Speed Control of Combustion Fan???

 
User avatar
coalkirk
Member
Posts: 5185
Joined: Wed. May. 17, 2006 8:12 pm
Location: Forest Hill MD
Stoker Coal Boiler: 1981 EFM DF520 retired
Hand Fed Coal Stove: Jotul 507 on standby
Coal Size/Type: Lehigh anthracite/rice coal

Post by coalkirk » Wed. Feb. 18, 2015 4:23 pm

Staylo wrote:
coalkirk wrote:Do you have a radon mitigation system installed? It's a pretty simple thing to do.
Yes, we had a system put in at the same time I rigged up the fresh air intake for the Stoker. Our original test levels were over 90, and the action level recommended by the government is 4. After the system was put in and the fresh air intake was installed the subsequent retest gave a reading of less than 1. So I can't say for certain how much of that result is due to the fresh air intake as opposed to the mitigation system, but between the two of them they took care of the problem. And it is kind of nice not to be sucking my warm air I just heated out of the house and blowing it up the chimney just to heat more cold air I just sucked in from outside. :)
I can tell you. 99% is from the mitigation system. A reading of 90 is quite high so you must have a powerful radon fan.

 
RFK
Member
Posts: 35
Joined: Wed. Jan. 21, 2015 9:37 pm
Location: Perry Co., Pennsylvania
Hot Air Coal Stoker Stove: Harman Magnum Stoker
Hand Fed Coal Stove: Harman SF-250
Coal Size/Type: Rice or Stove Anthracite Coal
Other Heating: Baseboard Electric

Post by RFK » Fri. Feb. 20, 2015 7:09 pm

Staylo wrote:
Horace wrote:I've run a speed control on my combustion blower for a few years - maybe six, now that I think about it - without incident. The motor is a lot cooler, it's slightly quieter, and I have pretty much infinite control over it. It's the original blower for the stove that was manufactured in 1986, according to the sticker on the stove.
Thanks! That was exactly what I wanted to hear. I assumed that since I am only going to be throttling the blower down a small bit that it would not have been a problem, but it's reassuring to hear from someone who's had one in place that they haven't had any issues.
Staylo, I went back and searched this forum for "Harman Magnum Stoker" and found posts from many other members that have used a speed control on their fan motors with no apparent problems over time. So I wouldn't be concerned. If you are in a hurry to try this, you can probably buy a suitable fan speed control at Lowes. I purchased the Lutron FS-5F, 5 amp controller there recently for about $13.00. I got mine wired up and ready to go, but ran out of the rest of my original 3 tons of coal today so haven't been able to try it yet. It's been too cold to get wet coal at the breaker and I talked with 5 different local coal yards earlier this week. Nobody has any dry rice coal, even those with bagged coal said their bags were as solid as concrete. Two of the dealers didn't even have any rice coal on hand and were having trouble getting their orders filled due freeze up and breakdowns at the breakers. 5-7" more snow coming in tomorrow in my area. Had to change over to kerosene ($$$), and electric heat in the bedrooms for now. It looks like the first full weak of March may be the earliest I can get more coal. Good luck and let us know how you make out.
Rick

 
User avatar
Horace
Member
Posts: 500
Joined: Thu. Sep. 18, 2008 12:15 pm
Location: Central PA
Hot Air Coal Stoker Stove: Harman ST8-VF8 / Frankenstove

Post by Horace » Sun. Feb. 22, 2015 11:21 am

RFK wrote: If you are in a hurry to try this, you can probably buy a suitable fan speed control at Lowes.
That's where I got mine. Wired it into box with an outlet, mounted the box on a board, and plugged it in. Much better heat.

My theory (which is probably crap, but what the hay) is that a motor has only so many revolutions in its lifetime - say 50 bajillion. If I'm running it at half speed then it's going to take me twice as long to get there, therefore the motor should last twice as long ;) . I also thought it seemed sort of foolish to run the blower at full speed and then choke it with a restricter plate. Seems that doing so makes the blower work harder, potentially shortening its life even more.


 
jimbo970
Member
Posts: 184
Joined: Sat. Oct. 14, 2006 9:20 am

Post by jimbo970 » Wed. Jan. 16, 2019 7:28 pm

Horace wrote:
Sun. Feb. 22, 2015 11:21 am
That's where I got mine. Wired it into box with an outlet, mounted the box on a board, and plugged it in. Much better heat.

My theory (which is probably crap, but what the hay) is that a motor has only so many revolutions in its lifetime - say 50 bajillion. If I'm running it at half speed then it's going to take me twice as long to get there, therefore the motor should last twice as long ;) . I also thought it seemed sort of foolish to run the blower at full speed and then choke it with a restricter plate. Seems that doing so makes the blower work harder, potentially shortening its life even more.
horace can you show a pic of your speed control for your combustion motor so I can see how you have it setup and wired

 
dcveem3
Member
Posts: 89
Joined: Sat. Jan. 20, 2018 6:44 pm
Location: NorthWest York Co, PA
Stoker Coal Boiler: Someday!
Hot Air Coal Stoker Stove: Harman Magnum (temp basement duty)
Other Heating: Propane/Heat Pump

Post by dcveem3 » Wed. Jan. 16, 2019 8:36 pm

I don't get the benefit of slowing the fan down. Just close the shutter? The squirrel cage will cavitate and use even less electricity...and you still get the same result. Air control. You are NOT choking a squirrel cage blower when you block-off the air. Matter of fact you can hear the change in rpm...it will go higher since there is no load(air)on the fins of the blower.

Must be an element I'm missing here. Air velocity? Maybe? But not volume.
Don

Post Reply

Return to “Stoker Coal Furnaces & Stoves Using Anthracite (Hot Air)”