# Harman P35i Chimney Liner Rumble



## Mr. Heat Miser (Nov 6, 2010)

I just finished installing my Harman P35i pellet insert and fired it up this morning. I installed it myself, took my time,  and followed all the instructions exactly. The stove works great and my entire downstairs warmed up within an few hours of lighting it. The only thing is, I am experienceing a low frequency rumbling noise every so often. It almost sounds like when a car drives by your house with the giant subwoofer in the trunk. It can get quite loud at times. It seems to be being caused by the exhaust blower. I think it's the chimney liner vibrating, almost like when you blow across the top of a beer bottle, but I am not sure. I used a 4" 316Ti Stainless Steel Chimney Liner and ran it to the top of the chimney, then capped it with a terracotta flue cap with a roof and a round opening and band collar connection. I also used the lintel kit which secures the inserts frame into the fireplace opening by tightening some threaded rods against the lintel bar at the top of the fireplace opening.

Is rumbling a known or common problem with chimney liners? Any other ideas on what this noise could be? If it is the liner, any ideas on how I might correct it?

Thanks for any suggestions.


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## MCPO (Nov 7, 2010)

Has anyone taken a draft reading  ?


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## HarmonP35i (Nov 7, 2010)

did you install a outside air kit?


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## imacman (Nov 7, 2010)

Mr. Heat Miser said:
			
		

> .....4" 316Ti Stainless Steel Chimney Liner and ran it to the top of the chimney, then capped it with a terracotta flue cap with a roof and a round opening and band collar connection......



Can you post pics of chimney cap set-up?


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## summit (Nov 7, 2010)

they used to have the same problem on the first runs of the accentra insert. check your flame guide (the cast iron trangle widget above your burn pot)... does it have a curve to it? If it is flat, get one with a curve, it'll solve the problem. I know the sound you mean: it sounds like there is someone blowing over the top of a giant beer bottle thru your liner.


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## Mr. Heat Miser (Nov 8, 2010)

Gio said:
			
		

> Has anyone taken a draft reading  ?



Not yet... when I got to that part in the install, I asked the dealer if they typically measure the high and low draft, and they said no, that only about 1 out of every 100 needs an adjustment because the draft is tested and set at the factory. I wanted to test it, but didn't have a meter myself. I have asked the dealer about the rumble, and they are going to come out and take a look at it. They will bring their draft meter and diagnostic meter. I'm curious what they will find, because as I say, I meticulously followed the install instructions, checked and double checked everything before I fired it up. I'll post their findings after they come out on Wednesday.


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## Mr. Heat Miser (Nov 8, 2010)

HarmonP35i said:
			
		

> did you install a outside air kit?



No, I asked the dealer about it several times, and even had them come and take a look at my house and they said the outside air was not necessary. My house is 2500 sq ft and tight, but not super tight. I asked several dealers about the outside air and they all recommended against it.


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## Mr. Heat Miser (Nov 8, 2010)

imacman said:
			
		

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Here's a pic of the chimney cap I used


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## LIpelletpig (Nov 8, 2010)

This is a common problem with Accentra Inserts.  Not sure if it transitioned to your model as well but my stove is going on season 3 and it makes the noise on start-up and on a HIGH burn.  Once the stove is warmed up it goes away.  I originally didn't have an OAK and last year I installed an OAK and noticed the stove didn't burn well and it made no difference.  I removed the OAK and the stove burns much better.  No reason why but the OAK was installed to manufacturer specs.  If you search the forum under Accentra Insert Roar or rumbling you'll get some info on the issues as well.  Your install sounds fine and it doesn't sound to me as your issue.  For curiosity sake, while the stove is making the sound open the pellet hopper lid.  See if the sounds goes away.


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## mdlyen (Nov 8, 2010)

I just had a P35i installed and encountered the same rumbling sound.  The dealer seemed to think it had something to do with the gasket on the hopper lid.  Something about it allowing air into the hopper and causing the rumbling.  He has had a couple customers complain about the same thing.  It does seem to only happen when the stove is cold so once it warms up, I forget all about it.

I will post back if my dealer comes up with anything.  He already had the Harman rep out to visit one of the other customers (if you believe that)...


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## MCPO (Nov 8, 2010)

Mr. Heat Miser said:
			
		

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The dealers answer was somewhat evasive . The draft reading should be done after the install since it usually has more to do with the chimney (vent) than the stove. However you ae doing the right thing in having it checked.


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## MCPO (Nov 8, 2010)

Mr. Heat Miser said:
			
		

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That`s BS, typical dealer`s sales pitch.  Most of them prefer to say outside air isn`t necessary . I think soley because it makes an installation easier, quicker, and cheaper.  BUT only slightly on those three counts, at least on most typical installs.
 That said it probably isn`t the cause of the chimney noise either.


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## Lousyweather (Nov 8, 2010)

Gio said:
			
		

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yea, a bit tough to check the draft if you dont have the meter.....i second the above....any rumbling we ever heard was the flame guide....there's 3 different types of Harman guides, the oldest and most common being a flat one, but the correct one has a concave top...this solved any issues we had (2-3) with "rumbling units"....the ones I heard sound more like a train going by slowly


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## tjnamtiw (Nov 8, 2010)

First, with an install into an existing chimney, an OAK is just about impossible unless you want to bore a hole through the back of the chimney.  Possibly, you could use the ash cleanout door, if it has one, but not very easy to do and the insert will probably sit right on top of it.  The run up the chimney for the OAK would be too long.
Next, when you had a roaring fire in the old fireplace, you never noticed rumbling??????  I'm sure you did, but you got used to it and it died down when the fire slowed down.  Same thing with your insert but the smaller diameter pipe exaggerates it.  People who have never burned a real fireplace have never heard the 'roar' before and get all bent out of shape.  I'm not talking the roar of a chimney fire now!   %-P   That one you'll NEVER FORGET!


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## Lousyweather (Nov 9, 2010)

the outside ait kit is an accessory with an insert........but you dont have to punch a hole into the firebox......it pulls the air out of the space between the liner and the old masonry chimney for its outside air.


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## tjnamtiw (Nov 10, 2010)

Lousyweather said:
			
		

> the outside ait kit is an accessory with an insert........but you dont have to punch a hole into the firebox......it pulls the air out of the space between the liner and the old masonry chimney for its outside air.



Not if you do it right and seal off the top of the chimney with a plate through which the liner goes!  It's a dead air space if you also block off the smoke shelf, otherwise you will end up pulling the air from the room.


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## Nicholas440 (Nov 10, 2010)

I have a Quadrafire Castile insert and its going on 3 years now, and it rumbles but  mine rumbles due to the round design of the firepot and the holes it has in it.  Actually,  I really like that rumbling sound,  I can turn away from the flame and hear that rumble and I can picture in my head exactly what the fire looks like because Ive watched it while that rumble sound was going on.  Its not continuous it dies down, and comes back depending on the size of the fire, and the air coming into the firepot.    

I'll bet your Harmon has the same type of issue, with its firepot design.  Watch your fire for a while and note  at what point the rumbling occurs if its similar to mine it will be when the fire reaches a medium size or larger.  I normally dont hear the rumble when the fire is real small .  As I say I really like that sound it reminds me of when my fireplace was roaring years ago when  I burned logs.   Some people compare the sound to blowing across the top of a bottle too.


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## Lousyweather (Nov 10, 2010)

tjnamtiw said:
			
		

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when using the Harman outside air kit, "doing it right" ISNT sealing off the plate.


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## tjnamtiw (Nov 10, 2010)

Lousyweather said:
			
		

> when using the Harman outside air kit, "doing it right" ISNT sealing off the plate.



Well, how does Harman recommend that you DO terminate the flex liner at the top of a 20' chimney AND use the outside air kit?  If you don't seal off the top of the chimney, how do you keep rain from getting in?  I'd like to know, because I have two inserts that don't have OAK's.

And what is Harman's recommended maximum run for the OAK piping?


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## Lousyweather (Nov 11, 2010)

tjnamtiw said:
			
		

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perhaps you should look at page 22 of your Accentra Insert manual........if your is old, or you cant find the manual, you can go to Harman's website and download a manual which MAY be more recent than your own. Most, if not all, of the info is in the manual, if one takes the time to look.


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## tjnamtiw (Nov 11, 2010)

Lousyweather said:
			
		

> perhaps you should look at page 22 of your Accentra Insert manual........if your is old, or you cant find the manual, you can go to Harman's website and download a manual which MAY be more recent than your own. Most, if not all, of the info is in the manual, if one takes the time to look.



No, if you look at my signature, you'll see I have two Quads.  I was asking what Harman knows about OAK's up chimneys that, evidently, Quad doesn't know so I could add an OAK to mine.


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## c_mantle (Nov 11, 2010)

I hope you resolve your issue!  I'm making the decision this week to go with either a P35i or Accentra insert.
Can you give me any guidance?  Other than cost...why'd you pick the P35i.
The feed range of the Accentra is very attractive but I think the P35i is more efficient.

Any feedback would be helpful.


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## Lousyweather (Nov 12, 2010)

tjnamtiw said:
			
		

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well, then, like I said, the manual is available online, and should answer your question


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## camdids (Nov 12, 2010)

The Harman Manual gives a diagram clearly showing the outside air Pipe ending inside the Chimney ,Halfway up. If sealed at the top and at the Damper , the only air is through the Brick Chimney. Isnt It??

#1 Installing into an existing fireplace
method provides excellent venting with
100% outside air which is the most efficient operation
of this unit. This method also provides natural
draft in the event of a power failure.
A 4 inch stainless steel flex pipe is needed for
the flue pipe, and 3" aluminum or Stainless Steel Flex
Pipe is used for the intake.
In Canada and some places in the US it is required
that the vent pipe extend all the way to the top
of the chimney.


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## tjnamtiw (Nov 12, 2010)

Lousyweather said:
			
		

> well, then, like I said, the manual is available online, and should answer your question



Remind me to take you off my Christmas list, Lousysomething.............................


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## Delta-T (Nov 12, 2010)

the diagram also shows the whacky "top extension kit" that you'd need to use (or something similar) to separate the intake from the exhaust. in the end this configuration is sort of cost prohibitive for most people. I've never told anyone they couldn't do it, but i do explain that in many circumstances its not necessary, though you may like to have it. So many people balk at the cost of installation as it is, why get them all riled up about fresh air intake, when it is not "needed" (even if desirable) or is going to add more $$ to the bill that they already want to haggle about? Raise your hands members with an insert who have a full reline and fresh air intake running up the chimney in parallel.....not so many I think, for these very reasons I'd assume.


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## tonyd (Nov 12, 2010)

I clean my insert outside on a dolly. I had the cast iron top removed to lighten the load and reinstalled it outside. When I lit the stove I heard the rumble. I noticed the weather stripping sticking out around the hopper (not the lid). After repositioning the gasket the rumbling stopped. Pulled the gasket out, rumble, sealed hopper, no rumble. It is definitely   A   cause for the rumble.


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## Lousyweather (Nov 12, 2010)

tjnamtiw said:
			
		

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damn! gonna be a bleak Christmas, or Channuka, or Kwanzaa now!


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## Mr. Heat Miser (Nov 13, 2010)

c_mantle said:
			
		

> I hope you resolve your issue!  I'm making the decision this week to go with either a P35i or Accentra insert.
> Can you give me any guidance?  Other than cost...why'd you pick the P35i.
> The feed range of the Accentra is very attractive but I think the P35i is more efficient.
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Okay, here's what I found... the dealer came out and looked at the stove. I left it off so it was cold when they got here. After pulliing it out and inspecting the rear of the stove which all looked good he lit the stove and watched it burn. It didn't take long to start making the rumbling sound... he discovered that by opening the door latch slightly that it would stop... upon further inspection of the door, he decided it may be that the door wasn't making a good seal. The next day he brought another door over from the display unit in the showroom and we quickly took of my door and  replaced it with the one he brought. When we started the stove it didn't take long before the rumbling started, and proved the door theory wrong. 

I had mentioned the flame guide as suggested by two other contributors to this thread, and he said he had the curved one in his truck if I wanted to try one. So he left one with me and I shut down the stove to let it cool. A few hours later I removed the flat flame guide that came with my P35i, and replaced it with the curved flame guide. I definetly like the way the stove burns much better with the curved flame guide! The rumbling has decreased by 90% and now it is a pleasant rumbling that sounds like a normal fire sound, rather than a sort of resonant frequency vibration that could get very loud and have long durations with the flat flame guide in place.

I also notice that the flame is more consistent across the burn pot and the ash on the edges of the burn pot is more completely burnt with the curved flame guide.

Thanks alot you guys for suggesting the flame guide!... It seems to really improve stove performance and greatly reduce unwanted vibration.

As for picking the P35i over the Accentra, I really liked the smaller look of the P35i insert, and my back really liked carrying that up the 21 stairs to my back deck and around a corner into my living room. I also knew that the stove should be good and reliable because it is a P Series stove made into an insert, and the P Series stoves have a proven track record. The Accentra is a nice stove, but it is such a monster, and the P35i is so much smaller and only 7000 btu's less in output I believe. I also just liked the looks of the P35i better for my family room. The lower price is also an attractive feature.

I have a 2400 sq ft house with an oil fired force hot air furnace and two zones. So far the P35i has had no problem heating my entire downstairs to 70 degrees with temperatures outside in the upper 30's and lower 40's and the oil furnace off. I think it will do a nice job this winter offsetting my oil usage significantly. Last year I used 520 gallons total, I'm hoping to get that somewhere in the 350 gallon range or less.


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## tjnamtiw (Nov 13, 2010)

Lousyweather said:
			
		

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  It sure as HELL won't be Kwanzaa or any Muslim holiday!


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## Lousyweather (Nov 13, 2010)

dang....not to show my ignorance, but is Kwanzaa muslim?


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## tjnamtiw (Nov 13, 2010)

Lousyweather said:
			
		

> dang....not to show my ignorance, but is Kwanzaa muslim?



No, Kwanzaa is a Black holiday and I couldn't come up with the name of a Muslim holiday unless they celebrate Best IED of the Year.


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## Lousyweather (Nov 13, 2010)

tjnamtiw said:
			
		

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Ramadan?


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## tjnamtiw (Nov 14, 2010)

Lousyweather said:
			
		

> Ramadan?



Yea, that's it, Ram-it-in


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## Mr. Heat Miser (Jan 28, 2011)

P35i update! Today is January 29th, 2011 and I have been burning my P35i for nearly 3 months now, and I am loving it! So far I have reduced my oil usage by half, as compared to last year at this same time.

I have burned 39 bags of New England Wood Pellets so far this season, and I think the 2 tons I started with will be just about right to carry me through until spring. 

Here's how I have been using my pellet insert to offset my oil usage. My house has a oil fired forced hot air furnace with 2 zones. We keep the downstairs zone set to 58 at night, so the furnace rarely comes on. The downstairs zone is programmed to jump up to 66 in the morning just before we get up. While the oil furnace is warming up the downstairs zone I give the pellet stove a quick cleaning each morning by scraping the burn pot, quickly brushing the heat exchanger with a small paint brush, cleaning the glass, and fill the stove with pellets. This takes about 15 minutes at most. Then I light the pellet stove at about 7:30am. By this time my programable thermostat sets the downstairs zone back down to 58 and the pellet stove maintains and heats the entire downstairs zone for the rest of the day until I shut it down at about 10:30pm. The oil furnace never fires again for the rest of the day. Even on the coldest days, I have not used more than 1 bag of pellets.  

During the day, the upstairs zone is set at 58, and at night it goes up to 64 while we are up there sleeping. We use an electric blanket to warm up the bed, then shut it off before we fall asleep. This uses far less electricity than having the furnace set at a higher temp, which heats the entire zone.

Rarely will the heat come on in the upstairs zone during the day, and it only comes on a few times during the night while we are up there.

By shutting down my pellet stove at night and giving it that quick cleaning each morning, it keeps the stove very clean and burning efficiently. I have performed 2 full firebox cleanings so far (after every 15 bags or so) which takes about an hour and a half, and I empty the ash pan about once every week or week and a half as needed.

I have found the maintenance to be very easy so far, and don't mind it a bit. It is part of my morning routine now, and only takes a few minutes. By not letting the pellet stove run all night, I am not heating my downstairs when I am not in the space, and I make my supply of pellets last longer. With the oil heat set at 58 overnight, the furnace rarely comes on because the zone never cools below the set point. Yes, it is cool downstairs in the morning, but firing the oil for 15 minutes warms it up quickly. And no... it does not cost more to heat the downstairs zone up from 60 to 66 than it would if I left the thermostat set to 66 degrees all night.

Will make a final post at the end of the season to report total oil offset with my 2 tons of pellets and this method of using the pellet stove.


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## crwalter (Feb 3, 2011)

Mr. Heat Miser said:
			
		

> P35i update! Today is January 29th, 2011 and I have been burning my P35i for nearly 3 months now, and I am loving it! So far I have reduced my oil usage by half, as compared to last year at this same time.
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Now that you've opened the bin a few times, have you noticed any problem with the paint scraping off the hinges to the lid? The display in the store near me has almost all of the paint on the hinges scraped off due to opening and closing the lid.

I'm about to pull the trigger on this model.

I have an appointment with the installer for measurements of my metal fireplace.

TIA,

Charles


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## Mr. Heat Miser (Feb 3, 2011)

crwalter said:
			
		

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Hi Charles,

I just looked at my hinges, and they look good. One small chip in the paint on the right hand hinge, but that doesn't bother me. That may have been there all along as far as I know anyway. You can buy some flat black touch up stove paint and give them a coat after each season if you want. The floor models in the store take a beating from people opening and closing and touching them over and over. Not to worry, I have been very happy with mine so far, and the maintenance is really easy too. That's a big plus! I shut mine down each night, and give it a quick cleaning in the morning before lighting it, which keeps it nice and clean and burning great!


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## crwalter (Feb 3, 2011)

Thanks for the reply.

I know that the floor sample takes abuse, even though it has not been set up.

The hopper lid hinges are looking really bad on that unit. I don't even know what year that one was made.

Since that would not be a reflection of "real world" use, I thought I'd ask. I'm not worried about an occassional touch up, just constant touch ups. Glad to hear that this should not be an issue.

The installer will be at my house at 4:00 p.m today to take measurements. I'm not sure what he'll say, since I think the existing zc fireplace is too small. The guy in the store thought I was nuts when I was asking about removing the existing zc fireplace and putting in the insert with a zc kit.


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## Mr. Heat Miser (Feb 3, 2011)

crwalter said:
			
		

> Thanks for the reply.
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> The hopper lid hinges are looking really bad on that unit. I don't even know what year that one was made.



If it is the P35i you are looking it, it was made in 2010. Last year was the first year they made the P35i. I think it came out in the Spring of 2010 sometime. It is however based on the P-Series Harmans that have been around for many years and are a proven design. Some modifications were made to make it into an insert, and to keep the costs down.


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## crwalter (Feb 4, 2011)

Thanks for the clarification. Yes, that's the one I'm getting.


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## summit (Feb 4, 2011)

get the flame guide for a new accentra insert and your 35i will work fine. this flame guide has a curve in it that kills the turbulence associated with this noise.


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## smwilliamson (Feb 15, 2011)

camdids said:
			
		

> The Harman Manual gives a diagram clearly showing the outside air Pipe ending inside the Chimney ,Halfway up. If sealed at the top and at the Damper , the only air is through the Brick Chimney. Isnt It??
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> #1 Installing into an existing fireplace
> method provides excellent venting with
> ...



This type of install requires a special cap which allows outside air to be sucked into the chimney from the top and a sealed damper plate below. Look and read the technical drawing closely!


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## Irish916 (Aug 31, 2011)

Mr. Heat Miser said:
			
		

> P35i update! Today is January 29th, 2011 and I have been burning my P35i for nearly 3 months now, and I am loving it! So far I have reduced my oil usage by half, as compared to last year at this same time.
> 
> I have burned 39 bags of New England Wood Pellets so far this season, and I think the 2 tons I started with will be just about right to carry me through until spring.
> 
> ...



Thank you for sharing your experience on this unit.  This unit was recommended by my local stove store to replace my ZC propane insert.  Does anyone have any idea what a good price would be to have this installed?  I saw another poster said an installer was coming.  I want to make sure I don't get taken to the cleaners.  Thoughts?


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