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Harmon P68 Sensor Control

Posted by jaa52 (jaa52@banet.net) on
Thu, Nov 3, 05 at 14:56

I have probably beaten this one to death but here we go I set the temp control to 70 on the stove, I have a thermometor 6 inches away from the end of the sensor. The thermometor reads 67.0 to 67.5 and the stove finally turns on. Now the stove runs. I walk out in the morning and hear the stove running and look at the thermometor and it reads 73.5 degrees. The temp control is still set at 70 degrees and the stove is still running. The dealer called me back today and we spoke. She said this was not the first call she received concerning this issue. I was told that the temp control and the sensor are not an exact science. So I can now assume thats it I guess? Any ideas, experiences with this problem and a solutions?


Follow-Up Postings:

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RE: Harmon P68 Sensor Control

I will have to get a thermometer and test my sensor out. I don't think it is that accurate. Seems like they could either get it right or make it so you can hook up a thermostat.


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RE: Harmon P68 Sensor Control

Well let me know I believe I proved it is inaccurate but let me know, hope we get more responses about this.


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RE: Harmon P68 Sensor Control

I got the Harman xxv pellet stove and I think the book on it is very basic too. I also think a lot of heat is going out the vent pipe, when I put my hand near it, it was very warm (out side) did anyone else every check this out? Like some one said the web site for Harman sucks, no answers for so many questions.


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RE: Harmon P68 Sensor Control

A simple forum on the Harmon site for customers would be great, rather then leave a message at the dealer. For what we pay for this product a quick response is really not looking for much. I do not believe there is an email address to send a note to Harmon on their WEB page or phone number. I did find their phone number somewhere else but understand they refer you to the dealer.


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RE: Harmon P68 Sensor Control

I bought my harmon P68 a year ago October. Last winter I had issues with the thermocouple that reads or senses the temp. Just about every morning that I got up, the temp would vary 3-5 degrees. I had it set around 70 and when I woke up, the house would be as cool as 65. I found it is easier to set my stove on stove temp, I usually set the temp around 2-2.5 and the feed speed between 2 & 3. I found that I use less pellets and the house is warmer. I know it's not recommended to set the feed speed to low, but it seems to be working just fine for me. With my stove on stove temp and not room temp, I use about 1/2 bag less every twenty four hours. I think Harmon makes an awesome stove, but their website and their people skills could use some work. You would think that they would want to interact with their customers, but I get the impression that they don't want to be bothered.


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RE: Harmon P68 Sensor Control

Bingo, we see the same thing my stove has been set at 70 the thermometer placed in the same room 3 feet away reads 65 degrees. I hate to jack up. On the other end when its set at 70 and does come on it runs and my room is 75 degrees. So 65 to around 75 degrees diffenece will use alot of pellets to make up 10 degrees I now believe the probe does not work as sold. Even my dealer admitted it was not a perfect sicence, tell me more about stove mode do you get enough heat at those settings? Did you call Harmon direct and get the cold shoulder?


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RE: Harmon P68 Sensor Control

The problem with "Stove Mode" is it will always maintain that temp. and therefore you will lose efficencey. The stove is no longer going up and down in temp to keep an average temp. in the room....(like it is advertised to do ) it is just maintaining an average stove temp. This is how I had to run my stove ever since I hooked up outside combustion air and keep getting smoke in my pellet hopper, it is alot less efficent, but I didn't have much of a choice, so now I just run my furnace when I'm not home, much less efficent, but atleast I don't have to worry about my house burning down !!!!


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RE: Harmon P68 Sensor Control

I have had pretty good luck running mine in Stove Mode. It doesn't appear to use more pellets, it actually seems to use less. When your stove is running in "room temp mode" it is still feeding pellets, maintaining a small fire. Mainly just the blower shuts off. I think it's personal preferance, I would rather have the unit blowing a constant heat if it is using pellets. Where do you guys live. I am in central NY, temp gets pretty cold around here. I live in a Ranch and I have my stove in the basement. Half of the basement is finished off, so I have an open stair case going into my living room and kitchen. Last year I burned approximatly 2 bags a day with the P68. It kept my home nice and warm, but I thought I used quite a bit in fuel. I am heating about 2000 square feet. Do you guys use that much?

I put the outside air kit on my stove last winter as well. I have not had any issues with smoke coming up through the hopper. If the power goes out, my unit will smoke between the hopper and the stove. I complained to my sales person and he offered to refund me my money because he did tell me that the stove wouldn't smoke. I opted for the battery back up unit at cost in lou of returning the stove.

I don't understand the feed rates and all that stuff. It is trial and error. My assumption is if your stove feed rate is set at 3, then your stove is feeding approximatly 3 pounds of pellets an hour. I don't know that for sure, but I am assuming that's what it is doing. I am trying to figure out how the temp dial comes into play, if you are set at a stove temp of 4 does the stove automatically adjust the feed rate to achieve that temp of 4? If anyone has any answers, I would love to hear them.

Jaa52, I wish I had the answers you were looking for. I don't think the thermocouple is all that Harmon made it out to be, I would suggest moving it. I beleive you can run it up to 25' away from your stove. Maybe you would have better luck with that.

I did contact Harmon once, I went to their website, there is a link at the bottom of each page.... comments about our site.... I typed a very nasty letter to them using that link. A rep from harman did call me after I did this. If more poeple do this, maybe Harman will get the point and start offering real support.


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RE: Harmon P68 Sensor Control

Thanks, so incosistant the sensor.Another example of the sensor being of is this morning it was warm here in Hanover Massachusetts, my stove is set to roughly 70 71 and the living room is 75.6 on my thermometer and the stove is running wasting fuel, what gives with that? I turned the dial down just a hair and the stove began its normal slow down shut down mode. Conclusion off 3 to 4 degrees either way up or down.


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RE: Harmon P68 Sensor Control

My dealer said to keep the feed rate at 3 which is where it is set at. That is a good question regarding the feed rate and the stove temp setting. Don't know the answer. I will ask the dealer if he ever calls me back. Had 25 bags of pellets that were ruined because water got in. Called twice to get them picked up but no return call yet. I am using about a bag a day in southern vermont now but its not very cold out. I imagine it will be two bags a day soon. I think the esp control stands for Essentially Sloppy Performance but I am not sure. I will have to ask the dealer about that too.


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RE: Harmon P68 Sensor Control

Are you not happy with the performance of the stove? I am looking at stove mode also, keep us posted when they finally call you


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RE: Harmon P68 Sensor Control

The stove works fine and I can get the sensor to work fairly accurately by moving it around. There are times when I think the stove should be coming on and it isn't and other times it is running when I feel it should stop. I think the probe is described to give an impression that it is more accurate than it really is. I bought the stove to burn as little oil as possible and I am very pleased with it.


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RE: Harmon P68 Sensor Control

Rick, I commented that my dealer admitted to the sensor not being 100 percent accurate in his opinion, what does your dealer say about it? Any feed back also about the feed rate and stove temp setting?


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RE: Harmon P68 Sensor Control

Just this past Tuesday I had a P68 installed. I haven't had much time since to play around with diff. settings, but I have found out, using the stove on "room mode/ auto" it does seem to start to shut down pretty quick. It really puts out the heat, and it seems to really eat the pellets. My dealer said to set the feed at 3 1/2, I have at 3 now. John it seems I do have an airwash problem too, around the top sides of the door. My dealer instructed me to scrape the burn pot daily, once in the morning & once at night &wipe the glass with a paper towel. What settings & temp. have you guys been using? I bought mine hoping I would not have to run my oil furnace and so far, (its in the 20's)it does seem to be working OK. I don't have any hot air heat runs to my 2nd. floor I am thinking about cutting some vents in my ceiling to get the air moving better, I think that will help. I want to ask my dealer some things and I will let you guys know of anything. Ray


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RE: Harmon P68 Sensor Control

During the day when I'm not home, I run my stove on manual, "room temp mode". I have to do this for my battery backup. You can't allow the stove to shutdowm and restart off of the battery if the power were to go out. When I'm home at night and on the weekend, I run mine in Stove Temp mode. I usually set the feed speed between 2 & 3 and the temp dial at 3. This will keep my house around 72 degrees. It was 23 degrees outside this morning and the house was about 72. I think I use less pellets in stove temp than in room temp mode. I have run my stove in room temp mode as low as 2 for the feed speed and 2 for the temp and it runs fine. I use these settings when the outside temp is around 40. I hope this helps.


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RE: Harmon P68 Sensor Control

I have a P-68 and run in automatic "room temp mode". My control is set to 75 and the temperature runs perfectly between 74-75 degrees (we're old). The feed rate is set to 4, as the manual suggests. Never messed with that setting.

The house is well insulated, I use the fresh air intake, and my sensor is installed 18' accross the room, right next to the oil furnace thermostat so it's easy to keep an eye on the temp. I burn *no* oil, in fact the oil emergency switch is off, and that's the way it will stay. I made my own battery backup system so it will not be shutting down.
This is my third pellet stove over the years, and the absolute best so far.
Dave


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RE: Harmon P68 Sensor Control

Things you need to remember when installing the room sensing probe. The location of the sensor, this is a very important part of getting proper readings. If the sensor is located on the floor it will be measuring the temps from the floor (which is always colder) then your thermostat located 5' from the floor and across the room. dorcutt hit the nail on the head with his installation. They have their probe located directly beside their thermostat. This will be the most accurate way of getting a reading to the unit.

Also remember that when setting the feed rate to a low you are not actually "saving" fuel. This is actually tying the the stoves hands behind its back so to speak as for the amount of fuels it feeds in a 60 second cycle. This will cause the unit to feed more often rather then less often. The unit is trying to meet the temp that you set but can't because you limited the amount of fuel the unit feeds at any given time. Setting the feed rate at 4 allows the unit to push more fuel in the burn causing the temp to rise quicker allowing the unit to go back down to a maintenance feed (7 seconds every minute) once the set temperature is satisfied. Once the temp then drops to a certain degree then it will feed once again to the setting you have it at. The lower the feed rate the less it will feed when it calls for heat not allowing the unit to come up to temperature as quickly due to the lack of fuel in the burn pot.

hope this helps everyone a little.


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RE: Harmon P68 Sensor Control

I am interested in Dorcutt's comments about making his own battery backup. Can you elaborate on that.

Thanks,

Paul


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RE: Harmon P68 Sensor Control

My dealer told me to set it on 3. One of the sales people told me they have people set it at 2.5 if they are using too much fuel. I have been using at 3 but when its real cold I put it on 4. There is a big difference in the temp coming out of the stove when on 4 vs 3. I will have to experiment. What tsco29 says makes sense to me. thanks


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RE: Harmon P68 Sensor Control

let me know how it works out for you.


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RE: Harmon P68 Sensor Control

tsco29, what you have said makes a lot of sense, I was turning my feed rate down to try and save fuel. I have been running my P68 in Stove temp (auto), usually around 70 at 3 on the feed rate. Has been really cold here in Central PA, it seems to be working good. I want to try using the thermostat wire just haven't had time to make it longer.


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RE: Harmon P68 Sensor Control

pbs1011 asked (way back in Dec of '05)

>>I am interested in Dorcutt's comments about making his own battery backup. Can you elaborate on that.

I can't believe I missed that. I thought I had answered the question but that was on the Yahoo pellet stove forum.

Maybe someone else wants to make their own battery backup?
Mine is on a table in my cellar. It consists of:
Tripplite APS750 Charger/inverter
2 Deep-cycle marine batteries (WalMart)
12-3 Romex from the charger/inverter to a special wall outlet just for the stove.

The Tripplite was just over $200. The batteries between 50-60 each. This provides 750 watts continuous, or 1200 watts surge. My Harman P68 takes a maxium of 450 watts in auto start mode, and runs around 90 watts after that.

Sure, you can buy one from Harman or other places (Surefire?), but you won't find one with this kind of power for double the price (including batteries). Mine is on a table in my cellar. It's not the type of thing you would put in the living room.


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RE: Harmon P68 Sensor Control

Im still experiementing with the p61 but it does seem to read higher on my thermometer then whichever mode I use. Does anyone have an outside air source, and if so, any moisture problems on the incoming piping? Mine is lousy with condensation, to the point it leaves a small puddle on the floor. Anyone else experienced this? Thank you.


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RE: Harmon P68 Sensor Control

Has anyone hooked a programmable thermostat up to a P68? I had a Whitfield stove hooked up to one for the past 3 years and it has worked flawlessly. I just installed a P68 and would love to have it operate off the thermostat. Thanks


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