Key Takeaways
- Resistance testing before installation establishes a baseline. Measuring ohms across each element before power-up catches open elements that would otherwise trigger callbacks within weeks.
- Know your parallel configurations. A 10kW kit is usually two 5kW elements in parallel. Each element reads 10-12 ohms individually; the total kit reads ~5.8 ohms at the main lugs. If the total reads ~11.5 ohms, one element is open.
- Sequencers hide element failures. A single open element in a multi-stage heat kit may not trigger obvious symptoms until the coldest night of the year, when the customer calls at 2 AM.
- Pre-install testing takes 5 minutes. Post-callback diagnosis, truck roll, and customer frustration take considerably longer.
Heating season means heat kit installs. A quick resistance test before power-up verifies what’s actually in the box. Takes five minutes. Most techs don’t bother.
