Harman Accentra Insert Distribution Fan

[F4jock]

I'very had my insert for five or six years and understand it pretty well. I know how the ESP works, the various modes etc. BUT I'm not sure what triggers the disttibution fan. Is it temperature controlled by an internal switch? Is it tied into the ESP somehow? Is it controlled by the room temperature sensor? (I operate in room temperature mode.) Thanks in advance for any help you can offer.

 

[Delta-T]

its connected to the ESP probe. Most Harmans will kick the fan on at around 135-145 deg....assuming the ESP is clean and working correctly.

 

[F4jock]

its connected to the ESP probe. Most Harmans will kick the fan on at around 135-145 deg....assuming the ESP is clean and working correctly.

Interesting. Thanks. I see the logic but to my way of thinking it'd be more efficient if it was connected to a separate thermocouple in the blower ductwork allowing the blower to run longer. This would use more of the latent heat and satisfy the room temp faster thus saving fuel.

 

[Tim_M]

I too am a bit confused about what regulates the distribution blower on my recently installed Accentra insert. The speed seems to vary, from low and barely audible to high and a bit loud, based on the room temperature the probe is reading. But if that's true, what does the fan speed control do?

 

[F4jock]

I too am a bit confused about what regulates the distribution blower on my recently installed Accentra insert. The speed seems to vary, from low and barely audible to high and a bit loud, based on the room temperature the probe is reading. But if that's true, what does the fan speed control do?

I THINK it's a combination top speed limiter and fan activation vs temp control but that's empirical by observation in room temp mode. No hard copy to back it up.

 

[smwilliamson]

I'very had my insert for five or six years and understand it pretty well. I know how the ESP works, the various modes etc. BUT I'm not sure what triggers the disttibution fan. Is it temperature controlled by an internal switch? Is it tied into the ESP somehow? Is it controlled by the room temperature sensor? (I operate in room temperature mode.) Thanks in advance for any help you can offer.

ESP reads 174-185 degrees and kicks out the igniter power and starts the fan

 

[F4jock]

ESP reads 174-185 degrees and kicks out the igniter power and starts the fan

Yep but what starts / stops it during normal operation when the inigter is off?

 

[smwilliamson]

Nothing. Except maybe you or any foreign object that falls down into it. When you are in run mode it's on, full time. You can adjust the velocity by sweeping the mode knob from L to H but the motor only shuts off when the esp falls back down to 95 degrees.

 

[F4jock]

Nothing. Except maybe you or any foreign object that falls down into it. When you are in run mode it's on, full time. You can adjust the velocity by sweeping the mode knob from L to H but the motor only shuts off when the esp falls back down to 95 degrees.

 

[F4jock]

Which in some cases happens often. My fan seems to cycle about once a minute, running for about thirty seconds when room temperature is satisfied.

 

[smwilliamson]

You may need a new blower thenthen

 

[dhall28]

this may not be so on your stove, but some people get a bunch of pet hair and dust sucked up underneath the stove where the dist. blower is blocking off the cooling vents to the motor, the motor will run at first and then start cycling on and off periodically as the thermal breaker inside the blower motor cycles.

 

[F4jock]

this may not be so on your stove, but some people get a bunch of pet hair and dust sucked up underneath the stove where the dist. blower is blocking off the cooling vents to the motor, the motor will run at first and then start cycling on and off periodically as the thermal breaker inside the blower motor cycles.

Not the case. The blower runs constantly at night when the temperature drops and the stove feeds heavily. My take is that there is some link between room temp, ESP temp and blower function such that the blower cycles off when temp is satisfied. My guess that it is somehow delta-t dependent.

 

[dhall28]

in order of decision making there is the ESP, the room probe and the speed selection. The stove will try to run at the fan speed you select but will shut off if the room temp is met or esp drops below a set low limit, or will totally override the speed setting going to high if the ESP climbs above a set high limit temp. the room probe will tell the stove if the room is satisfied or not turning on or off the fan, but the overriding factor is the ESP which will not let the fan come on if it is below a set low limit so it can know when to turn off while shutting down, on the other hand no matter what anything else is saying if the ESP is above a set temp it will turn the fan on (high speed), even if the stove is in OFF mode or set to L speed fan, so yes the numbers may be slightly different depending on board number/revisions and stove model and what mode you run the stove in but ultimately it does come back to what the ESP says with the room temp and speed selector having some effect part of the time

 

[F4jock]

in order of decision making there is the ESP, the room probe and the speed selection. The stove will try to run at the fan speed you select but will shut off if the room temp is met or esp drops below a set low limit, or will totally override the speed setting going to high if the ESP climbs above a set high limit temp. the room probe will tell the stove if the room is satisfied or not turning on or off the fan, but the overriding factor is the ESP which will not let the fan come on if it is below a set low limit so it can know when to turn off while shutting down, on the other hand no matter what anything else is saying if the ESP is above a set temp it will turn the fan on (high speed), even if the stove is in OFF mode or set to L speed fan, so yes the numbers may be slightly different depending on board number/revisions and stove model and what mode you run the stove in but ultimately it does come back to what the ESP says with the room temp and speed selector having some effect part of the time

Appreciate the explanation. Thanks!

 

[dhall28]

no problem, harmans have a some what complicated logic programmed into their control boards but it keeps their wiring simple, which I like.

 

[skipp025atyahoo]

I'very had my insert for five or six years and understand it pretty well. I know how the ESP works, the various modes etc. BUT I'm not sure what triggers the disttibution fan. Is it temperature controlled by an internal switch? Is it tied into the ESP somehow? Is it controlled by the room temperature sensor? (I operate in room temperature mode.) Thanks in advance for any help you can offer.

The distribution blower is controlled only by the (micro controller) computer board. But the computer determines
everything about how the distribution blower should operate as part of the overall information provided by other
input devices, which include the ESP (probe), knob settings, switches and sensors.

Based on my recent experience trouble shooting an Accentra insert, I'll suggest the distribution blower, although
directly controlled by the micro computer board, does primarily rely on the temperature value input from the ESP,
the control knob settings (values) and the software running in the micro controller. Things/values like the hopper
door and internal pressure sensor don't seem to be part of the "algorithm" (computer program) affecting the
distribution blower speed.

In the real world, the distribution blower should run at any speed within its normal range, without making excessive
bearing noise or drawing excessive current. Some blowers just by the nature of their design, construction and
operation do make a fair amount of physical air noise when they operate. I have one running across the room
at full speed and the blower and air noise is well worth the ongoing heat exchange.

So in regards to the distribution blower, you're primarily concerned that it does come on, doesn't make a bad
mechanical noise and its motor current draw is within the nominal value.

If the distribution blower in operation seems unpredictable, that part of the equation is probably acted on solely
by the micro controller (computer) and the values provided to it by the ESP and room/stove temperature
sensors. If you experience what you might feel are suspected problems with the distribution blower, not
related to some of the issues I mention above, one key to trouble shooting the problem is the speed at
which or when the problems start occurring, as an example from a completely off or cold start and the
room temp when you start the stove.

If you are having a problem, you might describe it in more detail here and I'll try to suggest some trouble shooting
tips for you.

cheers,

skipp

skipp025 at yahoo dot com

 

[No worrys]

Hi new to the forum,
(Accerntra insert)
I'm in need of help with distribution blower not coming on! Just last night the blower stopped working. I tried every thing I know to get it to start blowing. But had no luck. Did a full cleaning ,ESP,fans, everything. Not sure what else to do.
Please if any one HELP...

Thank you...

 

[Bioburner]

Is the fan getting power and running when you put the stove in test mode? How old of unit? Might have some warranty left? Motors take a bit more of a beating in inserts with dust bunnies and heat.

 

[skipp025atyahoo]

Hi new to the forum,
(Accerntra insert)
I'm in need of help with distribution blower not coming on! Just last night the blower stopped working. I tried every thing I know to get it to start blowing. But had no luck. Did a full cleaning ,ESP,fans, everything. Not sure what else to do.
Please if any one HELP...

Thank you...

With the stove operating, look for the LED displays to indicate everything is operating
correctly. If the combustion LED doesn't light the distribution blower is probably not
working (detecting the heat value). Replace the ESP probe and clean the inside of
the stove out real well.

good luck

skipp

(still here after all these years).

PS In case any of you read my previous trouble shooting stories, my Harman Accentra
is still working well although I have never changed out the crappy igniter after the last one
failed.

Another follow up comment... Once bad short coming of the stove design is the micro controller
receiving primary heat/temp information from the ESP thermo-couple. If the ESP fails while the stove
is in full on heating operation, as mine did... the stove stops the distribution blower and a potentially
dangerous over temp condition results. I was fortunate to be watching mine when the ESP
failed, causing the over-temp situation to start. A good design will have a back up detector
just to prevent this type of situation from happening... I'm surprised Harman hasn't had anyone
else complain about this horrible liability issue, it being so badly ignored.

I don't leave the house with my Accentra operating...

 

[No worrys]

With the stove operating, look for the LED displays to indicate everything is operating
correctly. If the combustion LED doesn't light the distribution blower is probably not
working (detecting the heat value). Replace the ESP probe and clean the inside of
the stove out real well.

good luck

skipp

(still here after all these years).

PS In case any of you read my previous trouble shooting stories, my Harman Accentra
is still working well although I have never changed out the crappy igniter after the last one
failed.

Another follow up comment... Once bad short coming of the stove design is the micro controller
receiving primary heat/temp information from the ESP thermo-couple. If the ESP fails while the stove
is in full on heating operation, as mine did... the stove stops the distribution blower and a potentially
dangerous over temp condition results. I was fortunate to be watching mine when the ESP
failed, causing the over-temp situation to start. A good design will have a back up detector
just to prevent this type of situation from happening... I'm surprised Harman hasn't had anyone
else complain about this horrible liability issue, it being so badly ignored.

I don't leave the house with my Accentra operating...

Thanks Skipp,

All lights are lit up. No airflow out.

 

[smwilliamson]

Sounds like the blower is junk. It should come on during test mode. Don't pay $300 for a dealer blower either....look up Fasco B47120 on the internets. Connect black and white wires only, tape off red and blue. The threaded grounding post on the bottom will need to be snipped off about 1/8" after the green wire is attached....but this blower IS the same blower as the Harman OEM with the modifications I've just layed out.

 

[jmcvinnie]

Great information on the replacement Fasco blower, found one for $92. I own a 10 year old Accentra insert which I expect the blower could fail at anytime. Anymore tips on replacement parts would be appreciated. Thanks

 

[corkman]

How does one access the distribution blower. I just picked up a 2004 insert on the cheap and want to remove the distribution blower go clean. I have no idea on how to get at it

 

[smwilliamson]

Pull the stove out and tip it forward, rest it on a pellet bag and don't bend the door handle