When the Homeowner Asked "Do You Work on Water Heaters?" We Said Yes.

We take a different approach.

It Started as a Routine AC Maintenance Call

The air conditioning system at this north Boise residence was running well. Clean coil, appropriate charge, no performance concerns. We completed the maintenance and noted a few minor furnace items while we were there, took care of those at no additional charge.

Before we left, the homeowner mentioned two things in passing: the thermostat seemed to behave strangely when the fireplace was on, and the Bosch tankless water heater had been showing an error code.

Neither of those things were on the original work order. Both were worth looking at.

The Thermostat Issue

The homeowner had noticed the air conditioning occasionally running in the middle of winter. Not a system malfunction, a measurement problem.

The thermostat shared a wall riser with the fireplace flue. Warm exhaust air was bleeding through the wire penetration and directly influencing the temperature sensor. The thermostat was reading accurately, it just wasn't reading the right air.

We installed thermal insulation at the penetration to isolate the sensor from the flue, then configured two Ecobee remote sensors in the primary living spaces to give the system a representative averaged reading. Firmware updated, WiFi connectivity restored, system verified stable with the fireplace running.

One degree of variance across all three sensors. The homeowner now has remote access to the system and consistent temperature control throughout the home.

The Water Heater: Repair, Not Replacement

The Bosch tankless unit was displaying error codes, the system's way of flagging that something wasn't right. We scheduled a dedicated visit to evaluate and service the system properly.

On that visit, we completed a full inspection: flow rate, inlet strainer, combustion section, condensate drain, gas pressure at inlet and outlet. Everything within specification. We ran two descale cycles and flushed the system, necessary maintenance that had been deferred.

The error codes cleared. But flow diagnostics told us more: the main water valve servo and bypass valve were still drifting, reading inconsistent flow values even with confirmed nominal flow through the system.

The descale was needed. But it wasn't the cause.

What we found: A cracked and overheated solenoid on the bypass valve assembly.

The failure was causing incorrect feedback to the hot water valve servo, meaning the system couldn't accurately calibrate flow through the heat exchanger. The result was uneven thermal load and persistent error codes that weren't going to resolve on their own.

We ordered the specific bypass valve assembly. When the part arrived, we returned, replaced the valve and gaskets, and calibrated the bypass and main water valve together to 1.6 GPM against a live flow reference. Voltages tested and recorded. Error log cleared and preserved for future reference.

The Bosch unit read 120°F at setpoint. No error codes. Normal operation.

The homeowner kept their water heater.

Why This Visit Matters

A lot of service calls end with a replacement quote. It's a legitimate option, sometimes replacement is the right answer. But replacement before diagnosis means the homeowner never knows if the system could have been saved.

In this case, the system could be saved. It needed specific parts, proper calibration, and a technician willing to work through the diagnostic sequence rather than skip to the end.

That's the standard we hold ourselves to, not because it's faster or simpler, but because it's the right way to service mechanical systems that homeowners depend on.

One item documented for ongoing monitoring: the combustion blower motor exhibited minor noise during operation. Not a performance concern at this time, noted in the service record and flagged for the follow-up visit scheduled for October 2026.