Harman Insert Glass Cracked

[jrex]

I finally finished my install and had a few cold damp days so I could try this thing out. I was excited to do a test burn. Lit it using the manual mode and ran it for my 30 minutes to an hour. Had to turn it off because the room temp was up to 74. Next day I decided to try it again but wanted to try the auto settings using the thermometer that is wired to the unit. Stove lights and I proceed to do some things around the house. My son comes to get me and says the stove is burning really smokey and the glass is turning black. I go check it out and the glass has a crack from one side to the other side. What?? Turn the stove off and call the dealer.

Dealer asked me when they installed the stove. I tell him you didn't I did it. He wants to come out and check the install. I was leaving for vacation the next day so just got back to him and his son said just bring in the door they are booked for the next few weeks.

So my question is what could cause the cracked glass. Here is my guess. It is cracked from about the top screw that holds the glass in on the inside to the same screw on the other side. Screws were too tight from Harman and when it heated the glass cracked. Anything I am missing? Anything on the install that could cause the glass to crack? I am also guessing the smoke on the glass occurred after the crack. Not sure even if it is burning poorly causing the black smoke why the glass would crack.

Thanks!

 

[jrex]

Well dealer agreed screws were too tight from Harman and they popped in a new piece of glass and I was on my way. On down side he said my glass was way too dirty for such a short burn time and believes I am not getting enough air through my OAK. Only thing I can think of is the OAK pipe is squashed or terminated sideways into the chimney blocking air. I already had the top cap on so I couldn't look down and see it.

 

[jrex]

What are possible reasons for cracked stove glass? My dealer installed a new piece of glass after the glass in the new stove cracked. The 1st piece looked like it was from screws too tight. It cracked after 2nd burn but the 1st burn was only like 30 minutes. Well today I lit the stove and the new piece cracked after about 30 minutes of run time.
1. screws too tight: eliminating this since he didn't tighten them too tight since that was the reason we "thought" 1st piece broke
2. possibly warped door: not sure if this is a possibility or not although would have to be warped from Harman since it is a new stove
3. any chance of lack of make up air would be a cause? Think it would just burn black. I have an OAK installed half way up chimney but not sure if it is kinked or not.
4. stove not level? My hearth is 2 different heights but I used the leveling bolts in the back to level and seemed good to me left and right and front and back

Thanks for any input. The dealer is going to love me.

 

[Peterfield]

There could have been a defect in the glass that the heating/cooling exploited.

 

[Overfireinthehole]

Why does your oak only go halfway up the chimney? No oak would be better than that.

 

[jrex]

Actually the Harman instructions indicate it only needs to go up a few feet past the masonary damper. I have the Harman top cap with louvers on my chimney cap so the OAK breathes from the top. To me nothing wrong with the OAK install other than not being able to confirm the OAK is not kinked or blocked. The SS liner does go all the way out the top.

Peterfield I am not sure about a defect because that means 2 would have had the defect. 2 pieces of glass both broke within an hour or so of starting the stove. When they installed the 2nd piece I didn't inspect the door. Wonder if there could be a high spot on the frame.

I probably will take back to the dealer. I don't mind paying for the glass if the screw up is in my install but can't come up with a reason for the glass crack.

 

[Overfireinthehole]

Actually the Harman instructions indicate it only needs to go up a few feet past the masonary damper. I have the Harman top cap with louvers on my chimney cap so the OAK breathes from the top. To me nothing wrong with the OAK install other than not being able to confirm the OAK is not kinked or blocked. The SS liner does go all the way out the top.

Peterfield I am not sure about a defect because that means 2 would have had the defect. 2 pieces of glass both broke within an hour or so of starting the stove. When they installed the 2nd piece I didn't inspect the door. Wonder if there could be a high spot on the frame.

I probably will take back to the dealer. I don't mind paying for the glass if the screw up is in my install but can't come up with a reason for the glass crack.

I’ve always used top plates that seal off the top of the chimney entirely to keep it all dry and creature free. Some of the older Harman install manuals still have stubs listed as good installs, but they definitely create a lot of problems down the road. Do your local codes require oak, and is your house tight enough that air exchange is a problem? I’ve seen Oaks cause more problems than they solve, and 90% of the time the unit breathes better without one. What did your flame look like when you first fired the unit? Did it immediately lacked up? Did it overflow pellets from the beginning? Did it take longer than 5 minutes to light? What model Harman? Have you performed a pressure check? It sounds an awful lot like your having airflow issues that are causing the firebox to hold a lot of heat. IS YOUR COMBUSTION COVER LOCKED IN PLACE? I’ve seen baffles get put in wrong so that a stove doesn’t draft correctly, causing the center medallion bracket to warp and break. One other thought. If you slam your door with the handle pulled up, can you hear the flapper? A flapper being stuck or lacking draft to move it will give you a nasty burn every time.

 

[jrex]

See if I can answer some of these questions.
I probably don't need an OAK since the stove is in a 20x21 room with a 14' window wall and it is old construction from the 50s. There is a door with 15' of the stove as well.
I thought the flame looked fine. I was burning in the manual mode set at only 1.5.
I would say it took about 5 minutes for the fire to start. I could see sparks early on but no flame for about 5 minutes.
This is the 52i insert with the touch screen.
Not sure what you mean about combustion cover locked in place. I did remove the baffles and medallion for install and pretty sure I have them in correctly.
I can do 2 things. I can do 1 of 3 things. Pull the OAK pipe out and replace it with a longer peice to get near top of chimney but its only 17' tall so I am not that far away, just remove the oak pipe and see if it can draw from room, or remove the OAK kit entirely.

 

[jrex]

Any issues with disconnecting OAK pipe from the insert cage and running it like that. This should allow the OAK to just suck air from the room and allow me to eliminate the pipe install as the cause. Plus I should be able to disconnect it kind of easy by pulling the insert out a short distance.

If this works and I have more air should I see the fire ignite faster? What other differences should I see?

Thanks!

 

[Overfireinthehole]

That should be fine, assuming you don’t have a local code requiring outside air kids on solid fuel burning appliances. There are seven pieces that can be removed from the front of a 52 I without using a wrench or socket. All of these can impact air flow if not seated properly . You’ve got the three cast-iron baffles, the flame guide, the burn pot clean now on the bottom of the burn pot, The combustion cover which is located on the lower right hand side after you take the cast-iron baffles out, and finally there is a long skinny cover that runs along the bottom of the firebox. The long skinny cover and the combustion cover are both held in with latches. Five minutes is normal for a start up by the way .

 

[jrex]

Thank you. Do you happen to know if there is anything from new that you need to do with the combustion cover under the baffle such as remove anything. I never touched it. The baffles and medallion all looked to be installed correctly. It seems to me the easiest thing to do is remove the OAK pipe and let it pull from the room. Only issue is if I should put a new piece of glass in for the test run. If it is not the problem I risk another piece of glass. Not sure if I can get this special glass from a glass shop vs going back to the dealer.

If it is the OAK I have to assume the exhaust is so much harder then the intake that it is actually pulling the glass "into" the stove. This does not seem logical to me. The glass did crack at the top right screw that holds the glass in. It is not tight. I can twist the glass lock flange that holds the glass in.

 

[jrex]

I just pulled out the baffles and the left baffle was not inserted correctly. The left side of the baffle was behind the steel bar which is part of the stove. Looks like baffles should be in front. Not sure how much this affects air or would it really cause the glass to crack?

 

[Overfireinthehole]

I doubt that would cause it to crack. On new installs I always take everything out to make sure nothing got left in there that shouldn’t have and to make sure they are sitting right.

 

[jrex]

I also pulled the cover off the exhaust fan and ran it in diagnostic mode and that fan seemed to work fine. After I put the baffles back I lit a lighter and held below and could see the flame being sucked up the exhaust by fan. Tomorrow I will pull the OAK pipe.

 

[jrex]

How does this fire look? This is the 1st burn I had and only ran for about 30 minutes or so. I forgot to plug in the thermometer when I did the install so I just burned it in manual mode. It was not that cold out so I had to play with the setting and eventually backed it down to 1.5. Its my assumption all blowers and feed are in auto but it does not run off a temp just the manual mode set point. The glass did not crack on this day and fire was turned off after about 30 minutes or so.

Next day I pulled the insert out and installed the thermometer. I fired the stove back up in Auto using temp set point. It seemed to run smokey and at some point I think I switched back to manual mode and the glass soon cracked.

Last fire was just in manual and the glass cracked again.

How does pellet stove glass compared to glass in a wood stove? I know my wood stove has reached 800 degrees with no issues to the glass. My buddy asked if I could have over fired the pellet stove causing the glass to crack. I said even if the fire was HUGE can't believe the stove temp reached even 500 in such a short time. If the flame is too big doesn't that eliminate the OAK being a cause (blocked OAK = little flame).

 

[Peterfield]

How does this fire look? This is the 1st burn I had and only ran for about 30 minutes or so. I forgot to plug in the thermometer when I did the install so I just burned it in manual mode. It was not that cold out so I had to play with the setting and eventually backed it down to 1.5. Its my assumption all blowers and feed are in auto but it does not run off a temp just the manual mode set point. The glass did not crack on this day and fire was turned off after about 30 minutes or so.

Next day I pulled the insert out and installed the thermometer. I fired the stove back up in Auto using temp set point. It seemed to run smokey and at some point I think I switched back to manual mode and the glass soon cracked.

Last fire was just in manual and the glass cracked again.e).View attachment 230984

Looking at your picture, it appears that your flame is burning out toward the glass, almost horizontal in appearance. I am looking at my 52i right now and its flame is burning up over the medallion, parallel to the baffle plates and nowhere near the glass. Maybe it’s just a reflection in your pic but thought I’d point that out just in case.

 

[jrex]

Yes after I looked at the pic I thought the flame looked large. I wonder what would cause the flame to burn like that. Thanks for the feedback.

 

[Overfireinthehole]

Lack of airflow causes a large lazy flame. Sounds like you pinched the oak when you put the room sensor on

 

[jrex]

I can see that but could a large lazy flame cause glass to crack? I just slid out the insert and pulled the 3" OAK pipe out of the stub. Lit the stove with the cracked glass. Seems OK to me. Will post a pic of the flame tomorrow.
This is the touch screen model. I assume when I run off of room temp the stove automatically adjust feed and maybe fan to maintain set point. There is a separate icon on the touch screen for feed rate. It was set pretty high like 60%. I assume when I ran in constant burn mode it ran at whatever the feed rate was set at which may have been high.

 

[Overfireinthehole]

In constant you are adjusting feed and draft when you change settings. In room temp you can adjust room blower speed and feed rate independent of your set temp.

 

[jrex]

Ok good to know. Guess I will order a new piece of glass and lower feed rate down to a bare minimum and work my way up. I kind of familiar with the process as I have a coal stoker boiler that works similarly although there is less messing with the exhaust blower.

 

[jrex]

So here is my flame last night after I removed the OAK pipe and lowered the feed rate. I think the feed rate may have been as high as 75% on the factory pre set setting. I tried to take a pic of the unit operations under diagnostic mode and the feed rate was still in the 40% range. I may lower it even more and start out low. How does the flame look? Still not sure how a large flame cook crack the glass.

I did call a local glass shop that sells stove glass. They order it in pre cut and the cost was $160. Think I found a piece in a Harman box for $200 with the gasket material.

 

[jrex]

I read the manual on the TC last night and do not see a way to adjust the combustion fan motor speed. Is this something that is possible? I would think the speed would be adjustable dependent on draft. On my coal stoker there were 2 combustion fans. One was large and ran only a small amount of time based on a timer. The small fan ran all the time but there was a flapper on the intake to regulate the air flow. Now maybe I need all the combustion fan on the pellet I can get but the fan seems kind of loud not a mechanical loud just high flow loud.

I ran the combustion fan in TEST mode last night.Max RPM was 3010 on full voltage. Max RPM set point was 2603 RPM. Min RPM set point was not that much lower than Max. I don't remember the value but think it was like 2400 RPM.

 

[jrex]

I was looking at the front body of the stove to see if anything was coming into contact with the glass. The small allen head screws all seem to be out of the way of the glass. There are 4 holes on the stove that match up with the 4 glass retain screws. The top 2 are straight through about 1/2" in diameter. The bottom 2 are not straight through meaning they only go part way through the steel. Now they may still add enough space for clips to sit in. Are these bottom 2 screws normal? If anybody has a chance to post a pic of the front of the their accentra with the dorr open that may be helpful.

My new glass should arrive today. I am debating between installing it and firing up the stove or calling the dealer to come out and look at it.

 

[jrex]

So tonight before I replace the glass I put lip stick on the 4 glass retain clips and close the door. The lipstick was transferred to the stove body on the 2 hinge side clips but not the latch side. I also noticed the door gasket is pretty beat up already on the hinge side even though the door has not been opened more than a few dozen times. So if those clips are touching the body of the stove when it heats up is there enough pressure to cause the glass to crack? I looked at the hinge and don't see any issues other than the bottom hinge pin sits all the way down and the top pin it is not all the way down. Door reveal looks to be fine with it closed.