A condenser fan motor burns out. You replace it. Eight months later, the ECM blower module on the same building fails. Then a contactor welds, a capacitor swells, a control board cooks. Each part gets warrantied or swapped, the customer gets more frustrated, and nobody can say why this building eats equipment.
If that pattern sounds familiar — especially across Tyler, Longview, and the rest of East Texas — there’s a cause that rarely makes it onto the service ticket: the voltage feeding the equipment is too high, all day, every day.
The symptom looks like bad equipment. It usually isn’t.
Repeat HVAC failures get blamed on the obvious suspects first — a bad batch of motors, a rushed install, a dirty coil running everything hot. Sometimes that’s it. But when different components keep dying on the same service, and the replacements don’t last either, the common denominator isn’t the parts. It’s the power.
Modern HVAC equipment is far more voltage-sensitive than the gear it replaced. ECM and inverter-driven motors, variable-speed boards, and the switching power supplies inside them are electronic devices. Feed them sustained overvoltage and they run hotter than designed, capacitors age faster, and semiconductors fail early. A unit rated for a long service life can lose years to a problem that never trips a breaker and never shows up on a quick meter check.
The hidden cause: sustained grid overvoltage
Utilities don’t deliver one exact voltage. They’re allowed to deliver service across a band, and in practice many feeders run toward the top of that band — it gives them headroom against voltage drop at the far end of the line. In areas on the Oncor grid around East Texas, a nominal 240V service is commonly measured sitting near, or above, the high end of the allowable range for hours at a stretch, particularly during lighter-load periods like overnight and shoulder seasons.
A few volts over nominal doesn’t sound like much. But “a few volts over, continuously, for years” is a different stress than the occasional surge equipment is built to shrug off. It’s the sustained part that quietly shortens the life of everything downstream.
Two things make East Texas a hot spot for this:
1. Feeders that run high. Long rural and suburban runs are often set up on the high side to compensate for drop, so the near-end equipment sees more than nameplate. 2. Newer high-efficiency equipment. The ECM/inverter gear that’s replaced old PSC motors is more efficient — and more sensitive to the voltage it’s fed.
Detect before you spend another dime on parts
Before you change one more motor, confirm what the equipment is actually being fed.
- Measure under load, over time — not with one spot check. A multimeter reading at 9 a.m. tells you almost nothing. Voltage moves with grid load through the day. Put a data logger on the supply and watch it across a full duty cycle, ideally a few days, so you catch the overnight and light-load peaks.
- Compare to the nameplate and the allowable range. Line the logged voltage up against the equipment’s rated input and the service voltage range. If it’s parked at or above the top of the range for long stretches, you’ve found your problem.
- Look at the failure history. Multiple different components failing early on one service is the tell. It points at the power, not the parts.
This is the detect half of the job, and it’s the half that gets skipped. Skipping it is why the same building keeps coming back.
Eliminate it — permanently — with a buck-boost transformer
Once you’ve confirmed a consistent over-voltage (or under-voltage) condition, you don’t manage it. You eliminate it.
A buck-boost transformer is the standard, code-recognized fix for a fixed voltage offset. Wired to buck, it steps an over-voltage feed down to spec — for example, knocking a feed that sits around 250V back to roughly 236V. Wired to boost, it brings a low feed up. Either way, the equipment finally sees the voltage it was engineered for, every hour of every day. It’s a one-time correction, not another part on the truck.
For HVAC, the correction is almost always small and well-defined — exactly what buck-boost transformers are designed to do. You size the unit by the load amps and the size of the correction, and because these are standard ratings, the right transformer is something you can buy from stock and install this week instead of quoting and waiting weeks.
Wiring it up
Buck-boost connections are straightforward for a qualified electrician, but they have to be right — the same transformer wires differently for buck versus boost, and for the specific voltages you’re correcting. For step-by-step wiring diagrams and installation how-to, hand the install off to our companion site: transformerinstall.com.
The takeaway
When one building in East Texas keeps killing HVAC equipment, stop replacing parts and start measuring power. Detect the overvoltage with a logger; eliminate it with a correctly sized buck-boost transformer. Do that once, and the callbacks stop.