Harman XXV Pellet Stove Review

jeffreypalmieriNovember 18, 2005

First I have to say THANK YOU to everyone who has put so much good information on this site. It made it possible for me to make an informed decision instead of a decision based on marketing materials and salesman hype. Special mention to Xanndra who adds a ton of rational and practical input to the board. Hopefully this review will help others going down a similar path. I shopped and researched for about 5 months and bought a Harman XXV pellet stove that was installed last Tuesday (11/8). Here's some background information and how things are going so far.

I have a 2100 square foot cape cod built in the mid 50's with oil heat. Of the 2100 square feet 1500 make up the original house and 600 make up the addition off the back with a family room downstairs and fourth bedroom above it. The floor plan in the original section of the house is pretty open. The addition rooms only have a single doorway into each but are on a separate heating zone. Insulation is probably average and I've replaced all the single pane windows. My goal was to heat the main house and the fourth bedroom with the pellet stove and minimize oil use in the family room in the addition.

I was originally looking at the Harman P68 and the Quadrafire Mt Vernon. I picked Harman over Quadrafire for four reasons. First I read a lot of recommendations on this board. Second I went to a dealer that sold both and when you take a look at the brands side by side there is no question that the Harmans are better built and sturdier. Third I called 5 dealers in the northeast that sell both Harman and Quadrafire and every one told me without hesitation that they would recommend a Harman over a Quad. Fourth was the Harman warranty. Nothing against Quadrafire but I felt much safer spending my money on a Harman. So I went to buy the P68 and my wife saw the XXV. Naturally I bought the XXV even if it might end up a little under powered on the coldest days. Happy wife = happy husband.

Install took only 2 hours and there were no problems. I went with the outside air kit so I could put the stove right under a window and direct vent it straight out. I'm a pretty practical guy but I have to say this stove looks great. Again the construction of the stove is impressive. The casting is perfect; the fit of everything is right on and solid.

It's been running every night since 11/8 and most days as well. The furnace has been silent the entire time too. Last night we had our first cold night - my thermometer read 21F this morning. The stove room was 71 (stove set on room temp 70), the rest of the house was upper 60's, and the family room in the addition was 64. So far everything is great.

The first five days we had the stove the feed motor was very loud. Noticeably louder than the fans and you could hear it from an adjacent room. I called the dealer and they were sending a tech out with a new motor within the week but I called it off because it quieted down to a normal level. It's good to know I'll have quality service when needed.

I had preordered 4 tons of premium pellets in September from a local place but couldn't pick them up until early November. When I got there they had been "accidentally" sold and I'd bet at a much higher price. Should have trusted my instinct when they didn't require me to pay for my order up front. So the dealer I got my stove from was able to get me pellets at a very good price but they are high ash. The price was about $50/ton below the current premium prices so I took them. The stove burns fine. I've been scraping the burn pot every other day or so and it's been pretty clean - nothing blocked, plugged or clinkered up. I will have to empty the ashes weekly and maybe every five days or so when we hit January/February. Last night (7pm - 8am at 21F) I went through about 3/4 of a bag which seems a little high. Not sure if that's because I'm heating 2100 square feet, the pellets are high ash, or it has something to do with the room temp mode which is my next topic.

I've read a lot on this board about the Harman room temperature mode. From my experience so far the jury is still out. I coiled my thermostat wire and taped it to the back of the stove. Like many I don't like the fact that the fan will stop to keep the room from overheating when the fire is at it's lowest. For the most part setting it at 70 has kept the room between 71 and 72. There have been some times I've checked and the thermometer was up in the mid 70's but it could be the heat being blown from the stove (the thermometer is fixed to the opposite wall). I need to tinker more with a second thermometer over longer periods of time. I'm also interested in running in stove temp mode once we get steadier cold temperatures to get more heat out and hopefully use less pellets. I'll post more when I learn more.

This has almost turned into a full length book. Hope it helps. I'd be happy to answer questions if anyone has any.


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Nice post, I have the P68 and love it. I fooled around with the sensor and have finally left it at about 4 1/2 ft on the mantle the length of the cord from the stove. The room pretty much stays a a constant 70 degrees. I found a good spot, good luck with your stove. I also own a cape in Massachusetts built in the fifties. I haave R19 in the attic but in 2 weeks I have a contractor comining out to add an additional R30 Blown in over the existing batts.
Should see a difference to R49 you think?

    Bookmark   November 18, 2005 at 5:36PM
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Thanks so much for the thorough review. My Harman Accentra is due to be installed in late Dec. and it's nice to be able to read great posts while I wait! I was looking at the XXV, but thought it might dwarf my >600 sf downstairs. Keep toasty!

    Bookmark   November 22, 2005 at 1:02PM
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Hate to throw cold water on every one...Harman units are good...but, wait till you REALLY put the customer service to the test...like I did....see your'e all new customers...once they got your $$$$$$$ and you require them to honor their warranty...by, bye nicey...read... my experience with harman....it's somewhere on the board...
I would not make this up and it is not an experience that I desired to go through.....and Harman is the direct result as to why I bought a pellet stove....not from them(I had a coal stove - Mark I)...

    Bookmark   November 26, 2005 at 3:33PM
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I'm happy to hear about the good experiences, and I hope I won't have to test the warranty. I ordered a Harman XXV and it is expected to be installed in January.

    Bookmark   November 28, 2005 at 11:47AM
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To Steven2. We're not all new customers and it really depends on the dealer you buy from I guess. I have nothing but accolades for my dealer, and Harman itself.
I had a Harman Advance, nice stove, but I wanted more capability as I added a sun room, so I bought the P-68.
Within 4 months of buying the Advance, there was a serious crack in the steel strap that holds the rear accordian heat exchanger. The dealer promptly came out and returned the stove to Harman. So I wouldn't be out of a stove, they "loaned" me their demo Advance stove, right from their showroom, and did all the removal and installation. Harman ended up replacing the stove with a new one.
I'm really enjoying the P-68, and suggest that you choose your dealer carefully. I find the P-68 *far* easier to clean as all you have to do is clean the burn pot and brush the accordian heat exchanger and the sidewalls into the ash pan.
Then a simple cleaning of the combustion blower area.


    Bookmark   December 3, 2005 at 8:45PM
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have had nothing but great experiences with the harman dealer we bought from. They have been prompt and VERY nice to work with. We had the room sensor switch causing a problem on high and the dealer insisted on coming right out and replacing the entire circuit board. Other than that we really haven't had any problems.

    Bookmark   December 4, 2005 at 3:28PM
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steven2 -
i would be really interested in reading about your experience. I have tried looking for it with no luck. Are you able to point me in the right direction?

    Bookmark   December 12, 2005 at 12:00PM
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I hate to burst everyones bubble, before you go and shell out $3k for a Harman XXV I have heard there is a problem with quite a few buzzing which Harman has not yet come up with an sure fix for and is not at all willing to replace them. They just keep telling their dealers to go out and try and fix them, and have asked them to try to implement 3 or 4 technical bulletin fixes which haven't worked. If you want to read about this problem, go to hearth.com and search their bulletin board for XXV. It's quite an ongoing saga.

    Bookmark   February 23, 2006 at 1:33AM
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I asked my dealer about the XXV Friday, his response was Harman issued "1 tech bulletin" early February regarding a few stoves in the field with a buzzing distribution blower. Here is the latest post from hearthnet.......

Pete S Posted: 26 February 2006 02:13 PM
Burning Hunk

Total Posts 28
Joined 2005-12-29 The Harman rep came to my home yesterday and implemented the factory designed fix (metal band clamp) which I truly believe is the final cureall for this issue. I am very comfortable that this fix will work (I know I have said that before, but I really think this did it).

He explained that the Harman finally found one with this issue that their engineers could analyze (not sure why they didnt just have mine shipped back to them 4 months ago). As I understand their explanation, Harmans engineers say the buzz is generated by the magnetic field emitted by the distribution blower motor which causes a very high frequency low amplitude vibration in the shroud . Their fix he implemented adds a large metal clamp band (aka hose clamp) strapped around the exhaust line. The clamp tightens up the contact between a section of sheet metal (contiguous with the shroud...I think?) which is overlapped onto the exhaust line, and prevents them from tapping against eachother. This metal band clamp looks like the stove could have been designed with it (doesnÂt look hokey at all, like mine and other posts have indicated).

As it is very clear that high frequency vibrations in the shroud sheet metal were causing it to tap on someother section of metal, we also cut the tip of the sheet metal screw off which connects the two sections of the shroud together (just in case the tip of it was contracting the distribution blower housing, because based on earliar poking and prodding, it sure did seem like the source of the noise). This sheet metal screw was about 3/4" long, alot longer than it needs to be.

Also as one of the previous fixes was loosening the screws on the distribution blower box, he made sure to that the blower box was replaced back in a tight secure position. I didnÂt want to mention this in earliar posts for fear of getting flamed as a whiner, but during an earliar repair attempt, one of the methods of repair was to back off on these screws to lower the distribution blower down a hair. As after they implemented this fix and the section of gasket fix, the buzz occured with less frequency, but then stove in general seemed to be more noisy (I believe that this was due to this distributio blower box not being mounted securely).

One other thing worth mentioning is that during this fix, we took out the exhaust blower to examine if it needed to be cleaned out. As I have burned close to 2 tons of pellets through this stove, I was expecting to see alot of ash deposits built up on both on the fins and the housing of the exhaust blower. There wasnÂt any. This reminded me of what Harry said in an earliar post (these Harmans burn extremely clean). As he is a Harman dealer I just chalked that up salemen talk. What he said is true, unlike my Whitfield Advantage III which I had for 10 years, this XXV does burn really clean. When I would clean the Whitfield exhaust blower (one to two times per season), it was caked with ash, along with the exhaust pipe. Something about how they designed this stove, the ash doesnÂt seem to get pulled through the exhaust.

In summary, I think this latest fix was it. I know it has has only been one night, but this stove is now running really quiet, more quiet than ever.

With respect to Harman, I still think they should have taken mine or someone elses stove back to the factory back in November, rather than making their customers (Rick in RI, me and anyone else with the issue) and have us beta test their proposed fixes. It would have been a win-win situation for both of us. Neither Rick nor I would have had to endure this buzz for as along as we have had to, and Harman would not have had to have who knows how many potential future XXV buyers read this thread (1,800 plus and counting). Harman makes a solid stove, but needs to work on their customer relations.

    Bookmark   February 26, 2006 at 8:47PM
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I am very interested in seeing this Harmon stove, but according to the harmon website, the closest dealer for me is 40 miles away. My local dealer only sells Quadrafire.

We took a look at the Quad Mt. Vernon yesterday. Very nice stove, but the HarmonXXV is a bit nicer looking, and from what I've read here, better built.

Anyone know of a dealer in Northern NJ?

    Bookmark   March 6, 2006 at 11:01AM
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I found the postings here helpful as we are researching pellet stoves. We have narrowed our choices to a Harman or a Quadrafire. We would like to hear from some Quadrafire owners as well as Harman. Thanks.

    Bookmark   July 20, 2006 at 11:10AM
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Dude do the new mt. Vernon, will burn corn pellets and whatever else, auto klinker drop for corn.

    Bookmark   July 20, 2006 at 10:16PM
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I would highly recommend that you download and go through the install/user manual for each stove. Pay close attention to the maintenance requirements for each stove and take it into account when you make your decision. The Quadrafire is billed as a "trouble-free, fully automatic" stove but when you compare the Quad to the Harman you'll see the Quad requires more work. Now the additional work may be fine for you, but just know exactly what sort of time you'll have to invest with each stove after you spend the money. Here are some differences:

1. The Quad requires that you clean the firepot daily or more frequently when burning dirty fuel and that requires you to completely shut the stove down. Shutting the stove down and waiting for it to cool off takes a while, then you scrape, then the stove has to get running again and bring the house back up to temperature. With my Harman I open the door while it's running, give it a 5 second scrape and shut the door. I did this daily when I was buring high ash pellets and a pellet/corn mix. I did it every other day or when I remembered while burning premium pellets.

2. The Quad ash pan, according to my local Quad dealer, will need to be emptied weekly or more frequently when it's cold and you're burning more pellets. The Harman gets emptied after you burn a ton of pellets - I emptied it once a month when burning premium pellets and could have gone longer.

3. Quad recommends ash removal from the firebox weekly. Harman is after every ton of pellets.

4. Quad recommends a complete cleaning of the firebox after every ton which requires you to remove the baffle from inside the firebox. Harman recommends a complete cleaning of the firebox after every ton but all you have to do is brush down the inside of the firebox with an old paint brush and suck it up with a shop vac.

5. BruceRussel mentions above that "the new mt. Vernon, will burn corn pellets and whatever else, auto klinker drop for corn." I didn't see anything regarding that on the Quad web site but I burned high ash pellets, premium pellets, and mixed corn in my Harman without any problems and the design of the Harman burn pot pushes the ash and clinkers out of the pot automatically. Here's what the Quad manual says regarding high ash pellets: "Poor quality pellet fuel, or lack of maintenance, can create conditions that make the firepot fill quickly with ashes and clinkers. This condition makes the appliance susceptible to overfilling the firepot with pellets which may result in smoking, sooting and possible hopper fires."

Call me lazy but I like the fact that I only have to shut the stove down and do any significant maintenance once a month and it only takes 30 minutes. If I had the time or motivation for more daily and weekly chores I would have purchased a wood stove. Fortunately for you, you're making a decision between two good stoves that will do what you need and look great while doing it. If you like the Quad better and don't mind the extra work then go for it. Good luck.

    Bookmark   July 21, 2006 at 2:15PM
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Have just moved to Massachusetts from Utah. Am looking seriously at the XXV. Aesthetics and build quality look pretty good and the stove will look "correct" in our 250 year old house.

What I am trying to balance is how to amortize the $3000 installed price for the stove plus cost for pellets vs. heating oil saved. Any feelings on money saved by spending lots of dollars on a pellet stove?

    Bookmark   October 10, 2007 at 12:44PM
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Maybe this will help, a fuel comparsion chart from the Pellet Fuels Institute.


    Bookmark   October 11, 2007 at 12:52PM
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Love the XXV. Don't like the Room Sensor setup because I neglect to turn down the thermostat when I'm not going to be home(waste of pellets). I wanted to replace this RS with a programmable thermostat. So I did and I want to share this. A Harmon Technical Bulletin actually addresses this. Acquire any 24v/millivolt programmable thermostat and desired length of two-wire thermostat cable. DO NOT DAMAGE or DISCARD RS probe. Its needed for this mod. Unplug stove. Remove and cut only one wire of the two wire RS cable. Do not alter the probe end. I did this at the stove connector end. Splice one wire from programmable thermostat to one end of this "cut wire" and splice the second wire from the programmable thermostat to the other end of this "cut wire". Reinsulate the cable assy to suit, reinstall on stove, install programmable thermostat whereever and wire to suit. With the programmable thermosat either off or at a temp setting lower than programmed, plug the stove in. I had a 3-blink status light alarm. This alarm indicates that the RS is either disconnected or faulty. Activate run-program or turn on programmable thermostat and the blinking sequence stops. The programmable thermostat is now only a relay that opens or closes the RS circuit. The RS is still monitoring room temperature. Position it accrdingly. The Bulletin states that the RS must be installed in-line as described for this to work. It works!

    Bookmark   October 26, 2007 at 7:23PM
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After much research including the invaluable responses by you all I purchased the Harman XXV.

I was originally hesitant in purchasing the Harman because of issues with the fan and posts about customer service but felt supplying my reasons for choosing this pellet stove over the Mount Vernon will assist in your purchase.

First, you must find a reputable dealer who sells these units. The dealer I purchased from in NH has their techs and sales folks trained by Harman. When I first purchased the unit the ash pan and other items where missing because the factory forgot to include them with the stove. The dealer instantly replaced the parts but also gave me 10 free bags for my troubles. During the sale they filled out the warranty paper, where not pushy and took the appropriate length of time for my comfort in the purchase.

I purchased the outside air kit which made the installation easier. Only thing to say here is if you are installing at an angle make sure you measure the height from the floor and distance from the corner before cutting a hole in the wall.

The stove has great minimal tolerances from a combustible surface which installed at an agle is only 6.25 inches from the corner of the unit to a wall. Not having to sacrifice space in the room was extremely important since the unit is in our living room.

Quality, design and casting is superb. The Harman will burn a 1/2 corn 1/2 wood unlike the Mount Vernon which will do full corn. After reading several posts I found that corn leaves a sticky residue and without finding any information on how the Mount Vernon handles this type of issue it wasn't a strong selling feature.

Harman has been a leader in Pellet technology as a company for over 25 years so the warranty is excellent and having the unit made in the US was a great selling point.

Maintenance on the Harman is quick and easy but I found that the type of pellet used is very important in the Harman. With the 10 bags from the dealer there was an assortment of 5 different brands of which I found two had extremely low ash content. After choosing the brand of pellet it was $18 more per ton but well worth it. I've burned just under 1/2 ton and the ash pan hasn't filled yet. Also, the tool to assist with the maintenance is designed to fit in the pot and other areas.

The dealer recommended using the pellet burn rate option vs. the room temperature mode for my house. I used the room temperature mode briefly but didn't like the unit shutting on an off. It does take a bit of time and energy to figure out burn rate vs. outside temperature to keep the house a consistent temperature. I believe this option becomes a matter of personal preference and what is more efficient for your house. This house is about 100 years old with no wall insulation so the burn rate option works much better.

Closing thoughts. For all perspective buyers, all pellet stoves require a certain amount of maintenance which varies from manufacturer and unit but the cost benefit is well worth it. If you plan on installing yourself make sure and follow the manufacturer installation instructions otherwise you may not obtain full efficiency.

I love the Harman XXV.

    Bookmark   November 24, 2007 at 6:35PM
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I'm from NH too....can you tell me which Harman dealer you used?

After much research both here & on Hearth.com, it seems finding the right dealer is important....I'd like to know I have the right one before I purchase, as opposed to getting a bad one & learning that after the fact.

In case iset123 is no longer active, anyone have any suggestions on how to ensure a good dealer?

    Bookmark   July 16, 2008 at 6:39PM
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I am considering purchasing a P68 Harmon pellet stove to heat a 1500 sq ft cape in MA. Two questions come to mind.
How would one keep the basement only used for laundry from freezing and how would heat reach three bedrooms that are off a short hallway from where the stove would be installed. I look forward to your comments
Regards Steve

    Bookmark   August 31, 2008 at 6:56PM
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I ordered the harman boiler back on july3rd.08 when I ordered it the owner said they would deliver it and put it in the cellar. he delivered it on dec10th. 08 and left it in the yard saying they would be back the next kay to put it in the cellar . well is still sitting in the yard and its the 14th of dec. he called and told me they don.t have the aquipment to put it in the cellar and for us to rent a back hoe from somewhere to do it. after spending 7 thousand dollars on it you think they would follow through on their promise. so be very careful where you buy it. do not buy it from swift building supply in saranac lake ny

    Bookmark   December 14, 2008 at 4:53PM
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I purchased the xxv in January. Since installation, the stove has had a problem with the distribution blower. When the blower is running in any position other than low, it makes a very loud rattling noise. The fan sounds like it is hitting something as it turns. It's a metal on metal sound, and it is not just a minor rattle. It's a very loud clanking noise. It gets louder as the stove heats up. The dealer has been here several time in an attempt to fix the problem. He has even replaced the blower. The new blower worked fine for about a week, then the same problem developed. He is getting me a third blower. What is interesting is that when the blowers were removed from the stove, they worked fine, no rattle. Unfortunatelu, it will take about three weeks for the new blower to arrive. In the meantime, we have to run the stove on the low-blow setting in order to avoid the noise. Has anyone else encountered this issue? The dealer seems to be at a loss. Any help will be appreciated. Other than this issue, the stove has been fine.

    Bookmark   March 14, 2009 at 9:32PM
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I am in the process of researching XXV to buy. A lot of good things, but I am concerned about this problem noise that others described above in 2005-06. I hoped Harman would have effectively resolved the issue by now. Does it seem to you like this is the same problem others describe? Any progress?? Anyone else???

    Bookmark   August 11, 2009 at 1:07AM
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did a lot of research on pellet stoves before buying a xxv from a dealer 6 miles away, southern missouri.
nov. 2010 bought xxv, installed in basement, worked fine till about a week ago [ 2 1/2 months ] then just quit.. coldest night of 2010=2011 . just my luck..
cleaned, read, checked, tried everything.. went to computer [ diagnose ] found a lot of folks been having trouble with feed motors making noise [ mine did before qoutting ] then quit.
now i cant speak for every one but a new, $3,700.00 dollar investment in a product that wont make it three months without trouble [ leaving you in the cold ] just does not make sence..
we grew up with old junk wood stoves [ looked loke oval ,made out of flimsy tin ] and were,= but they never quit on you !!
and called harmon stove , repair ? what ever it will take to get it going till spring.. [ a week ago ! ] not heard from yet..
i belive come spring the harmon will be out and next winter a wood burner will take its place...

    Bookmark   February 8, 2011 at 11:30AM
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Hey guys thanks for the info. I am looking at Pellet stoves and have a Quadrafire GB40 propane stove now. Not sure which I am going with the Harman or Quadrafire. But While talking to the local Harmon dealer he told me that Quadrafire bought Harman about 4 years ago. I guess this is a win win. Sound like this forum leans toward the Harmon and with some very good points. Thanks again

    Bookmark   February 8, 2011 at 2:52PM
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Just curious .... how many of you know that Harmen and Quadrafire are owned by the same company???

    Bookmark   February 13, 2011 at 8:14PM
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Hello All!
I am thankful that you have all left info on the Harman stoves. My HUsband and I are looking (preferably at the XXV) though with all of the common issues with the Auger , I am now wondering if the P 61 or the P68 are not better options for us. We had considered the Accentra, though our home is 1600+ square feet. It would not be a proper fit, I am afraid.
I am wondering this from you: Now that "the honeymoon phase" is finished , would you tell you best friend to purchase one? If not, why ?? If yes, why??
I would hate to spend this amount of cash and have a dud or worse; a danger.
We will most likely add the outdoor Air kit to whichever model we select.
We have a large - open floor plan with bedrooms off of the main room. . With small fans (the ones at the corner of the door frame, we think that we will be able to cut our heating costs in half over the first three to four years (this includes the cost of the stove and pellets and installation)
Thanks in advance for your appreciated response(s)!!!
Stay cool this summer and warm this winter!!!
Kate and Don in NW RI

    Bookmark   August 20, 2011 at 2:06PM
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