Project Stove - 2016 Ravelli Francesca Hopper Fire - Troubleshoot, Recommission, then Install

[lookingforowls]

First time poster, long time lurker. I'm a 15 year pellet burner with a Lopi Yankee Bay fireplace insert. Over the years I've done all the basics on that stove, maintain and clean it religiously, troubleshoot and replace parts as needed w/much help from the forums. Wanted to pick up a second stove this year to further supplement my outrageously ridiculous electric rates in CT, at the beginning of the pandemic when I started to work from home in March my electric heat usage for my home office, wife's home office, two kids remote "school rooms" went through the roof.

I came across and picked up a 2016 Ravelli Francesca on FB Marketplace for $500. The seller was totally honest about the issues from the 2020 heating season, is moving, and not planning on reinstalling the stove . HE had a tremendous amount of aggravation w/the dealer when trying to identify the issues and quite frankly just wanted to move on from the stove.

Long story short, after the hopper fire some work had been done on the stove by a dealer, they replaced the exhaust blower not 100% sure they ever found the root cause of the hopper fire as the former owner got frustrated w/the tech and fees they were trying to charge him.

As the story often goes w/hopper fires, it was a pellet backup into the hopper that lingered, stove never shut down, smoke in the house, etc etc. Only change the former owner had noted was that he had just switched to softwood pellets, I myself have always burned hardwood.

There's some obvious areas we all look with hopper fires but I wanted to do a deeper dive on the stove, "recommission" it as safe, before I consider installing it in my house. And yeah there's a pandemic going on so I'm looking for some projects

I've started to look for additional documentation on the stove other than what was provided to me, plan on taking and posting pics of the tear down, clean up, troubleshooting and testing etc. Have already eyeballed a bunch of obvious issues; loose connections, loose convection blower which is missing screws, loose door contact, missing gaskets on the hopper access door, etc.

I need to locate a parts list/schematic so I can verify what I am eyeballing as the safety's that should have shut the stove down, and attempt to fire it up outside and trouble shoot the startup/running sequences, simulate some failures on the appropriate contact points to identify a root cause.

Been browsing the forums for a few days leading up to this post, have some good ideas on how to approach this, but would love some feedback from forum pros on how they would approach this little pandemic project.

 

[Pelleting In NJ]

Attached are the Ravelli/Ecoteck Tech Manuals, one for the Non-RDS stove, one for the later RDS stove (I don't know which one you have). RDS stoves have an airflow sensor on the intake air tube. The airflow sensor is used to automatically regulate the combustion blower speed (draft) to maintain a constant air/fuel ratio as the exhaust gets restricted due to ash buld-up in the burnpot and the exhaust passages/flue. If it gets too restricted you get an alarm message that the stove needs cleaning.

Also attached is the Maintenence manual for for a similar model stove.

I am not sure what can cause a hopper fire in these stoves, although I had noticed that with extremely dusty pellets, that there were sometimes flames going up the drop-tube, when the dust ignited. (I stopped the stove and dumped all the dusty pellets as soon as I saw the flames in the drop tube.)

These stoves do not have a gasket for the hopper door. They just rely on the hopper full of pellets from allowing the draw of air into the firebox. (These stoves have the firebox under suction from the combustion fan).

The safety systems on these stoves are:
- Hopper door switch to disable the auger motor.
- Firebox door switch to disable the auger motor.
- Overtemperature switch on the hopper, stops the auger motor and initiates the shut-down sequence.
- Exhaust temperature sensor: stops auger feed and runs combustion blower and room blower on high if the flue gas temperature is too high. During normal stove operation, this sensor is used to determine if the stove has ignited the pellets, and how long to run the combustion blower during the shutdown sequence.
-RPM sensor on the combustion blower to detect if it is rotating slower than it should be, due to a mechanical blockage, or a bad motor or motor bearing.
-"Vacuum" switch (actually it is a pressure switch) which detects if the flue (after the stove) is blocked or excessively airflow restricted.

 

[johneh]

I have seen two hopper fires both were caused by poor
maintenance Very dirty stoves that were not cared for
A clean stove is a happy heater

 

[Pelleting In NJ]

Any progress to this?

 

[lookingforowls]

Any progress to this?

Just started to put the panels back on and hopefully test fire today. Cleaned everything up as best as I can tell at this point.

Q's :

For the front door switch, assume it's supposed to be in the closed position, mine looks like there's a gap between the switch and metal bar that are supposed to push the switch to fully closed, same as the lid switch ?

Also I found the "common red wire" that goes from the lid switch to door switch had the jacket stripped from the wire and covered with electrical tape, odd no ?

Briefly plugged in and powered up yesterday, the combustion blower fired up immediately and it threw an ignition error code, shut it down right away as I wanted to throw a small combustion pipe extension on it during test fire up and honesty need to read through the tech literature that you folks so graciously provided.

*To be continued *

 

[lookingforowls]

Also, the small amount of pellet dust/particles that was left is this thing was super super sticky, I don't burn softwood in my Lopi, only hardwood, this stove was supposedly burning softwood pellets when it went up in smoke.

 

[Pelleting In NJ]

Yes, the door switch should be depressed when the door latch is locked closed. The mounting depth of the switch can be adjusted to achieve this. Some people have reported that the wires of the door switch, or the switch terminals melt, due to the heat in that area, maybe that was an attempt at rewiring or bypassing that switch. The wires to the switch should be connected to the Common (C) and Normally Open (NC) switch terminals.

You have an RDS stove (the red thing on the intake air tube is the airflow sensor).

I burn hardwood and softwood pellets in my Ravelli and don't have any issues.

 

[lookingforowls]

Thank you Pelleting in NJ, door switch adjustment was the first issue to rectify as pellets were not dropping because the switch was way out of adjustment with no possibility of making the closed position. Stove is running all the way through the ignition phase but does not light, thus kicking off the no ignition error.

During one of the test ignitions, once the burn pot is filled, I opened the front door and confirmed the glow plug is lit however I am thinking it may need to be adjusted closer to the burn pot as the pellets are not igniting and it looks like it has about a 1/2 in gap between the end of the ignitor casing and glow plug tip, it is one of the items to check off in the service manual flow if the stove is not igniting. Looks like a simple adjustment, unless someone tells me otherwise

 

[Pelleting In NJ]

There is a gap between the end of the ignitor and air-tube that surrounds it. There is also a gap between the end of the air-tube and the hole of the burn-pot. These gaps are OK because the system blows the hot air from the ignitor onto the pellets, there is no direct physical contact between the ignitor and the pellets. The hot air is what ignites the pellets. When the stove is turned ON, the ignitor and auger are activated, then about a minute (or so) later the combustion blower should start, which is what then provides the airflow over the ignitor element.

If the exhaust temperature sensor does not see an increase of temperature after a certain amount of elapsed ignition-phase time, then the stove trips the no ignition alarm and shuts everything down.

 

[lookingforowls]

There is a gap between the end of the ignitor and air-tube that surrounds it. There is also a gap between the end of the air-tube and the hole of the burn-pot. These gaps are OK because the system blows the hot air from the ignitor onto the pellets, there is no direct physical contact between the ignitor and the pellets. The hot air is what ignites the pellets. When the stove is turned ON, the ignitor and auger are activated, then about a minute (or so) later the combustion blower should start, which is what then provides the airflow over the ignitor element.

Correct, all of the above sequencing checks out fine, my last two attempts I pulled the burn pot once it had filled, and the glow plug on the igniter was bright orange as if it were functioning normal. The pellets looked like they were getting toasty/blackish but did not ignite which is why I am thinking the igniter position may need to be adjusted, as indicated in the tech manual (RDS Rev2 5/6/2012) p. 18 troubleshooting:

Pellets Come Down But Stove Does Not Turn On -> (Non Centered Resistor in Brazier Hole OR Draft in flue issue)

Will tinker some more tonight, cool tech on these Ravelli's, coming from the Facilities industry myself, working with various building management systems/infrastructures over the years, impressed to see this kind of tech in a pellet stove, but I could see how a homeowner could be easily frustrated by one of these stoves. My Lopi insert is just plain dumbed down and simple compared to these stoves.

 

[Pelleting In NJ]

It could also be that some of the control operating parameters were incorrectly changed by someone, some of which control how long the stove waits for ignition, before tripping the no-ignition alarm/shutdown.

 

[lookingforowls]

I thought about that too, going to have to read and tinker.

 

[Pelleting In NJ]

You should also remove the airflow sensor from the intake tube, and clean any dust off of it.