Harman invincible RS questions

Hey guys, I have had my Harman invincible RS for about 3 years now. I have always burned on stove temp and at level 4ish with temp setting mid range to high. And feed rate just below 3. That produced a good strong flame and kept the inch of ash in front of the burning pellets. Two days ago our combustion blower crapped out. I have cleaned this stove each year, but never really dove into the mechanics of it. I removed the combustion motor and fan blades (two single blades), went to my local parts counter and got a new replacement motor, and the guy asked if it was twin blade, so I said yes. He handed me the new style 5 inch double paddle blade, I had read about the awesome low draft these had and didn't think twice. Took it home, installed it and lit the fire. After I shut the door, the initial flame seemed much weaker, and it took a little longer to heat up...but when it did...holy smoke, the feed motor kicked on repeatedly and the flames were curling over the front door, even after I turned the feed rate to 1 and the stove temp to 60 it just kept running, and coated my windows black inside. Long story I know...but what's going on? It was like a run away diesel engine...running hot and heavy, and overflowing the burn pot. Is this something I just need to mess with because of the new fan blade? Or is something else a miss?

Thanks guys

Bioburner said:

Did you also clean the ESP in the exhaust path?

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That is the probe in the exhaust pipe correct?

Bioburner said:

It's in the stove yet, right before the venting adapter. If that vital part is covered in heavy ash or worse yet damaged, it throws the stoves brains into a tail spin as the board controls feed and fans by the temps its sensing by the probe. They do fail after many hot cold cycles also. About a $70 part.

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OK. I pulled that this morning, and cleaned it off. It did have a good amount of soot on it. I don't think it has failed, like I said I haven't done anything besides install the new blower and those different blades. It worked great Wednesday, then the blower conked out. I also got a wild hair and pulled all the panels and cleaned the stove out completely...just to make sure I have got air flow

bags said:

Cleaning the ESP will help IF it is still good. If your stove still continues to run crazy then the ESP might be bad. They don't fall apart or break necessarily when they go bad.

How's it running after the clean?

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Its still a very lazy flame. When I lite the pellets the flame hardly changes, before with the two fan blades it would blow like someone was pushing compressed air through it.

Oh and it sounds like the motor slows down after a few minutes of blowing air.

bags said:

I am not sure but my PC45 has the single fan blade and the new P68 has the doubled front and back fins. Why didn't you replace it with the single that was like the original? It might be that the double is pulling more air out and starving the pot and fire a bit. Not sure. Are your door gaskets old and worn? Have they been replaced? Do the dollar bill test and shut the door on one all around. If they are good ropes then it should be tight and harder to pull out. Others run a lighter around them to see if the flame gets pulled in.

It could be that your ESP has seen a better day also. The ESP seems to be a major culprit of erratic burning and such. I'd guesstimate the door gaskets and/or the ESP need help. Try fluffing the ropes up by squeezing them some first.

Bioburner is the guy you .

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is had two single blades on the motor shaft. I told the guy at the parts counter that and he handed me this twin paddle, I guess I didn't know any better. Bill test is good the gaskets are all soft and the door shuts firm. Guess its back to the store tomorrow. Just wanted to get this fixed today...-35 wind chill tonight

bags said:

Likely your ESP. Get one and try it. That is a prime part in the Harmans system and good to have as a stocked back up on hand. I am not really sure the twin blades would have any negative effect. Many upgrade the older models with newer parts too. Not sure if any dip switches need to be changed to accommodate the upgraded blower fans.

Do you know when or if the ESP has ever been replaced? I know the Invincibles are older models. There are several here with them so hopefully they chime in. Good Luck!

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I have never replaced it. And the people that had it before us never used it, some I'm assuming that it is the original ESP

Tim_M said:

is is possible to remove the old fan blades from the old motor, clean them up and then put them on the new motor? Might be worth a try.

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Unfortunately no, they were seized on the shaft and quite corroded.

Bioburner said:

Sometimes stove repair ends up like a string of dominos especially when working with older units. Hope the stove is on a good surge suppressor or UPS. If you haven't yet, get the room fan out and clean off the fins and blow out the windings to prevent dust bunnies from killing that motor too. Now another issue may be the pot switches on the control board. I am running a ten year old board in our PC45 from another stove and when I touched the switch it changed the exhaust fan speed. Problem started yesterday so that board is due for new switches and glad have a spare as its only 3F out.

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I took the room fan out, and cleaned and oiled the bearings. It just seems odd that this stuff has gone wrong when all I did was change the combustion fan! Lol I hope I can get it figured out tomorrow.

English BoB said:

Go back to the original combustion blower. Its the only thing that you changed.

Bob

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I would love to...but that one died, that's why I had to get a new one

Tim_M said:

The original combustion fan on my '93 Invincible T is still going strong, but I just got a replacement off Amazon to have on hand as a backup. There was a thread on here a few weeks ago about the Fasco replacement having a slightly smaller diameter blade than the original (4.75" vs 5"), that caused the poster's Invincible to run poorly until he replaced it with a 5" one. I think I will do the same with my backup unit. I see there are a few places online where they can be ordered, for as low as $15.
Could the blade on your new fan be slightly under-sized compared to the original?

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As far as I can tell it is a true 5" blade. Hearth and Home Technologies 5in Double Paddle Blade #3-20-502221

OK guys problem solved!

Had a tech come to the house. Took one look at the blower fins on the top of the blower...drafting the wrong way! Came from the factory reversed, took the top fan off, cage off, and flipped the coil over. Now it runs great!

I included a pic of the part number and date of manufacture just in case this happened to someone else.


Thanks for all your help guys.