Everyone makes mistakes.
The important thing is not to make the same mistake twice.
Each quarter we will take a moment to review a few details where encountered a learning experience of some sort. The goal is not to point fingers or assign blame, but rather to create a space to learn from our collaborative experience, and offer resources so that if these issues ever occur in the future, you know what you are looking for, and how to *hopefully* ward of costly errors.
Hulk-Smash.... the FPB.
The Issue:
Our crews were installing a fan-powered box on site and were in the process of elevating it for installation on the duct jack. When it reached about 10' off the ground, the jack suddenly DROPPED about 18”, which caused the FPB to fall off and SMASH to the floor!
Thankfully, nobody was injured.
​
The reason this happened is because at some point before the duct jack was overloaded. When that happens it puts added stress on the mast pinching the cable. This causes slack to build up. When it can’t handle stress, it lets go and jack drops until the slack is gone.
The Fix:
Don’t ever overload jacks-- just because it might work once, doesn't mean it will always be that way. Know what you are lifting and your capacity.
Also, don’t allow anyone else to use our jacks. Other trades are notorious for overloading them. Each duct jack costs about $4000 so it can add up fast (think like an owner), not to mention the potential injuries and damaged equipment.
LEARN:
Check out our MCI STAT Course on Duct Jacks, and freshen up your knowledge on capacities! See mm. 9:01.
Wild Wiring
The Issue:
Our electrical subcontractor ran thermostat wire for a 480v unit; the transformer was a multi-tap with a 480v option. Turns out, they ran it as 277, tapping off of the 24v coil side of the contactor for the ‘neutral.’ There is not a neutral wired to this unit (note that there is no white wire on the right), so it was wired to ground.
The wire hit a sharp metal edge in this unit and shorted out.
Takeaways:
-
Just because they're supposed to be the experts hired to do the job, doesn't necessarily mean they know what they're doing. Check behind your subs, and read the wiring diagram to make sure their work is correct.
-
Check out this information from our friends at HVAC Know It All on reading HVAC wiring diagrams.
When you make a mistake there are only three things you should ever do about it: admit it, learn from it, and don't repeat it.
Paul Bear Bryant
Have you come across a learning experience?
Let us know. We may have educational resources that we can share to the benefit of all.