Performance Loss P68

At the end of last season I started to notice some performance loss with my P68 meaning in general it was not running at the same level as it was the 3 previous years. Those that know me here know that I do annual cleaning once a month and monthly cleaning once a week to eek out every bit of performance possible from my stove and ok yes when it comes to my stoves and cleaning I clearly have OCD.

With that said I am going to tear it apart including doing complete exhaust and Oak examination and cleaning but I really don't think that is the problem.

Sure some are probably saying 4 year old stove no way it should have any part issues but those of you once again who know me know that I push my stoves very hard to heat my old house. I do not over fire them but run them hard and they have delivered year after year of perfect performance. I run them on constant burn as the cycling annoy's me with room temp mode and it just is not practical for me with the recovery after shutdowns as shortly after it will re-fire.

So this leads me to ponder replacement parts and what I should get ? As of now the only replacement parts I have is an igniter and this makes me uncomfortable as this is my main source of heat and only source of heat in a power outage. I do have oil backup which I do not use ever except to heat water for the super store tank but do not have it setup to run in the case of a power outage, my pellet stoves will run off a generator in a power failure.

My thoughts on the parts which I will install and the existing will become backup parts to go on the shelf .
Convection and combustion motors and fans, Auger motor, and I am even considering a logic board replacement so that I have a backup on the shelf as well.

Your ideas on any other parts would be greatly appreciated and money is not a factor as I work my azz off and get paid well, it is time that I don't have currently and for the next year guaranteed. After that it will be back to work on the house and I have made it clear to my employers this is what has to happen in my life.

So for a better explanation running in constant burn mode I always run 4 feed rate except when it hits double digits below 0 I will crank it up to 5 . What use to be 4 setting runs like 2 now , 5 runs like 3 , 6 setting runs like 4 barely ect.....

Want to order up some parts right away to have backup parts in my possession before it starts to get cold but to have my stove running at its designed performance rate again . So far the only thing I have done to the stove is to replace the ESP probe , door gaskets both ash and main door .

Thanks in advance for your response.

 

Any snap switches on those? Vacuum switch.

As for falling performance, can't imagine it's any electronics, so besides the deep down cleaning, my suspects would be the exhaust blower, then the convection blower.

 

Have you replaced an auger motor recently? I believe some P68's use 4 RPM gearbox others use 6 RPM. Your output difference falls along this 2/3 rd ratio.

If not that I'd try a new ESP, always worth having a spare around anyways.

 

Just made me think about the possibility of the bolt/set screw holding the auger to the motor shaft being loose.....auger slipping???

 

Don't discount your fuel as being the culprit either....sometimes that GREAT pellet last year is only an OK pellet this year. That being said, a disclaimer:

Its difficult to diagnose a stove without seeing it and seeing quantitative measurements such as actual surface stove temp and magnahelic readings AT THE VAC SWITCH. Im sure you realize and understand this, but one of the most difficult, if not impossible, customer stove issues are the ones where the user states that "it just doesn't feel like its putting out enough heat...."....way too many variables there, some of which includes changes to the home and changes to the users health (blood thinners, blood circulation issues, and age tend to make it FEEL colder than it is, etc.), believe it or not.....

Embrace your OCD! Pretty sure its just a label created by those other lazy individuals who just don't understand (or care) what it takes to properly maintain your equipment and keep it at optimal efficiency......these tend to be the same folks who neglect their equipment, deep down realizing that issue, and not wanting to admit their fault, so, tend to normalize their neglect and call folks who take care of their things as OCD, and the more neglectful people (than themselves) are, well, lazy......but I digress....

I'm not a huge fan of just replacing parts to fix an issue. BUT I will concede that if in the wee hours of the night a part gives up the ghost, and you don't mind spending some money, that most dealers simply aren't open at 2am for you to drop by for parts. Not only that, but I don't know of any dealers who have emergency service and are going to come out to your place at 2am.....(besides, it would probably be cheaper for you to own the parts!).....so, here is a list of parts, in order of frequency of failure....one being the most common....
1. Flame Guide (only good for a few years AT BEST till it warps)
2. Circuit board fuse
3. ESP probe
4. Combustion fan AND impeller (don't cheap out now and just get the motor....get the impeller too!)
5. Circuit board
6. Feed motor
7. Distribution fan
8. Room sensing probe (or batteries for the remote probe if you have a TC unit!)
9. Vacuum switch

If you buy parts also, it would be a good idea to test their function PRIOR to needing them...its rare, but sometimes parts are faulty out of the box! Money-wise, if you bought all this, it would be fairly expensive, so, again, not advocating buying all these!

As for your stove, Luney, cant really tell you much without those draft readings. If you took readings when the stove was new, you'd have a baseline to compare current readings with, and that tends to tell you if there's a mechanical issue or cleaning issue. We take the readings when we install a new stove and write those readings in the user manual. We don't keep a record of everyone's readings, so, don't lose the manual!

I am sure your clean your exhaust, so thats likely not it, but what about air intake? If you have that, is the intake clear, or is there a bees nest, or leaves in there? Is the intake damper swinging freely or is it sticking? Just a couple thoughts!

 

Great Information Guys and I do REALLY appreciate you all spending the time responding with Excellent information. Forgot to mention I did replace the flame guide last year.
I will start checking different things starting with the easiest first but will be putting some serious thought into what parts I want to order , this has been a gradual degradation starting about mid-season last year.
Once again LW , Imacman and JZ thanks for your input its extremely valued and appreciated.

I would consider loading it up and taking it to a dealer but have always been self sufficient and have a hard time letting go of that. With that said I do respect their knowledge(respectable dealers) and would take it but loading that fricking beast is no easy chore and I definitely not the man I use to be and refuse on injuring myself again, shoulder still not right.

Thanks again Gents

 

Get it apart and look at all internal parts.

Have spare gaskets for the exhaust fan (Usually they go away during a fan removal)

Make sure the exhaust fan is running at full speed.
I am not familiar with this stove....does the exhaust blower require oiling ???
If so use a good high temp light viscosity oil.

Be sure the exhaust fan blades are clean.

Vent system clear ???
Get the hopper cleared and make sure the auger turns freely and that there is not and pellet residue clogging the area in the hopper where the pellets feed into the auger...or any other areas in the feed mechanism.

Remove auger motor and turn the auger by hand.

A tight auger will overwork the motor AND SLOW DOWN THE FEED RATE.

If auger is tight...get it out and find out WHY.

Make sure EVERY nook and cranny that can collect ash is cleaned out.

Leaf blower trick does wonders (DOOR OPEN)

 

The combustion fan isn't gasketed, and it doesn't require oil, nor are there any oil ports. The bearings are sealed. All the other stuff is GREAT advice, should be done, but its still guesswork. Not a huge fan of folks yanking the auger out. All you need to do is put it on TEST mode, time and count the revolutions for 30 secs....it should either be 3 complete rotations or 2 complete rotations in 30 secs (depends on the serial number, see post above from JZM).

Leaf blower trick is fine, but as Snowy Rivers mentioned above, be sure to open the front door first....damage could result to the vac switch otherwise.

 

Luney, I had a similar problem a few season ago. In my case it was fuel starvation that caused it, and it happened gradually over an extended period of time so it took a long time to identify there was an issue, much less the cause of it. There is about a 1 in a billion chance this is your issue as well, because the dealers told me I am the only person on planet earth that ever had this problem...but just in case you are #2, grab a bourbon and read this thread. If nothing else, it will give you some ideas on what to look at for potential issues.

Harman P68 Slow Startup

Edit: For spare parts, I keep:

1. Igniter (never needed so far)
2. Dist Fan (replaced last season - was 10 years old and getting loud, bearings shot)
3. Comb Fan (burned out, replaced in 2013)
4. CB fuses (replaced when comb fan burned out and ate a fuse)
5. Auger motor (replaced a few seasons ago, troubleshooting the slow startup issue - wasn't bad)
6. ESP probe (never needed so far)

 

Hey Lowsey. If he had a Harman DDM would that help.

 

Always did mine w/ vac switch disconnected. Closing the door completely = better suction/more ash removed.

Also, LW, does the auger have a set screw/bolt holding it to auger motor? Ever seen one loosen up/slip? Seen it on other stoves....friend back in NY couldn't figure out why such small amount of pellets, even on high feed rate.

 

I would agree 100%...but, if the auger is not turning free it could be causing a heavy load on the motor that is varying with time, heating of the internal parts etc.

Just want to be sure that there is not a fly in the ointment anywhere.

 

not really.....it wont give you things like draft, etc....it is helpful in seeing what temp the ESP *THINKS* its reading, but other than that, not hugely helpful with issues where the stove "doesnt seem to be heating well enough"

 

yup, Ive seen loose bolts which break the connection between the auger shaft and gearmotor...usually its after someone pulls out the auger or replaces the gearmotor. If they dont tighten sufficiently, or dont get the end of the bolt to seat on the flat part of the auger shaft, it will slip.

 

Please check that feeder pivot bushings are lubed and operate freely. Seen those bound up before which can slow auger down.

Also check that feeder arm is riding on auger roller. Seen a case where it wasn't and feeder was being short stroked so feed rate was very low.

 

Hello
I actually believe that open frame exhaust blowers that Harman use, that do not have oil ports like the closed frame blowers that Whitfield and other stoves use can actually benefit by oiling because applying oil to the input shaft that is extrudes beyond the seal does allow oil to seap in and lubricate. This application has quieted noisy blowers in my experience. I have also seen MDS sheets on these pellet blowers that do in fact specify and recommend light weight machine oil and I use and highly recommend Anderol 465 synthetic bearing oil that Dr . Whitfield recommends for his blowers.
I also have talked to an Engineer who works in the manufacturing plant about the exhaust blowers they make for Harman stoves about what the leading cause of failure of these blowers when I was researching the differences in longevity from one pellet stove to another. The main cause is heat and I found from taking thermal measurements a range of difference in the heat build up around these motors from one type of stove to another.
I can get a professional engineering statement about lubrication if needed but he may concur that additional lubrication each year will help replenish the original lubrication that is lost from the heat and normal usage of the exhaust blower.
Just my experience. See pics below.

 

LOL. Fuel quality can be a problem. But in a p68 make sure all gaskets are fine,and replace the exhaust probe.They can and do go out of range,but cheap to replace.just my 2 cents worth.

 

Have been able to run the stove a bit with the cooler weather and am observing its operation. The stove is clean as always , the fuel is good if not great seems to be more of issue with it not cycling long enough or often enough to maintain the standard flame for the respective settings. I did order a new ESP first but back to working insane hours again and if the ESP does not improve the performance then I will start to order the other items. The existing one is less than a year old but as Bob the cheapest part to start with and anything can suddenly go batty.

 

Interesting
Thanks Don
Seems everything is operating as it should just does not continue long enough for the desired performance, Ill start with a new ESP and move from there as I don't have any backup parts on the shelf and would rather have them there then have to depend on a shop being open.

 

All good information Guys thank you kindly, just have to find the time to apply some of this information (5 am to 6 pm today Sunday bah but on the brighter side am getting paid for it even though I am on salary negotiation negotiation negotiation ! )