Testo External Vacuum Probe for Testo 557 Digital Manifold | 0638 1557

Testo External Vacuum Probe for Testo 557 Digital Manifold — 0638 1557

The Testo 0638 1557 is an external vacuum probe designed for use with the Testo 557 digital manifold, providing faster and more reliable evacuation measurements than the manifold's built-in vacuum sensor. By placing the probe closer to the system being evacuated — rather than measuring at the manifold — you get a more accurate representation of the actual vacuum level in the system, reducing the risk of releasing a system before a true deep vacuum has been achieved.

With a measuring range of 0 to 20,000 microns and a resolution of 1 micron in the 0–1,000 micron range, the 0638 1557 is suited to HVAC/R technicians who need precise vacuum measurement during system evacuation on residential and commercial AC and refrigeration systems.

This probe is designed specifically for the Testo 557 digital manifold. Confirm compatibility with your specific Testo manifold model before ordering. Confirm all specifications against the Testo manufacturer’s current datasheet.

Key Features

• Designed for use with the Testo 557 digital manifold
• Measuring range: 0 to 20,000 microns
• Resolution: 1 micron (0–1,000 micron range)
• Provides faster, more reliable evacuation readings than manifold-mounted sensors
• Positions closer to the system for more accurate vacuum level measurement
• SKU / Order code: 0638 1557

Specifications

• Measuring range: 0 to 20,000 micron
• Accuracy: ±(10 micron + 10% of measured value) — 100 to 1,000 micron range
• Resolution: 1 micron (0–1,000) | 10 micron (1,000–2,000) | 100 micron (2,000–5,000) | 500 micron (5,000–10,000) | 5,000 micron (10,000–20,000)
• Compatible manifold: Testo 557 (confirm with Testo datasheet)
• SKU: 0638 1557

Why Use an External Vacuum Probe?

When evacuating a refrigerant system, measuring vacuum at the manifold can give a misleadingly optimistic reading — the manifold hoses and valves may show a lower micron level than the system itself has achieved. An external vacuum probe placed at or near the system service port gives a more accurate reading of the actual vacuum level in the system, helping you confirm a true deep vacuum before closing valves and releasing the system.

Important: System evacuation and refrigerant handling requires appropriate trade qualifications. Confirm licensing and compliance requirements with the relevant authority in your state or territory before undertaking refrigerant work.

Best For

• HVAC/R technicians using the Testo 557 digital manifold for system evacuation
• Technicians who need more accurate vacuum measurement than a manifold-mounted sensor provides
• Residential and commercial AC and refrigeration system evacuation and commissioning
• Technicians who want to confirm a true deep vacuum before releasing a system

Check Before Ordering

• Confirm this probe is compatible with your specific Testo manifold model — designed for the Testo 557
• Confirm connection type and fitting compatibility with your manifold and system service ports
• System evacuation requires appropriate trade qualifications — confirm licensing requirements in your state or territory
• Confirm warranty terms with HVAC Trade Supply at time of purchase

Frequently Asked Questions

Is the 0638 1557 compatible with Testo manifolds other than the 557?

This probe is designed for the Testo 557. Confirm compatibility with other Testo manifold models against the Testo manufacturer’s current datasheet before ordering.

What is the minimum vacuum level the probe can measure?

The probe measures from 0 microns with 1 micron resolution in the 0–1,000 micron range — suitable for verifying deep vacuum levels during system evacuation.

Do I need a separate vacuum pump to use this probe?

Yes — the probe measures vacuum level; it does not create vacuum. You will need a compatible vacuum pump for system evacuation. Browse our HVAC vacuum pump range for compatible options.

What is the warranty?

Confirm current warranty terms with HVAC Trade Supply at time of purchase. Testo instruments are generally supported by a manufacturer warranty — refer to product documentation for full details.

How fast is delivery across Australia?

We dispatch orders Australia-wide. See our shipping information page for current delivery estimates.

Need a compatible Testo 557 manifold or a vacuum pump? Browse our HVAC test and measurement range or contact our team for advice.