Accurate Thermal Systems calibration ensures your dry-block temperature sources remain stable, traceable, and compliant with ISO 17025 requirements. Whether you use ThermCal 400 or another ATS model, calibration is essential to maintain accuracy, support audit readiness, and protect product quality across regulated environments.
Dry-well calibrators do not “measure” temperature — they generate a controlled reference. Because they act as the upstream temperature source for other instruments, a small drift inside the dry-well can cascade into every downstream device you verify. That is why auditors scrutinize their calibration history more than thermometer records.
A properly calibrated ATS unit protects three things:
-
Measurement integrity
-
Compliance traceability
-
Production reliability
What is Accurate Thermal Systems?
Accurate Thermal Systems (ATS) designs precision dry-block and dry-well calibrators used as temperature sources for probe, RTD, and thermometer verification. These instruments create a highly controlled thermal environment, allowing sensors to be compared against a reference standard.
Dry block / dry-well calibrators vs. temperature sources
| Term | Meaning | Why it matters |
|---|---|---|
| Dry-block / dry-well | Physical block heated to a target setpoint | Provides the “environment” |
| Temperature source | Functional role of the instrument | Supplies reference temperature |
Your ATS unit is both:
A dry-block form factor + a temperature source function.
Why these devices require periodic calibration
Because the dry-block itself becomes the “standard” for downstream measurements, any drift affects every sensor you validate. Drift may come from:
-
aging heaters
-
changes in thermal stability
-
controller deviation
-
insulation wear over time
Where they are used
Dry-well calibrators like the ThermCal series are widely used in:
-
pharmaceutical and biotech facilities
-
cleanrooms and environmental monitoring
-
manufacturing QA/QC labs
-
R&D and process calibration benches
Why Calibration is Non-Negotiable
A dry-well is an upstream reference. When it drifts, every thermometer downstream becomes invalid.
Traceability
If the source drifts, the entire measurement chain loses integrity.
Compliance
ISO 17025 and GMP treat dry-wells as critical reference devices.
Audit Readiness
Auditors inspect the source first. If it fails, everything downstream fails.
Risk Prevention
Prevents hidden drift from turning into product risk or CAPA findings.
Devices Covered
This service applies to all major Accurate Thermal Systems dry-well calibrators, including the ThermCal 400, ThermCal 130, and the D-Series models. Although their size and range differ, the calibration principles remain the same: the device must generate a stable and traceable temperature source across its operating span.
Many ATS units use interchangeable inserts; therefore, inserts should also be verified when different probe diameters or tolerances are used. A poor fit can introduce conduction error or affect uniformity inside the well.
Calibration Methods (How It’s Performed)
Dry-well calibrators are validated by comparing their output temperature against a higher-accuracy reference standard. The goal is not only to check the setpoint, but also the true block temperature delivered to the probe.
Reference standard
A dry-well must be compared against a certified reference thermometer or SPRT.
This external reference has a lower uncertainty than the unit under test, which protects traceability.
Without a higher-class reference, the comparison is technically invalid.
Stability check
Before readings are taken, the dry-block must reach thermal stability.
This ensures the well is no longer drifting.
Stability is confirmed when the reference probe shows minimal fluctuation over time.
Even a shallow drift can indicate controller deviation or heater aging.
Measurement points
The device is verified at multiple test points across its usable range.
Typical points include:
-
low range
-
mid range
-
high range
This ensures the calibrator is accurate throughout its operating envelope, not only at a single setpoint.
Dwell time / thermal equilibrium
After reaching a test point, technicians allow the device to “soak” until both the block and the reference are in equilibrium.
If dwell time is too short, the reading may reflect surface temperature rather than block temperature.
Therefore, equilibrium is key to valid results.
Uncertainty contributors
Several factors influence overall uncertainty, including:
-
reference thermometer accuracy
-
block uniformity
-
axial gradient
-
immersion depth
-
insert fit / probe contact
These contributors become part of the final uncertainty budget shown on an ISO 17025 certificate.
Our ISO 17025 Calibration Process
An ISO 17025 calibration is more than a functional check.
It must prove traceability, demonstrate method validity, and document measurement integrity in a way that stands up to auditor review.
As-found / As-left data
The process begins with an as-found test to document the device condition before any adjustment.
This shows whether the unit was still within tolerance.
After verification or correction, an as-left test confirms final performance.
Auditors look for both.
NIST traceability
All readings use a NIST-traceable reference thermometer. This traceability chain supports your records during inspections and customer audits. Without it, the certificate does not meet compliance requirements.
Adjustment (if applicable)
Some ATS models allow internal adjustments when drift is detected.
If an adjustment is made, it is documented with revision notes to show transparency in the correction.
This protects auditors from assuming the device “passed by default.”
Environmental validation
Dry-well measurements can be influenced by ambient temperature and stability.
Therefore, laboratory conditions are also recorded on the certificate.
Certificate structure
A defensible ISO 17025 certificate typically includes:
-
as-found / as-left results
-
reference standard ID
-
uncertainty values
-
measurement points
-
environmental conditions
-
calibration method
-
technician and accreditation details
This structure is what differentiates a real calibration from a basic performance check.
Service Options
Onsite Calibration (recommended for GMP & cleanrooms)
-
No shipping or handling risk
-
Minimal downtime
-
Calibrated in the actual operating environment
Mail-in / Depot Calibration
-
Cost-effective for non-critical units
-
Scheduled return windows
-
Suitable when downtime is acceptable
Turnaround & Scheduling
-
Standard or expedited options
-
Pre-booking helps production continuity
-
Certificates delivered immediately after completion
Preventive Maintenance Included
-
Visual condition check
-
Insert fit / contact review
-
Controller stability assessment
What You Receive
After calibration, you receive a full ISO 17025 certificate with as-found and as-left data, the reference standard used, and the final measurement uncertainty. The documents are NIST-traceable and formatted for easy audit review, so you do not need extra clarification later on. In addition, your unit returns with an updated asset label and a clear due date, which keeps maintenance records clean and inspection-ready. As a result, the device can go back into service immediately.
Recommended Calibration Frequency (Risk-Based)
Pick an interval by risk tier. Tighten after any failure, repair, or audit finding.
Auditor tip: Document your rationale for the chosen tier. Update the interval after any OOS, failure, or process change.
Industries Served
- Life Sciences & Biotech – cleanrooms and EM checks rely on a stable temperature source
- Pharma & Medical Devices – GMP audits require clear traceability records
- Food & Beverage – process lines need consistent temperature control
- Aerospace & Defense – teams need repeatable and reliable methods
- Semiconductor & Electronics – high uptime makes onsite service more practical
- Manufacturing QA/QC – planned intervals help avoid downtime
- Utilities & Facilities – environmental monitoring depends on upstream accuracy
- Calibration Labs & R&D – full before/after data supports validation work
If your ATS dry-well is coming due for calibration, we can help you stay compliant and avoid downtime. Both onsite and mail-in service are available, and certificates are delivered as soon as the work is complete.
