We finally have heat again after more than 2 weeks. I’ve been using 3 portable electric space heaters and a gas fireplace in the basement in the mean time.
My ordeal started when the furnace started making occasional screeching sounds back in August. Kind of like scraping nails on a chalk board. It got worse until it became continuous and the furnace started vibrating violently. At that point I shut it off and took the blower assembly out.
It turns out that Goodman, the furnace manufacturer, makes the blower wheels with vanes of metal that are slipped over a central disc that mounts to the motor shaft. That disc, amazingly, is not welded, screwed, clipped, or soldered to the vanes. The disk has a V-groove along it’s outer edge, kind of like a pulley and the vanes have a corresponding V shaped protrusion that drops in that groove and that’s it - it’s just friction-fit. No means of securing one to the other.
So, over time, the vanes start to slip. That’s the intermittent screeching. But, of course, as they do so, the edge of the disc starts to cut into the vanes gradually making the V-protrusions smaller and less tightly fitting. So the screeching becomes more frequent and louder until it lets go completely until you have the disc rotating at one speed and the vanes, because of air resistance, rotating more slowly. It eventually becomes unbalanced, starts to vibrate and that’s that.
Simple. Go to Goodman’s distribution outlet in Brantford and get a new one.
I brought the model number of the furnace, the model number printed on the blower wheel (which was damaged and possibly incomplete) and the blower wheel itself with me just to be sure I was getting an exact replacement.
They flat out refused to sell it to me.
They said I had to have a gas-fitters technician license to buy a fan.
They then gave me a list of local HVAC service companies I could call to get the blower wheel replaced.
Man was I pissed. I’m not paying someone $200/hr to come to my house, verify the blower wheel I’ve already taken out, drive to Goodman’s distribution center I was already at, drive back to my house, and install it when I can clearly do it myself. I have called and HVAC tech in the past whenever there’s an issue with the gas side of the furnace, but the electrical and mechanical side - that’s my domain.
That’s also how I know that they charge $200/hr and that they won’t take your educated word for what’s wrong with the furnace; they’ll only act on what they’ve come out to see with their own eyes, charging you a service call for the privilege of doing so. To some degree, I get that, but it would be nice to not be treated as incompetent after you’ve assured them that you are, yourself, a (retired) technician, albeit in a related, but different field.
So out of spite, I ordered the part from the States and had to wait 6 days (including a weekend) for it to clear customs and arrive.
The part that arrived was the right one but the vane assembly had a slight tilt to it - think trapezoid vs rectangle. I mounted it on the motor and gave it a spin and it clearly was not centered. I shot a 10s video of it with me manually giving it a spin. Still, the vanes had 5 balancing weights attached to them, so someone must have balanced it at the factory and they obviously hadn’t rejected it, and while it just felt wrong, I installed it anyway.
It ran, noisily, but at one point during the night it got really loud and started shaking the floor boards (bedroom is over the furnace), so I shut it off for the night and looked at it in the morning.
I filmed the furnace vibrating and took the assembly out again and sent both videos to the retailer who immediately replaced it. The replacement arrived today and runs smooth as silk.
So by now you’re probably wondering why I’m posting this, aside from getting 2+weeks of frustration off my chest.
When the replacement wheel started vibrating violently, and before I could get downstairs to turn it off, it did some damage to the furnace. Specifically, it cause the screw holding the top of an inductor to come out. I found it on the floor of the furnace. With top screw gone, the inductor started vibrating backwards until the metal fatigue snapped the lower mount.
I didn’t want to mount it with only one screw, so I had the idea of modelling a plastic housing for the inductor core. I had to print it twice because the first one was a little bit too tight and forcing on caused it to split along the layer lines. I had to re-design it for a slightly larger core. The alternative was to try to find a source for a replacement inductor and then waiting another week.
3D Printing to the rescue. It’s nice to finally have proper heating again.