Drolet Eco-65 - Bin Auger Operation?

[HVAC_Marc]

Are you sure on the .7" w.c that seems way high! As the burn pot clogs up the draft gauge will go higher about .05" than your normal burn.I would consider .3-.4 normal. At .2 i would say you flue or stove chambers are starting to plug.

it's a brand new burn pot, securely seated. the stove was recently cleaned.

it's only -.7 when it does the prepurge. during any kind of firing it's always down to -.2 to -.4. it's at -.18 at 129 degrees right now.

the software is v.1.08 if it matters

edit - the stove just entered prepurge on a HOT flue. draft is about -.55 to -.6.

 

[hyfire]

The new software must be different mine is verison 07, or they changed the combustion and exhaust fan setup.. I can;t get anything over .35 even on a fresh start with everything cleaned spic and span..

 

[HVAC_Marc]

the combustion fan really cranks up during prepurge. it's really noisy, like a small vacuum cleaner. once the main flame starts it ramps down to a low hum.

one thing that annoys me is that the main blower quits on a new call for heat. the combustion blower then has to cool the entire system down to 98 degrees or less before it will fire again. having the main blower continue to run would get the stove to the start point quicker.

 

[hyfire]

Can you post some pics of the stove internals? and Burnpot..........

 

[hyfire]

the combustion fan really cranks up during prepurge. it's really noisy, like a small vacuum cleaner. once the main flame starts it ramps down to a low hum.

one thing that annoys me is that the main blower quits on a new call for heat. the combustion blower then has to cool the entire system down to 98 degrees or less before it will fire again. having the main blower continue to run would get the stove to the start point quicker.

Sounds like your in pilot off mode instead of auto where if no call heat comes after 30 minutes it must do the comeplete shut down procedure..The convection blower can be set to run on low speed coming off a call for heat.

 

[HVAC_Marc]

i'll get some pictures once our weather clears up. the lighting will be better.

yes, it's in pilot off mode. "auto" wasnt well explained in the book. i will switch it to that and see what difference it makes.

also, the black concrete like buildup on the inside of the burn pot - i can get it off with a hammer and chisel but this cant be good for the pot. i soaked it in water for a week. it didnt even soften it. what removes these concretions?

 

[hyfire]

Don;t let that stuff build up... I clean it off before it gets too hard to remove I just use a heavy duty scraper..Not sure what would take it off..

 

[HVAC_Marc]

 

[HVAC_Marc]

 

[Love the Heat]

The new software must be different mine is verison 07, or they changed the combustion and exhaust fan setup.. I can;t get anything over .35 even on a fresh start with everything cleaned spic and span..

I also get these numbers on a first version of the stove....

 

[MacGyver]

The eco-65 has a very slow start-up, one thing that I don;t enjoy. Alot of energy is wasted to bring the stove up to temp, I agree, pilot on is the best way to combat this problem. Now you up and running I suggest a flue cleaning every 30 bags, you probably seen by my posts some pics of my flue after 30 bags..

Agreed. Even burning on high I find there's a lot of waste. The pellets are getting pushed through so fast that a lot of hot pellets just get pushed into the ash pan.

 

[MacGyver]

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I noticed you still have your tube brush tie strapped to the unit. Have you been cleaning out the heat exchangers?

 

[hyfire]

Thanks for your pics but where is the combustion blower located I dont see it????????

 

[HVAC_Marc]

The brush is used frequently. I store it there for convenience.

Combustion blower is in the last picture, right side. The drum with the motor block behind it. You can also see my clear tube/tee for the minihelic draft gauge.

I fully cleaned the stove again today. After 2 tons of pellets the amount of residue stuck to the sides amounted to about 1/4". It was very powdery and came off easily. Draft after cleaning:

prepurge -.6
low fire -.2 @ 156F
midfire -.3 @ 176F

Im also in contact with SBI engineering to determine why, after the call for heat ends and a new call begins, the stove must reach a flue temp of 98 degrees before the bin auger starts to operate.

 

[hyfire]

Your telling me the combustion blower is the same location as the exhaust blower?????? Show me where the OAK connects?

 

[HVAC_Marc]

Sorry, my mistake. I always forget it's a push/pull system. The combustion air blower is located in the 1st internal picture, right side lower. It is a 4x4x1" muffin fan (like in a computer power supply) that fits on a bracket between the end of the OAK and the steel adapter of the stove.

Update from the engineering staff -

They finally admitted that the flue temp of 98 degrees F is the end of the 'shutdown mode'. Shutdown mode is initiated when the call for heat ends in both pilot on and pilot auto settings. The flue must reach this temperature at the beginning of the next call for heat before any bin auger operation is started. They have 2 "solutions" :

- run it in pilot on mode (and chew up pellets)
- run in in pilot off mode at a very low firing rate so the flue temp doesnt get very high

Neither seem to be an acceptable solution to me. I'm currently designing a circuit that will bypass the flue thermistor on startup and trick the board into thinking that it's cold so the bin auger starts immediately. I need to find the thermistor ohm readings at various temperatures first.

 

[hyfire]

You can get a cheap thermistor setup from china on ebay that has an output relay that is based on temperature and you can adjust the on and off points and the range, but you would still have to make sure the safetys built into the stove don;t get bypassed by this mod. Thanks I do see the combustion air blower now, they really hid it...how does air get to thr burn pot, from the bottom up or side entry? What are those circle of holes in the burnpot? Mine does not have them?

 

[HVAC_Marc]

I was thinking more of a delay-on-make timer tied to the thermostat wiring and a relay. Should be simple enough if i sit down and draw it out.

Air pretty much comes in the bottom center and into the burn pot. The little circle holes are the ignitor. I got my second burn pot from osburnwoodstoves.com (Osburn 7000 Pellet Stove Parts [7000 Pellet Stove Parts:37 SE67101 BURN POT] )

Both of the burn pots are stainless steel and have the little ignitor circle.

 

[hyfire]

I see they re-engineered the stove, they now added a baffle above the door and an upper access to the heat exchanger with tubes... Could we get some pics of this.........No more hybrid OAK and the backdraft shutter has been added. No more air pump for ignitor either...looks like efficiency is now 79% instead of 76%.. The hopper lid now has a seal? But it has vents in it? Pics?

 

[HVAC_Marc]

im on it. next sunny day

backdraft shutter has been removed. it is plastic, and jammed in the slots. it didnt fully open. lightly sanding the posts allowed it to fall out, into the fan. it's a true POS.

EPA stated efficiency is 79.9%. It's actually higher, closer to 83-84%, just on the verge of condensing in the flue, if you're not careful.

 

[hyfire]

Thanks, any pics would be helpful. I actually use a hvac 24 volt electric 4" damper for my OAK when the combustion fan runs the damper opens and closes when it stops. This is so you don;t freeze your room out when the stove is off...It also has a contact that you could wire up with the pressure switch so the stove wont ignite if it does not open

 

[HVAC_Marc]

with the way this stove is gasketed, it's completely sealed. we had 65 mph winds the other night. no leakage anywhere.

 

[HVAC_Marc]

Hopper gasket. The upper door is completely sealed when down. There are no vent slots.



Heat exchanger cleanouts.



Combustion chamber baffle plate, dropped for cleaning.

 

[hyfire]

Thanks for the pics, but could you explain how that baffle works? Do those holes in it line up with the holes in the pipes?

 

[HVAC_Marc]

The baffle swings up and is latched by the assembly seen in the picture. Once closed if forms the bottom of a small collector box for flue gases. The rear panel of the flue collector box is the vertical and then slanted wall with the heat exchanger holes. The top of the flue collector box is the cleanout plate for the heat exchanger.