Quality and Compliance: Evidence, Testing, and Change Control

Evidence, not badges

A thermostat is a low-cost device that can shut down a building, trip a breaker, or misreport a temperature for a year before anyone notices. Quality in this product class is mostly about what you can prove after something goes wrong. This page describes the evidence we keep and the limits of what we claim.

Incoming and supplier control

Components arrive against an approved specification, with lot-level inspection on the parts that affect safety or calibration. Critical semiconductors, relays, and temperature sensors are bought from authorized channels; brokers are not used for these categories, because a remarked relay is indistinguishable from a genuine one until it welds shut.

Suppliers are qualified on their process and their change notification behavior, not only on price. A supplier that substitutes a dielectric or a plating without telling anyone creates a field failure that appears two seasons later.

Build and test

SMT lines run with solder paste inspection and automated optical inspection. Boards are programmed and calibrated on fixtures designed with the product, and every unit goes through a functional test that exercises the outputs, the sensor inputs, the display, and the communication interface where fitted.

Functional test limits come from the design verification, not from what the fixture happens to be able to measure. Test records are stored against the serial number, together with the firmware version and the fixture identifier, so a field return can be traced back to the exact build condition.

Traceability

Each unit carries a serial or lot identifier that maps to the production date, the component lots for safety-critical parts, the firmware release, and the test result. For line-voltage products, the identifier also maps to the isolation test record. This is what turns a containment decision into a data exercise rather than a guess.

Reliability work

Design verification includes thermal cycling, elevated-temperature operating life on a sample basis, and repeated relay or triac switching at rated and inductive loads. Line-voltage designs get hipot and insulation resistance testing on every unit, not only on a sample.

Where a customer has a field failure rate target, we agree how it is measured and what data the customer will share. A warranty discussion without failure data is a negotiation; with data it is an engineering problem.

Compliance routes

We do not publish certificate numbers or claim marks on this page. For a new private-label product, the applicable requirements depend on the destination market, the device class, the load, and whether a radio is present. Typical routes involve the IEC 60730 or UL 60730 family for automatic electrical controls, FCC Part 15 and ISED rules for intentional radiators in the United States and Canada, and the EMC, Low Voltage, and Radio Equipment Directives for the European Union, together with RoHS and REACH obligations.

The program agreement names the certificate holder and the importer of record. Test reports are issued to that holder. We prepare the technical construction file, coordinate with the nominated laboratory, and supply the samples and documentation the testing requires. If a customer already holds a certification for a related model, we assess whether the change is a variant or a new filing before anyone assumes it is a paperwork exercise.

Documentation package

Depending on the contract, the package can include schematics, PCB layout, bill of materials, approved vendor list, assembly drawings, test specifications and limits, calibration procedure, firmware release notes, and the user and installation manuals. A customer who intends to dual-source the product later should say so at the start, because that changes what has to be documented.

Change control and problems

Any change to a component, a supplier, a process, or firmware triggers a customer notification with an assessment of form, fit, function, and regulatory impact. Production does not switch revisions without written approval.

For a field problem, we support a structured root-cause process with containment, escape point analysis, and corrective action, and we share the test and build records the analysis needs. We would rather find the cause with the customer than replace units until the complaints stop.

What we do not claim

We do not assert that a product is certified before a certificate exists, and we do not describe a quality system as certified unless the certificate is current and covers the site that makes the product. Buyers doing supplier qualification should ask for the documents and audit the site; a web page is not evidence.

The OEM process shows where compliance sits in a program; contact is the place to request the documentation list.