M847D1004 Damper Actuator Motor Replacement for Honeywell Zone M847DM847D1004 Damper Motor, Old ARD and ZD Series HVAC Zone General Purpose Spring Return 2-Wire Damper Actuator, 24 VAC

My old one had started to strip teeth (see pics) and would bind. Altogether creating bad zoning. Easy replacement - I had messed up at first and installed with the damper close when the zone was on.. easy fix once I realized it wasn't zoning correctly.Hopefully this has good longevity. I will update this review if I have any issues but so far so good.

The item was not exact as stated on the description.

The description states this part fits a 5/16” diameter damper shaft. However, the brass sleeve diameter was about 1/32” too small based on measurement and the fact that it would not slide onto the 5/16” shaft. I had to put it on the drill press to bore out the sleeve to 5/16”. The description also provides a “tip” to reuse the original (longer) set screw. However, the threads on this damper actuator were slightly too small for the original set screw so I had to gently cut new threads for the original set screw to fit. After modifying this exact fit replacement for M847D1004, it seems to work well.

I have a 15+ year old Honeywell zone system splitting my house into two zones. I have nursed my original Honeywell damper actuators along over the years with various repairs, so it's nice to finally have a brand new replacement unit. My initial impression is that It seems at least as well made as the originals, and functions well. Time will tell, but I am optimistic.

This damper actuator motor was easy to install and works perfectly in my HVAC system. It’s a solid replacement part.

The sleeve is too small for the shaft. But I Made it work.