Air intake versus exhaust blower voltage

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Brokk

Member
Dec 9, 2008
126
Central/Eastern Mass
I gave up on my old PelPro 120 (2008 model) and just bought/installed a Comfortbilt HP22N. It has a nice controller that allows you to tweak many of the settings. One of them happens to be the exhaust voltage.

My Pelpro seemed to suffer from too much combustion air. This HP22N was the same way on the first start. Changing the air intake is the easiest and recommended way to reduce the combustion air. However, even with it closed as far as it is allowed, the 1/2 burned pellets are still jumping around too much IMO. So I turned the voltage down and things got better.

My question is this... Is it better to open the air intake *and* reduce voltage to get the right amount of combustion airflow, or is it better to reduce the air intake as far as possible while maintaining the highest voltage that has the right amount of airflow?

There must be some value, or balance point to how the two interact. I figure the vacuum will be much higher in the second case (high V, low air intake) and the exhaust fan will be working much harder. Not sure if that is the best scenario. (no, I haven't hooked up my gauge for the pressure yet)
 

SidecarFlip

Minister of Fire
Feb 7, 2010
5,273
S.E. Michigan
If the combustion blower has a shaded pole motor (99% do), you aren't reducing the voltage, you are chopping the dwell time via the Triac and the circuitry. How they work.
 

Brokk

Member
Dec 9, 2008
126
Central/Eastern Mass
If the combustion blower has a shaded pole motor (99% do), you aren't reducing the voltage, you are chopping the dwell time via the Triac and the circuitry. How they work.
(shrug)

I'm using the terminology they use in the manual and menu settings. Interpret it how you will. The effect of lowering the pull of the exhaust blower still happens. Either way, my question still stands.

Assuming one achieves the desired airflow for the flames/burn, is it better to have less voltage and more air intake, or more voltage and less air intake?
 

tlc1976

Minister of Fire
Oct 7, 2012
966
Northwest Lower Michigan
I would set it so you don’t have to keep changing the damper when changing heat ranges. So you can let the stove remain automated, keeping optimal air flow at all settings. So it sounds like you set it well.

But if you need to vary the damper because you need more range than the controls offer, then do that, it’s always better to have an optimal burn. I have to do that on mine.

Running the blower on full and throttling the damper instead seems to give more control in iffy conditions. Like if strong winds sometimes blow the fire out when running on low. Otherwise I think you’re just using more energy to unnecessarily run the motor faster. But it’s probably barely noticeable.
 

SidecarFlip

Minister of Fire
Feb 7, 2010
5,273
S.E. Michigan
(shrug)

I'm using the terminology they use in the manual and menu settings. Interpret it how you will. The effect of lowering the pull of the exhaust blower still happens. Either way, my question still stands.

Assuming one achieves the desired airflow for the flames/burn, is it better to have less voltage and more air intake, or more voltage and less air intake?
All I did was tell you the principles of operation, nothing more. Don't care what the 'manual says' it's written to be generic. I will say at least you read it. Most don't.
 

JRemington

Minister of Fire
Nov 4, 2017
711
Belleville New York
I gave up on my old PelPro 120 (2008 model) and just bought/installed a Comfortbilt HP22N. It has a nice controller that allows you to tweak many of the settings. One of them happens to be the exhaust voltage.

My Pelpro seemed to suffer from too much combustion air. This HP22N was the same way on the first start. Changing the air intake is the easiest and recommended way to reduce the combustion air. However, even with it closed as far as it is allowed, the 1/2 burned pellets are still jumping around too much IMO. So I turned the voltage down and things got better.

My question is this... Is it better to open the air intake *and* reduce voltage to get the right amount of combustion airflow, or is it better to reduce the air intake as far as possible while maintaining the highest voltage that has the right amount of airflow?

There must be some value, or balance point to how the two interact. I figure the vacuum will be much higher in the second case (high V, low air intake) and the exhaust fan will be working much harder. Not sure if that is the best scenario. (no, I haven't hooked up my gauge for the pressure yet)
There’s nothing wrong with the pellets bouncing in the pot after they are burned. What are your settings on stalls one through five?
 
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Emich

New Member
Jan 5, 2022
5
Emich323
I gave up on my old PelPro 120 (2008 model) and just bought/installed a Comfortbilt HP22N. It has a nice controller that allows you to tweak many of the settings. One of them happens to be the exhaust voltage.

My Pelpro seemed to suffer from too much combustion air. This HP22N was the same way on the first start. Changing the air intake is the easiest and recommended way to reduce the combustion air. However, even with it closed as far as it is allowed, the 1/2 burned pellets are still jumping around too much IMO. So I turned the voltage down and things got better.

My question is this... Is it better to open the air intake *and* reduce voltage to get the right amount of combustion airflow, or is it better to reduce the air intake as far as possible while maintaining the highest voltage that has the right amount of airflow?

There must be some value, or balance point to how the two interact. I figure the vacuum will be much higher in the second case (high V, low air intake) and the exhaust fan will be working much harder. Not sure if that is the best scenario. (no, I haven't hooked up my gauge for the pressure yet)
blocking the air intake by %75 on my pellet stove increased the output air temperature from 110 to 150 degree without any other changes.
I have Winslow PS40. There is no dumper.