St. Croix Hastings - fire fades, burns out

[JudgeSmails]

10 Year old Hastings starts, burns (not ideal flame), goes out w/ 3 LED flashing (POF) after varying amounts of time.

This issues started the end of last burn season.
Last year I replaced the combustion fan and POF switch.

Replaced the POF again this year (apparently some quality issues with POF switches) but still run into same issue.
The stove will start normally, and I have a nice yellow flame, but it's not what I'd call ideal...too fat and wavy.

Eventually, the flame will fluctuate and get to a point where the active flame is diminished, pellets continue to feed and smother the flame, stove will quit with #3 POF error, burn pot full of pellets.

I've adjusted the damper basically to closed to more than recommended open over burn cycles...letting to run for 15 min. or some between adjustments.
physically removed stove from house and cleaned the bejesus out of it.
Replaced door and glass gaskets.
swapped combustion fan (w/ spare)
jumped POF and vacuum switches in separate instances
confirmed voltage to POF
finally replaced control board as a 'nothing else left' fit of defeat....

My assumption is potentially too much air...but non of the above affect outcome currently.

Any thoughts suggestions, etc? Thanks in advance.

 

[kchace]

If your flame isn’t right, you have an airflow problem. My suggestion is you either have a clog in the combustion air path someplace or the “plenum” that the combustion fan sits in is clogged. The other possibility is an air leak in the ash pan door, or you’re not pushing the Ash Shaker Rod back IN all the way. This is the rod directly above the ash pan door. if this isn’t pushed back in all the way then the air flow can go around the burn pot and you get a terrible flame.

Ken

 

[JudgeSmails]

If your flame isn’t right, you have an airflow problem. My suggestion is you either have a clog in the combustion air path someplace or the “plenum” that the combustion fan sits in is clogged. The other possibility is an air leak in the ash pan door, or you’re not pushing the Ash Shaker Rod back IN all the way. This is the rod directly above the ash pan door. if this isn’t pushed back in all the way then the air flow can go around the burn pot and you get a terrible flame.

Ken

Thanks for the reply Ken.
I agree with you, my first thought was airflow. I've had the stove apart, rapping the interior of the burn box w/ the rubber mallet, leaf blower sucking the ash out of it, etc, etc. Intake and exhaust pipes clear, combustion fan cleaned, blown out, even swapped...gone back to the shaker rod every couple days for a sanity check, where it should be.
This is why I'm completely flummoxed.

 

[bogieb]

Make sure the shaker isn't coming apart from the rod causing it to be angled so not fully retracted even though the rod is. Also make sure there isn't a big cake of hardened ash keeping it from sliding all the way - moisture over the summer could have done that.

I'm assuming that you have kept it clean behind the 3 ash traps - but just make sure the path between the 2 upper traps is clean and you can push a small hose or wire hanger thru there. And then of course there is the one behind the ash pan.

 

[JudgeSmails]

Make sure the shaker isn't coming apart from the rod causing it to be angled so not fully retracted even though the rod is. Also make sure there isn't a big cake of hardened ash keeping it from sliding all the way - moisture over the summer could have done that.

I'm assuming that you have kept it clean behind the 3 ash traps - but just make sure the path between the 2 upper traps is clean and you can push a small hose or wire hanger thru there. And then of course there is the one behind the ash pan.

Thanks for the suggestion. Clean around the shaker. Rod took a couple turns to fully tighten up, but didn't affect shaker closing completely. Took a peek from the underside, from the ash pan side too...all clear.

I'm regular with the cleanings and recently removed it from the house for an uber-cleaning going after this issue. Truly a head scratcher...

 

[JudgeSmails]

Thanks for the suggestion. Clean around the shaker. Rod took a couple turns to fully tighten up, but didn't affect shaker closing completely. Took a peek from the underside, from the ash pan side too...all clear.

I'm regular with the cleanings and recently removed it from the house for an uber-cleaning going after this issue. Truly a head scratcher...

So I cleaned the stove out again...although I had gone through it thoroughly a few weeks ago when it was removed.
No change. Starts fine, burns seemingly normal for a while and then the flame fades, eventually flames out, pellets pile up and shuts down with the POF indicator.

I ran through the cycle again, paying attention to the flame, auger indicator LED and auger sound/pellet drop.
Tested the manual auger feed and no visible action (still have sides off), then on the regular cycle nothing, then auger turns and feeds...
When it does not turn there is no torque on the motor, so it's not indicating an obstruction and I just had the hopper/chute completely empty.

I would not assume an auger motor would fail intermittently...has anyone experienced anything similar?

 

[tlc1976]

My thought is that it’s starving for air and drawing a vacuum until it quits.

Do you have an outside air kit, to draw combustion air from outside?

If not, have you done any improvements to your house to seal things up when this started?

 

[rickwai]

It needs the leaf blower trick. It 99% of the time solved this issue. There is a few st.croix threads currently with same issue and better explanation

 

[JudgeSmails]

Thanks for the responses.
The stove is very clean, I regularly clean it out and burn quality pellet (including the leaf blower treatment twice in the past month)
I have outside air in take, can feel the draft in the burn box when stove is idle.

The stove can burn seemingly normal for well over an hour in some instances...then what I assume is random lack of fuel snuffs the flame, pellets start feeding again, but not enough ember to light it up. varying amounts of pellet feed filling pot until POF shutdown cycle...

I monitored the stove last night, control board auger light would turn on, no action on the auger motor/shaft, two cycles later motor turns.
Curious if intermittent motor behavior has been experienced by anyone else...I would assume this would be a working or not at all part.

Plan on removing the motor/shaft for a closer look today...been in there 10 years.

 

[Mt Bob]

Yes,an auger motor can stop intermittently,when hot, especially if it is really dirty inside. Also, it could be your control board is dropping out, not supplying voltage all the time.Or a bad connection somewhere in the wiring.

 

[rickwai]

The bushing for the auger can get stiff and slow or stop the motor. If you open the side so you can see the motor and push auger button you can see the motor turn or not Most likely not the control board. I think it is a 2 rpm motor. With hopper empty and motor remover you should be able to turn the auger with minimal resistance. If it takes channel locks to turn it, it needs pulled out and clean up auger end shaft and use a little oil on on it before reinstalling. When pulling auger you may need to use a large screw driver or pry bar and pry it out from inside the hopper prying on one of the flights on the auger. Stuff builds up on the end of the shaft where it does into the bronze bushing you cant see up in the top

 

[JudgeSmails]

Thanks All.
Auger motor and rod came out easily, nothing jammed in there restricting movement. Cleaned up the rod, washer, etc with scotch brite pad to knock off any baked on pellets dust, etc. attached the new motor and been burning consistently for close to 24 hrs. It wouldn't stay lit for more than 1 1/2 hours previous.

The random nature of the auger motor failure was unexpected for me...made the wrong assumption that this would be an all or nothing part.

 

[bogieb]

Thanks All.
Auger motor and rod came out easily, nothing jammed in there restricting movement. Cleaned up the rod, washer, etc with scotch brite pad to knock off any baked on pellets dust, etc. attached the new motor and been burning consistently for close to 24 hrs. It wouldn't stay lit for more than 1 1/2 hours previous.

The random nature of the auger motor failure was unexpected for me...made the wrong assumption that this would be an all or nothing part.

Glad you finally got it figured out after all the frustration!