Harman Mark III blower

I have had the Harman Mark III fired up with coal now for the last two weeks. Finally learned how to burn the coal and am loving it. Another question for the Masters of the art. How long is it safe or okay to leave the blower on the furnace on. This thing has been blowing hot air for the last two weeks. Will the stove get too hot if I unplug the fan for a couple of hours or so. I didn't know if the fans were designed to be on until spring (LOL). I can idle the stove down somewhat but still learning this part. Thanks for the help.

From what I've seen and heard here the fans are up to the task of 24/7 operation . I would prolly put a rheostat on it though, running full blast all the time would make me crazy not to mention on warmer days like today might be too much heat in the air a little more radiant would be better

I didn't do well in science class so, what is a Rheostat and where can I get one and how does it hook up?

Thanks,

Bryan

A Rheostat is a variable resistor to slow motors down, However, the Motor/Fan must be a shaded pole type motors, a capacitor start type motor will not work. Do a search on here and there has been many discussions on rheostats and how to hook them up and use them.

Basically "like" a dimmer switch for a light (But don't use one, it could burn up the motor), those are only designed for for incandescent light bulbs.

Here;s a few choices

http://electricmotorwarehouse.com/kbwc.htm

http://www.aero-flo.com/catalog/

My blower has been on months at a time with no problems, it is still running after 14 years. I vacuum off the screen occasionally and once a year oil it a little and clean it more thoroughly.

I run mine nearly 24/7. Unfortunately, due to where my stove is located, the oiling holes are pointed down so lubing it is difficult. I'm on my second fan in six years. They don't die, but the bearings wear out and they start knocking. It's fairly annoying.

I run the blower on my MK II just about all the time. On days like today, (it's 58) I just turn it off. I have had my stove for 14 years and I put a new blower on it this year. The old one still runs but, the wires are burned and the bearings are just about shot. It's a Fasco B75. BTW, the old blower was used when I purchased the stove so I really have no complaints. I purchased it from an electric motor supply house for 70% less than a stove dealer wanted.

titleist1 wrote:My blower has been on months at a time with no problems, it is still running after 14 years. I vacuum off the screen occasionally and once a year oil it a little and clean it more thoroughly.

When I first installed my Mark I the blower was run as I got it, but after a few weeks I had to spend some time cleaning the dog and cat fur out of the squirrel cage with a brush and compressed air. I removed the 2 screws holding the wire guard on the intake and fitted a piece of A/C filter over the wire mesh, under the bracket. No problems since, I just vacuum it off when it's dirty.

I also fitted a switch to the connection box, so I don't have to keep unplugging it. I later rewired the wall receptacle to switch one outlet off when I shut the switch off for my through the wall heating scavenger.

The motor doesn't have bearings, just bushings. This is common in small motors that don't run under heavy loads.

jpete wrote:I run mine nearly 24/7. Unfortunately, due to where my stove is located, the oiling holes are pointed down so lubing it is difficult. I'm on my second fan in six years. They don't die, but the bearings wear out and they start knocking. It's fairly annoying.

Can't you remove the assembly from the back of the stove to lube it?

WoodnCoal...Do you put a couple drops of oil in your occasionally or are you saying it doesn't need it per your bushings vs. bearings comment? I didn't bother to dig out the drawing for it, but I thought I remembered it mentioning the oil "wells" that would drip down to the shaft. I could definitely be confusing it with another piece of equipment floating around the homestead, though. I do have to take mine off to oil it, but only do that once a year when I give it a good cleaning. It's pretty easy to slide it up out of the bracket.

The new stove came with a fan, but I left it in the box and installed the one that was on the old stove since it was still running.

The motor still needs to be oiled occasionally. I haven't oiled mine yet, its due I'm sure. Bearing motors need more frequent oiling, more moving parts. The fan motor has just the armature shaft ends spinning in machined bushings that are held in sockets at each end of the housing. There is usually some type of absorbent material around them that holds the oil. These motors run under a light load, so the bushings aren't stressed as much as larger motors handling heavier loads. I also blow all the dust and fur out of the cooling slots on the motor with compressed air. Basically the same thing I do to the Bathroom exhaust fan about once a year.