Heatilator CAB50 Problems with combustion

[kps513]

I have recently installed this Heatilator CAB50 in my basement. The pictures show the back of the stove and the outside pipe. The other pictures show what the burn pot fills with in 12-18 hours. When the stove was first installed I had no troubles and the stove would relight without a problem and the burn pot would be ok for days at a time.

Right now I have burned about 35 bags so far since buying this stove. Since getting the incomplete burn I have to make sure to dump the burn pot every twelve hours as it is half full or more. Last week I noticed that the exhaust combustion blower was not turning real fast. There is a white mark on the outside of the plastic edge on the fan and it was visable spinning slower then it should be. I then attached the leaf vac and sucked out the pipe and it blew out quite a bit of ash. I think it was more then it should of been for just burning 35 bags.

I then restarted the stove and the exhaust blower was spinning faster now since I couldnt see the white mark any longer. The fire looked better then it has and was able to run for nearly 24 hours before the holes were plugged up on the burn pot. Now two days later I am back to having a full pot after 12 hours of running.

Heatilator support was not helpful as they wanted me to contact a dealer. I cant get the local dealer to call me back.

To me it seems like there is a problem with the exhuast blower not running at peak RPM. I do not think this stoves control board varies the speed of this fan. Could it be one or the other or a combination of the both?

Any help would be greatly appreciated.

Thanks

 

[heat seeker]

I think you need to remove the combustion blower and clean it and the pipes from stem to stern. The leaf blower trick is for after you have done the cleaning, not instead of a cleaning. The improvement, however temporary, shows that you are on the right track. Your exhaust system needs a thorough cleaning, and now.

 

[smoke show]

What kind of pellets are you burning???

 

[kps513]

I will remove it tonight and give it a complete cleaning. It really stinks to have to go through this with such a few bags used in a brand new unit

 

[SmokeyTheBear]

While you are at it is that pipe that is through the wall going down bubble?

If it is you are not helping your combustion air flow at all.

Then after you clean out your plumbing and can describe your flame, color, activity, etc... we can discuss things like damper setting.

 

[kps513]

I have burned 4 different brands with the same results. All have been premium hardwood with less then 1% ash. My Primary one used is "1st Choice Premium" from Great Lakes Renewable Energy. I have also adjusted the feed rate from the factory middle position all the way down to the smallest opening but the incomplete burns still happen

 

[DexterDay]

What kind of pellets are you burning???

Yep. What pellets and also check your door gasket for leaks. Do the dollar bill test. Open the door, place dollar bill in, close door and see if you can pull it out. Do this in several spots along all 4 sides of door.

If the gasket is leaky, it will rob the burn pot of air. That stove is essentially a Quad. That burn pot should be gettin plenty of air. I had a bad gasket at the end of last season and limped through. Got some "caking" in the pot. But not that much.

Have you tried a different pellet? And as heat seeker said above, do a full cleaning and then use the leafblower.

The color of the ash looks good. Just need to find why your not getting the airflow needed. Are you getting the lottle holes at the bottom of the pot? If its the same as the Quads, there should ne 4 little ones on the front and 4 littles holes on the back (very bottom of pot, above clean-out plate).

 

[DexterDay]

Nevermind the pellet thing. I type to much.

No damper on these models Smokey. Just 3 heat settings. High, Med, and Low and an adjustable feed plate inside hopper.

 

[SmokeyTheBear]

Nevermind the pellet thing. I type to much.

No damper on these models Smokey. Just 3 heat settings. High, Med, and Low and an adjustable feed plate inside hopper.

OK Dexter, in that case the OP should understand that once the build up starts it will get worse as time passes.

So if the stove is feeding too many pellets to start with making changes while having the condition without a full stem to stern clean out is not likely to get them anywhere.

If that outside "horizontal" run is doing down hill the OP has severely restricted his exhaust, it MUST ALWAYS BE RISING when it leaves the stove. Horizontal runs are supposed to have a minimum of 1/4 inch per foot of rise.

 

[stoveguy13]

what temp do you have the thermostat set at and are you running on high med or low?

 

[kps513]

Tonight I did another full cleaning and again quite a bit of ash came out the vent pipe after 5 days. The outside pipe did have a very slight downward pitch which I corrected tonight.

I keep the thermostat at about 70-72 but do find that most of the time if it shuts down it will not ignite again due to to much ash in the firebox.

I also did the dollar bill test as suggested and found the only part of the door it sticks well is between the hinges on the left side of the door. The side of the door near the latch the dollar pulls out very easily. I have noticed that side of the glass also gets a black smoke streak. Do you all feel the gasket it not correct with the dollar pulling out so easily? Even though the stove is new?

thanks again to all for the advise. I will take new pictures in the morning after 12 hours running of both the glass and firebox and see what the opinion is.

 

[kps513]

Forgot to answer one of the questions. I leave the stove in Med.

 

[DexterDay]

A new stove does not ensure tight gaskets. Is there an adjustment on the handle. I just looked and rubbed on one at a Forum members shop a few weeks ago. But didnt notice the door latching mechanism, as it was burning and didnt want to open the door, while it was doing so.

If you can tighten the door latch, try that. A leak is a big culprit for bad burn. That caking looked similar to mine (again, just not that bad, that soon) when my door gasket was bad.

Mine was bad, door adjustment couldnt help. Adjust if possible.

 

[kps513]

Pyro there is no adjustment to the door. The door latch is a cam and by tightening the nut inside does tighten up the action of the handle but doesnt have any effect on the gasket. Should the gasket hold the dollar real tight ?

 

[SmokeyTheBear]

You might want to see if that door has adjustment capability. The pieces of paper should come out but they also need to present resistance. It is also possible that your latch assembly is a bit loose.

Anything that interferes with the air going through the burn pot and the pellet pile is a problem, anything that reduces the size of the air paths in the stove from above the burn pot through and including the termination cap on your venting will interfere with the air flow.

If too much ash sticks to the impeller blades they will not create the airflow that they did when clean and sharp edged.

If any of the holes in the burn pot are no longer the same size as when new it interferes with the air flow.

Bad gaskets or doors out of adjustment present another air flow issue this time it is because the air doesn't go through the burn pot.

If the burn pot isn't seated correctly air will go around the burn pot instead of through it.

Out of specification venting or venting that is not properly installed will present too much resistance to the combustion blower slowing the airflow down.

Additional things that need to be considered is in the case of lower level installations (basement for example) the chimney effect is larger and that means less air flow through the stove via the air intake (this is something that can be corrected via an OAK installation).

Any air handling device inside the house may be able to reduce the available air flow through the stove.

You should adjust your feed plate when the stove is clean for a proper flame.

Yes I know that is a long list, but even low amounts of airflow changes make huge differences in burning pellets.

 

[DexterDay]

Should hold it fairly tight. If the nut tightens it, then that is an adjustment? Right. Otherwise it wouldnt tighten. Can you post a pic of the door latching mechanism?

The are owners and dealers that can better tell you how to address the latch. If it pulls very easily and cant be adjusted anymore, than that is causing a leak.

Do you have any incense or candles around. (Incense is best) Take the incense and run it around the outer edge of the door. Pay attention to where the air was on the stove is, so you dont mistake it for a leak. If smoke is pulled into that area. Then the gasket is leaking and robbing the pot and pellets of air.

 

[DexterDay]

Also, 1 other note. Is there a "Stove adapter" on the back of the unit connecting the stove to the flue? And with the 3 ft of horizontal, 2 - 90* bends, and the 1.5' (looks like it) of vert, gives you almost 14' EVL. Thats on the border of a bad burn there. Especially with the 90*'s so close???

Thats one more thing to look at. Also installing a clean-out T may aid in the cleaning process a little. May or may not?

 

[kps513]

The pipe going through the wall is at least two feet. Exterior walls are 6 inches. Do you think if I change the pipe going through the wall to a single 12 inch then go up 4-5 feet then direct out 12 inches will be a help?

 

[SmokeyTheBear]

The pipe going through the wall is at least two feet. Exterior walls are 6 inches. Do you think if I change the pipe going through the wall to a single 12 inch then go up 4-5 feet then direct out 12 inches will be a help?

You want the shortest possible horizontal run consistent with the distance the end of the termination cap must be from the house.

I have other issues with the venting but it has to do with what happens on loss of power.

 

[SmokeyTheBear]

It would be helpful if you looked up EVL (equivalent vent length) and found out what the stove's limit is for the vent size you have.

Usually (but not always) 3" venting can only be used if the EVL is 15 or less above that and the venting needs to be 4" starting at the stove adapter.

 

[stoveguy13]

Forgot to answer one of the questions. I leave the stove in Med.

try running it on high

 

[kps513]

After running last night for 11 hours at medium the burn pot is at least 1/4 full (can not see any holes in the pot any longer) This is the picture of the glass door on the latch side. Not sure if this is leakage or not.

 

[humpin iron]

quality of pellets-- the 2 90's so close together ain't helping. Should have gone straight out, tee, up 48, 90, jet cap. My shop would have done it in 4" pipe. Unburned pellets, most of the time there is nothing wrong with the stove. Cleaning- cleaning- cleaning, which relates to quality of pellets

 

[DexterDay]

I would definitely look more into the gasket. I can run on Low for a week without build-up (if running constantly). There is an air flow problem to the pot, be it the venting, dirty stove (you said its clean though), or leak (or all 3).

Bad gasket will cause problems.

 

[SmokeyTheBear]

quality of pellets-- the 2 90's so close together ain't helping. Should have gone straight out, tee, up 48, 90, jet cap. My shop would have done it in 4" pipe. Unburned pellets, most of the time there is nothing wrong with the stove. Cleaning- cleaning- cleaning, which relates to quality of pellets

Let's also add in it is likely any ash traps are loaded up and doing the vent thing ain't even close to getting those completely emptied even when using a leaf blower. Then we have the area above the burn pot going on the way out to the exhaust system.

Since we are chasing an obvious air flow issue we might as well hit all of the bases, is there anything blocking or in the air intake on the stove?