pellets. I've watched several videos that show you get the low end dialled in then your top end. I don't have plenum hooked up yet thought it would be good to troubleshoot with out. I've watched land air mechanical videos and he seems to know alot about these. I've successfully ran a ussc 5500 pellet stove for years and have it dialed in good so I have some experience. I guess my next step today is measuring my pounds per hour usage to see what I get. When I got in to my stove the low lbs per hour was almost 8 and the hight was almost 15. Successful users use roughly 2lbs on the low and 6 on the high.

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I've seen those videos, while they are fine I've never seen him broach the DF adjustment on the 4 button board. He shows how to adjust the pph feed rates for Pr low and high, or Cr.

My point is that while you've adjusted your feed rate to 2pph, the board DF setting is still set for the higher rate that the board was set for from the factory. You need to adjust that DF setting down or you are just blowing heat out of the exhaust.

To find your default DF settings push the DF low and AUX down at the same time. That will show you the low default DF setting. That's the one you will want to move down until you get heat out of the stove. You can go down as far as you want until the flame starts to look bad or the fire goes out from pellets building up, that would be not enough air.
 
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Ok the first thing I did was reset the furnace to factory settings. The second thing is set my high and low lbs per hour. I then measured my pounds per hour and they were almost dead on. Started up the stove and I have heat. My problem now is dialling in high and low burn setting . Everytime I start the stove I get something different out of the heat output. So I'm gonna wait longer and they suggest running it on heat setting 3 for a few mins before dropping down to 1. We will see how it goes. I've played with the df and it seems to run better on auto plus I want to hook up thermostat so I need to run it on auto.

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Ok the first thing I did was reset the furnace to factory settings. The second thing is set my high and low lbs per hour. I then measured my pounds per hour and they were almost dead on. Started up the stove and I have heat. My problem now is dialling in high and low burn setting . Everytime I start the stove I get something different out of the heat output. So I'm gonna wait longer and they suggest running it on heat setting 3 for a few mins before dropping down to 1. We will see how it goes. I've played with the df and it seems to run better on auto plus I want to hook up thermostat so I need to run it on auto.

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When you set the high and low pph, you need to only set the low to begin with, leave the high alone. Once you get it burning on low good then mess with the high pph.

When lowing the low pph you will need to allow the stove to burn on 3 until you have a decent bed of coals going or the stove will go out.

As far as the DF running better on Auto. That's what you want but, you still haven't said if you are adjusting the DF setting on low DOWN.

You have lowered your pph, if you don't lower the low DF setting then you are sucking the same amount of air through the stove as you were before changing the low pph. You need to lower the DF or you will not get heat, you will continue to get less heat and maybe even burn the fuel out.
 
On auto it adjusts the df I think cause it can't be changed when on auto. The df is set at 1 when I'm on heat 1. I'm only working on the low side right now. I'm going to have to try leaving it on 3 for a while like you said to build coals then drop it down to 1 and see what happens. I have no build up at all but haven't ran it more that 3 hrs at a time. I can even open the manual draft some if I need more air.

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On auto it adjusts the df I think cause it can't be changed when on auto. The df is set at 1 when I'm on heat 1. I'm only working on the low side right now. I'm going to have to try leaving it on 3 for a while like you said to build coals then drop it down to 1 and see what happens. I have no build up at all but haven't ran it more that 3 hrs at a time. I can even open the manual draft some if I need more air.

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The DF should have parameters of 0-500. Most of the stoves running that 4 button board the low DF factory default was 230. I don't know what yours is. You change those the same way you change the pph except you use the DF UP/DOWN buttons and the AUX UP/DOWN buttons. And then push the ON button for the changes to take affect.

You should be able to run the stove in AUTO all the time. As far as running in MANUAL the lowest DF setting will still be what the stove goes down to, that doesn't change from AUTO to MANUAL, same with the high DF setting.

The only time I use the manual draft is when starting the stove, or shutting the stove down to get it to burn out faster, otherwise it is closed all the time thereby using only outside air for combustion.
 
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Are you talking about the c6 df low level control and c7 the high level control

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Are you talking about the c6 df low level control and c7 the high level control

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The parameters on the stove will only be changed at the low and high, it's a proportional control panel. Just like you changed the high and low pph, while the only changes seen are on the high and low pph the other heat range setting are proportionally changed between the high and low.

Same with the DF settings. What ever the board shows you when you push the DF up/down and AUX up/down are always the highest and lowest setting for the draft fan, it doesn't matter if you have the DF set on 4, 5, 6, whatever. I know its hard to explain in type but you need to adjust that lowest DF setting since you lowered your pph setting, less fuel needs less air and you will get more heat from that lower setting.
 
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I appreciate your time and patients with me. I'm glad we have a place to go for the info on just about anything fire heating related. I'm gonna finish my coffee and give it a try. Thanks again

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I appreciate your time and patients with me. I'm glad we have a place to go for the info on just about anything fire heating related. I'm gonna finish my coffee and give it a try. Thanks again

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No problem, like I said I know it's hard to explain in words online sometimes. Just remember, it doesn't matter the mode the stove/furnace is running in, you can change those setting anytime, just like you changed the pph. Just remember to write down any numbers that flash on the board when pushing buttons, so if you change them and don't like what happens you can easily go back to the other settings.
 
So I think I got the bottom set with your help FirepotPete. But I'm still going to do some testing. I took it up to the upper level 5 and I couldn't control the exaust temperature. So I set it back down to heat setting 1 but it's taking a while to get back down. I used your df trick on the lower setting and I had to raise it 15 numbers. I felt like 5 pph on heat setting 5 was way to much I worked it down to 3.5 and just gave up for now. I need time to think about it some.

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I'm looking for some help on my lower feed setting. When using thermostat for example heat range 3 if the thermostat doesn't call for heat then the heat range goes back to 1 as a pilot light. So some people set it at around 1 lbs per hour and some people are higher around 2 or so. Just wondering what people's thoughts are on this? Im still havinf problems starting tbe stove and getting same result. I started it tonight put it on heat setting 1 and got 100 degrees more in heat on front of door. Thanks

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So every day I start it up and try to dial in the lower setting point I get something totally different then I had the day before. I just want 350-400f but I can't get there. I figured out my high vent temp is set at 230f and I keep going over that which reduces heat. I've tried increasing my draft but doesn't seem to lower vent temp that much and I've tried lowering the pph and I just can't get there. My pph was 1.38 last night tonight I'm up to 1.75 and rising I think.

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Sorry I missed your last couple of posts, been busy. I'm a little confused. Are you running it with a thermostat? If so when it reaches the target temp the stove will slowly go back to the low setting that you have it set at, it just doesn't drop out to the lowest set point. It also does this when ramping up, it's not immediate.

Increasing your draft will not drop the temp of the exhaust, it will do the opposite and at some point you will find the fire out because it cant' feed enough fuel for the amount of draft. You would only see a drop in the draft temp once the stove can't provide enough fuel.

As far as pph, that will depend on your set up and the pellets you are using. Best bet is to just get a nice burn going, with as low a pph setting that you can, then adjust the df down until it isn't burning good and then adjust it back up for a clean burn without going out.

5 pph in my opinion is usually to high. I have mine set a 5pph but have never used it, but I have 9 heat ranges, I never run higher than 7 and very seldom above 5. If you set high HR pph down to 3.5 that should be OK, it will give you a range of temps closer together between HR's.