DF520 Reducing Unit Questions

I recently decided to start heating with coal, after having used oil for the past 6 years. Today I noticed the stoker was kind of noisy and the motor seemed to be struggling to turn the reducing unit. I checked the oil in the reducing unit and it is extremely thick. The auger is clear and turns freely, and the rest of the linkage to the auger seems to be in alignment. Any ideas as to what the problem could be. For now I'm back on the oil, hopefully I'll get back to coal this weekend. Thanks in advance for any help.

Put a screwdriver handle to your ear and find out exactly where the noise is coming from by touching the end of the screwdriver to each end of the motor, the gearbox and anything it drives. The screwdriver will act as a kind of stethoscope so you can track it down. It could be the motors bearings, the coupling, the gears in the gearbox (noise in the middle), the gearbox bearings (at the shaft ends), or it could be something that just has some loose bolts and is vibrating.

Most low speed gearboxes will use some very thick or heavy oil, it could be as high as 120-140 viscosity. You should check with the manufacturer if the box is not labeled and never overfill it. Some times people will fill them to the top, very bad. There should be a pipe plug in the side for the level, fill from the top until it runs from the side hole, don't overdo it. Let the extra run out, then replug.

Thanks for the reply. I'll look into this tomorrow, or Saturday. It's getting kind of late for me with a 3:15 a.m. get-up.

The oil in your gearbox is a synthetic gear oil, about 90 weight. The gearbox is lubed for life; no maintenance. Turn off the power to the entire unit. Lift up the feed pawl to disengage it from the gear. Can you turn the fan easily with one finger? If not, loosen the set screw on the motor side of the coupler so the coupler is no longer coupled with the motor. If it turns easier, I would suspect the motor. You already said the worm turns easily. Is there oil in the oil pan? Are both ends of the connecting rod oiled, and the bearing assembly shaft? All 3 locations have oil holes.

From sitting for 6 years, your oil points could be dry.

Thanks stoker-man, I followed your instructions and discovered my problem was two-fold. The fan had somehow begun to rub the housing and the coupler to the motor was slightly loose. The fan caused the noise and the loose coupler caused the reducing unit to move more slowly. I took the whole assembly apart, cleaned things out and now it's working as well as it ever did. Thanks again for the replies.

Great! You're going to love the coal savings.