Climatic Chamber Test: Verification of the Resistance of One Pump Circulators to Extreme and Condensing Temperatures

In the context of energy efficiency and sustainability, the reliability of components used in HVAC (Heating, Ventilation, and Air Conditioning) systems is crucial. Among these, circulators play a key role in ensuring the proper movement of thermal fluids, especially under challenging operating conditions.

To validate their performance, beyond the mandatory product certifications issued by external bodies that confirm the declared class, circulators must also undergo rigorous in-house testing that simulates extreme environments. This is precisely the approach we take with all our products—multiple times per year—inside our climatic chamber, where One Pump circulators are subjected to intense condensing temperatures that far exceed any real-world conditions they might encounter during use.

This article details:

• The test objectives and context

• The configuration of the climatic chamber

• The measurement methods and monitored parameters

• The results obtained

• Technical and application-related insights

1. Test Objectives

The main goal of the test was to evaluate the mechanical, electronic, and functional resistance of One Pump circulators under conditions including:

• High levels of relative humidity

• Temperatures near the dew point

• Repeated thermal cycles with significant surface and internal condensation within the motor

Why test under condensing conditions?

In real-world applications (boiler rooms, radiant systems, geothermal systems, etc.), circulators can be exposed to environmental conditions where humidity condenses on the device’s cold surfaces. This can cause:

• Infiltration into electronic components

• Corrosion of metal parts

• Premature failure

• Malfunctions due to changes in electrical resistance

2. The Climatic Chamber: Structure and Settings

Environment Setup

The climatic chamber was configured to reproduce controlled ambient conditions with the following parameters:

• Internal temperature: from -5 °C to +60 °C, with programmable gradients

• Relative humidity: up to 98%

• Forced ventilation to simulate air flows and enhance condensation

• Test duration: continuous cycles exceeding 100 hours

Monitoring Equipment

As shown in the images, the control panel includes:

• Digital thermostats for managing supply/return temperatures

• Humidity sensors

• Remote monitoring via data logger

• Touch display system for real-time analysis

The panel is divided into control zones for two separate pumps (Pump 1 and Pump 2), each equipped with sensors for flow, return, pressure, and volume.

3. Description of the One Pump Circulators

The tested One Pump circulators are compact, efficient devices designed for residential and commercial environments. Key features include:

• High-efficiency brushless motor

• Die-cast aluminum body with corrosion-resistant treatment

• Integrated electronic control with over-temperature and over-voltage protection

• Standardized mechanical and hydraulic connections

The tests focused on models designed for installation in high-humidity environments.

4. Test Phases: Detailed Methodology

1. Preliminary Checks and Setup

• Visual inspection of circulators: absence of mechanical damage, corrosion, or defects

• Documentation verification: model, serial number, nameplate data (EN 60335 §7)

• Mounting on the test bench: installation on a dedicated support with closed hydraulic loop and compatible test fluid

• Electrical connections: connection to power supplies with protection systems and monitoring instrumentation

2. Dry Run Test (Pre-conditioning)(EN 60335 §11 - heating; §19 - abnormal operation)

• Operation in controlled environment (20–25 °C, RH ≈ 50%) for at least 24 hours

• Monitoring of:

  • Motor temperature

  • Electrical current draw

  • Anomalies (noise, vibrations, thermal protections)

3. Initial Condition Check

• Leak testing of hydraulic system

• Calibration and functionality check of measuring instruments (T°, P, V, I)

• Reset of data acquisition systems

4. Insertion into Climatic Chamber

• Placement of the test bench (or pump body) inside the climatic chamber

• Remote connection to sensors and power

• Thermal insulation of external connections

5. Start of Condensing Environmental Cycle(IEC 60068-2-30: Test Db – 12+12 h cycles with RH > 93%)

• Minimum: 4 full 24-hour cycles; Maximum: 6 cycles (144 h)

• Climate Phases:

  • 12 h at 25 °C, RH > 95% → condensation formation

  • Transition to 55 °C, RH > 93% in < 3 hours → maintained for 12 h

• During testing:

  • Internal fluid cooled to 5 °C → thermal gradient generation

  • Humidity kept >98% → highly condensing environment

6. Simulation of ON-OFF Operating Cycles

• Programmed functional cycles: 30 min ON / 30 min OFF

• Performance monitoring under condensation

• Measurement of current draw, stability, and activation of protections

7. Additional Thermal Stress

• Chamber temperature increased to 45 °C with high RH maintained

• Optional fast temperature changes (thermal shock)

8. Continuous Monitoring

• Continuous logging of:

  • Temperature (motor, ambient, fluid)

  • Relative humidity

  • Absorbed current

  • Pressure and flow (if required)

• Automatic detection/log of malfunctions

9. End of Test and Return to Normal Conditions

• Gradual return to 20–25 °C and RH < 60%

• Shutdown and removal of circulators from chamber

10. Final Functional and Visual Inspection

• Visual check for:

  • Residual condensation

  • Oxidation/corrosion

  • Infiltrations or cracks

• Cold functionality test:

  • Start-up, current draw, stability, performance drop

• Internal inspection (if planned):

  • Seals, insulation, wiring, PCBs

11. Additional Tests (EN 60335)

• §16 – Leakage current and dielectric strength:

  • Insulation > 1 MΩ

  • Test voltage ≈ 500 V AC

• §29 – Humidity resistance:

  • Check insulated/protected areas

  • Penetration test (optional IP rating)

• §30 – Mechanical safety:

  • Structural deformation or impact hazard assessment

12. Final Technical Report

• Compilation of all recorded data (charts, tables, photos)

• Comparison of initial and final conditions

• Evaluation vs. requirements:

  • Design specs

  • EN/IEC standards

  • Internal protocol

• Final outcome: compliant / non-compliant + recommendations

5. Observed Results

Thermal Behavior

One Pump circulators maintained stable internal temperatures even during peak humidity, with no signs of internal condensation. Heat dissipation remained within design limits.

Surface Condensation: Effectively Managed

External surfaces showed expected condensation (visible in image 2), but no internal infiltration occurred. Seals held effectively. Electrical cables showed no moisture ingress.

Corrosion and Mechanical Resistance

Screws and metal surfaces showed no significant corrosion thanks to protective treatments. No deformation was observed in flanges or pump bodies.

Electrical Operation

Control circuits showed no interruptions, contact issues, or malfunctions—even with visible surface condensation. Circuit inspection post-test confirmed no signs of oxidation or damage.

6. Real-World Environmental Simulation

Simulated Scenario: Boiler Room or Technical Area

One image shows a key scenario: water vapor release inside a space, mimicking poorly ventilated boiler rooms. The test confirmed One Pump circulators can operate without additional protection in such environments.

Application Relevance

This ensures higher reliability in:

• Installations in damp areas (basements, technical rooms)

• Heating systems in unconditioned buildings

• Industrial environments with vapor presence

7. Conclusions and Outlook

The climatic chamber tests yielded highly encouraging results, showing that One Pump circulators:

• Remain reliable even under condensation

• Do not show structural degradation

• Operate correctly for extended periods in critical conditions(>100 hours of continuous testing per model – with 3 units tested per model)

Benefits for Designers and End Users

• Longer product lifespan

• Reduced need for preventive maintenance

• Suitable for “difficult” installations

• Easy to install – no additional protection shells required

8. Future Developments

Based on these tests, the next steps include:

• Accelerated aging analysis (over 10,000 hours)

• Salt spray testing for marine corrosion resistance

• Combined tests with mechanical stress (vibration, impact)

• Development of next-gen models with even more advanced protection

Appendix: Photo Gallery

• Test control station – labeled inlets, outlets, and pressures

• Visual and technical inspection: confirmed structural and functional integrity

📌 Post-Test Observations

• No corrosion on critical components (e.g. screw zones often prone to pitting in humid environments)

• Effective drainage: no water accumulation, confirmed by endoscopic checks and insulation resistance measurements

• Electrical safety maintained:

  • Insulation >1 MΩ post-test

  • Dielectric strength passed: 500 V AC, no discharge or tracking

  • No PCB or wiring damage

• Unchanged functionality:

  • Stable current draw

  • Regular startup

  • No abnormal noise or vibration

9. Testing Beyond Certification Standards

Testing Under Stricter-Than-Norm Conditions

Unlike CE or ErP certification tests, which replicate “reasonable” environments, this test reproduces far harsher scenarios, such as poorly ventilated humid technical rooms.

Our internal climatic test involved:

• RH above 95%

• Repeated condensation cycles

• No added ventilation

• Over 100 hours of exposure

This goes beyond merely “passing a test”—it guarantees operational robustness so that anyone installing a One Pump circulator never has to worry about ambient conditions.

Where certification standards end, One Pump’s internal tests begin.

10. One Pump’s Commitment to Reliability

These tests reflect an approach that goes far beyond what’s required. In a market where passing homologation is often seen as the finish line, One Pump voluntarily subjects its products to extreme tests to ensure customers never face failures caused by predictable environmental conditions.

Real-World Quality Commitment

These internal tests:

• Are not mandatory

• Are not requested by any regulatory body

• Require significant cost and engineering resources

Yet they are performed regularly as part of our product validation and continuous improvement process.

A Technical and Cultural Responsibility

In an industry often driven by cost and speed, we consciously choose the most demanding path: proven quality.

Our tests are not mere lab routines—they’re an act of technical responsibility toward our customers.

When you choose One Pump, you choose a circulator that has already passed the toughest challenges. Because in the field, performance that lasts makes all the difference.

Acknowledgment

We would like to express our sincere thanks to Zymbo Italia for their valuable technical support and collaboration in conducting these tests.

The use of their advanced climatic chamber was instrumental in reproducing extreme environmental conditions with precision and reliability. The expertise of the Zymbo team and the quality of their testing infrastructure significantly contributed to the accuracy and success of the project.