When my father passed away, he left us with a house to sell. Since winter was setting in, the fact that the furnace blower motor would often fail to start when the thermostat called for heat was a big problem. Also, since my sister was living in the house at the time, it was important to have the furnace working properly.
The furnace was an old Lennox gas model (vintage 1955) with an air blower powered by an induction motor with an attached speed control. Because we were not interested in spending thousands of dollars on a new furnace for a house we wanted to sell quickly, we decided to call someone in to repair the blower.
The repairman arrived the next day but was baffled as to why the blower was not working. His recommendation was to get a new furnace. As he was tinkering around with a furnace that was much older than he was, I happened to remember something my father did when this furnace acted up, in the same way, many years ago when I was just a kid. He used to take off the side panel to expose the blower motor and turn the speed control switch to a new position. This procedure allowed the furnace to operate for a while (perhaps a few months) until the process had to be repeated.
I suggested this to the repairman, so he went ahead and turned the speed control knob. This caused the blower to spring into action. The problem was, the next time the blower motor had to start from a standstill, it would not start at all. This meant that a more permanent repair was required. When I asked the repairman if a new switch was available, he said it would be easier to bring about world peace.
So there we were, stuck with a furnace that needed periodic tinkering to keep it going. That is when I decided to take matters into my own hands. Upon taking the speed control switch apart, I noticed that the movable contacts were burned beyond recognition. Since I was willing to accept the loss of having various motor speeds, I decided to solder each movable contact (or what was left of it) to its adjacent stationary contact. This procedure allowed the furnace to work reliably for the two winters that passed by until we finally sold the house.
I have learned at least one thing in life: It sometimes pays to look over someone’s shoulder while he's at work.
This entry was submitted by John Mitchell and edited by Rob Spiegel.
John Rapka is a design engineer at Warren Controls Inc. in Bethlehem, Pa.
Tell us your experience in solving a knotty engineering problem. Send stories to Rob Spiegel for Sherlock Ohms.
The obvious answer (at least obvious to me) to your question is that revealing that the furnace was worked on by someone other than a professional furnace repairman would have thrown up an ugly flag during the inspection process. Possibly, they would have been worried about a fire or an explosion due to what would have been perceived as a novice repair. What this means is that the repair you suggested would have been even worse to reveal (assuming I did the work) because it involved rewiring part of the system. (And NO, I was not about to get another repairman in to work on it after my experience with the last one).
I know that what was done was safe but THEY don't know that because they don't know me. I can feel free to write about this now because I have since learned that the subject furnace has been replaced by a new unit.
John Rapka, I am in almost complete agreement with your fix, but I think your justification about not disclosing it is a stretch. That is, you seem to project that the only forseeable failure scenario, i.e. if new owner wrenched on the control stem, they would make the connection with any subsequent malfunction, effectively lobbing the problem into the new owner's court.
Why not, as another poster has suggested, wire the control completely out of the circuit, and disclose to the buyer that although there originally was a speed control, it wore out and was removed from the system? It's hard to imagine a buyer being deterred by having a one-speed blower.
This tale is another example of how adding a feature removed some quality. My furnace has four speeds available, just by moving one wire to a different terminal, each of which has a quarter-inch "Faston" connector. That arrangement is very reliable and much easier to service.
I don't believe the repair was unethical. The soldered connections that were made were just as reliable as any other permanent electrical connections that existed in the furnace. The chance of them "failing" spontaneously was nil. There would be a problem if someone tried to turn the switch shaft and this resulted in the breakage of the connections made. The chance of this happening was reduced by removing the switch knob. If someone bypassed this preventive measure and broke the connections by turning the switch shaft (with a pair of locking pliers for example), the switch would be reverted to the original open circuit condition assuming the shaft did not get twisted off in the process. If this action caused the blower to no longer work, the person doing the breakage would most likely suspect the switch.
An ingeniuos repair but it bypassed the fullfunctioning of the system and one wonders if the new owners had any idea of what to do if it failed. An open direct wiring repair may have been more transparent.
I agee. I don't think not having variable speed controlsin the furnace is necessary in order to pass an inspection. However, I wouldn't be surprised if there weren't something about the furnace being in "original" operational status in the requirements of the inspection.
Reminds me a lot of automobiles. Just can't fix things like you used to. But stories like this do remind me to at least check for the simple chewing gum and paper clip solutions out there.
The fix of, in essence, hard wireing the speed contorol out of the system is a very valid fix. It is safe, no arcing like the old control that had to be coaxed into action. Would the fix been any better if the control was cut out of the circuit and the wires spliced?
You're right TJ. Even if it's a good fix, it's still not cricket. I remember watching inspectors go though my house and holding my breath as they looked over quick fixes I had made in certain areas and items in the house. Everything worked, but sometimes the solutions were homemade.
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