Testo Manifolds for Heat Pump & Refrigeration Systems | Blog

Testo Manifolds: The Go-To Solution for Refrigeration Systems and Heat Pumps

In today's HVAC and industrial service sectors, precision and reliability are everything. Whether you're working on commercial chillers, domestic heat pumps, or industrial cold storage, the tools you use must deliver accurate, reliable data. This is why professionals across the UK trust testo refrigeration gauges like the testo 550i, testo 550s, and testo 558s.

These advanced testo manifolds help technicians streamline service work on refrigeration systems and heat pumps, improve diagnostics, and boost energy efficiency. Backed by Bluetooth connectivity, the testo smart app, and compatibility with testo smart probes, this range of digital gauges sets the standard in performance and ease of use.

Why Testo Manifolds Are Essential for Professionals

Testo refrigeration gauges are designed to replace analogue tools with intelligent, digital solutions. Whether you're commissioning an air source heat pump, maintaining a commercial fridge, or diagnosing a gas boiler system retrofit, Testo manifolds give you the edge.

Each model features robust construction, easy operation, and advanced connectivity options. They're built for harsh environments, designed to handle daily knocks and spills with their IP54 protection rating. The testo 550s is especially popular with HVAC technicians for their clarity and reliable readings, while the testo 550i is ideal for those who prefer app-only operation.

The flagship testo 558s even offers a 4-way valve block, allowing users to perform evacuations directly through the manifold. It also features a colour touchscreen display for faster, more efficient work on refrigeration systems and air conditioning systems.

Discover the perfect Testo manifold for your needs – compare models and find the one that boosts your efficiency and accuracy. The right choice isn’t just a tool, it’s your new go-to partner on every job.

testo 550i Digital Manifold

testo 550s Digital Manifold

testo 558s Digital Manifold

Key Applications in the Field

Heat Pumps: Installation and Servicing

With the rise of air source heat pumps and ground source heat pump systems, there's a growing need for accurate servicing tools. Testo digital manifolds allow heat pump installers to monitor pressures in real time, ensuring that the heating system operates at peak efficiency.

By using Testo refrigeration gauges along with testo 115i Clamp Probes, superheat and subcooling values are automatically calculated. The gauges also help to diagnose refrigerant issues and optimise performance for heat pump run cycles. The result? Smoother installations, better efficiency, and happier heat pump owners.

This level of precision is essential for systems supported under the UK’s boiler upgrade scheme, where efficiency and carbon reduction are key.

Refrigeration Systems: Preventive Maintenance

Commercial and industrial refrigeration systems demand consistent performance. From cold rooms in restaurants to chillers in manufacturing plants, system failure can lead to costly spoilage and downtime.

Testo digital manifolds are used to perform regular checks, including leak tests and pressure monitoring. Built-in calibration protocol features help technicians stay compliant with service standards.

In one recent project, a facilities team used the testo 550i and testo Smart Probes to assess pressure drops across a large cooling system. Their findings led to the discovery of a blocked expansion valve, which was resolved quickly thanks to accurate diagnostics.

Transitioning from Fossil Fuels

As buildings shift away from fossil fuel-based systems, the focus is on efficient, low-carbon heating and cooling. Whether retrofitting a hot water cylinder to work with a heat pump, or replacing an old gas boiler, accurate diagnostics are critical.

Testo refrigeration gauges support this transition. For example, when swapping a gas boiler for a ground source heat pump, a technician can use the testo 550s to verify refrigerant charge, ensure proper flow, and balance the heating system.

This helps ensure continuously high performance and long-term reliability.

Choosing the Right Testo Manifold

• testo 550i: The most compact option. Fully app-controlled with no built-in screen. Lightweight, reliable, and perfect for tech-savvy pros.
• testo 550s: Enhanced display, Bluetooth connectivity, and compatibility with wireless probes. Perfect for advanced diagnostics.
• testo 558s: Top-of-the-range digital manifold. Includes a 4-way valve block, 0.25% full scale accuracy, and excellent logging features. Built for demanding service and commissioning tasks.

Each of these Testo manifolds is built to support high-efficiency heat pumps and complex refrigeration systems, making them invaluable for today’s HVAC professionals.

Why Work With Acutest?

At Acutest, we supply the full range of Testo refrigeration gauges along with expert advice and support. Whether you're a seasoned engineer or a new heat pump installer, we’re here to help you choose the right tools and get the most from your measuring instruments.

We offer:

• Free online and in-person demonstrations
• Expert support on compatibility and best practices

Get in Touch

Ready to upgrade your diagnostic toolkit? Contact Acutest today to book a demonstration of the testo 550i, testo 550s, or testo 558s. Discover how Testo manifolds can help you deliver faster, more accurate service on heat pumps and refrigeration systems. Explore our site for datasheets, real-world case studies, and the latest updates in refrigeration and air conditioning technology.

📢  New Option now available Testo SightGlass

"What is Testo SightGlass?

The term "Testo Sightglass" refers to the integrated sight glass feature found in certain Testo Digital Manifold gauges. This component allows HVAC/R technicians to visually monitor the flow of refrigerant within a system, aiding in diagnostics and system assessments."

So what are the options for Testo Digital Manifolds:

The various models of the Testo 550i:

• (0564 2550 02) Testo 550i Manifold ONLY
• (0564 2550) Testo 550i Digital Manifold (+Sightglass)
• (0564 3550 02) Testo 550 Digital Manifold Smart Kit
• (0564 3550) Testo 550i Digital Manifold Smart Kit (+Sightglass)
• (300564 3550 02) Testo 550i - Digital Manifold Heat Pump Kit
• (300564 3550 03) Testo 550i - Digital Manifold Heat Pump Kit (+Sightglass)

What comes with the Testo 550i (0564 2550 02)?

• Testo 550i Digital 2-Way Manifold
• Batteries (3 x AAA)
• Calibration Protocol
• Instruction Manual
• Testo Smart App (free download)

What extra comes with the Smart Kit (0564 3550 02)?

Extra to the standard model:

• 2 x Testo 115i Wireless Bluetooth Pipe Clamp Thermometers
• Carry Case

What extra comes with the Heat Pump Kit (300564 3550 02)?

Extra to the standard model:

• 2 x Testo 115i Wireless Bluetooth Pipe Clamp Thermometers
• 1 x Testo 770-3 Clamp Meter
• Carry Case

Testo 550i SightGlass Options:

0564 2550 / 0564 3550 / 300564 3550 03

The various models of the Testo 550s:

• (0564 5501 02) 550s Digital Manifold Basic Kit (2-Way Valve Block)
• (0564 5501) 550s Digital Manifold Basic Kit (2-Way Valve Block; with Sightglass)
• (0564 5502 02) 550s Digital Manifold Smart Kit (2-Way Valve Block)
• (0564 5502) 550s Digital Manifold Smart Kit (2-Way Valve Black; with Sightglass)
• (0564 5503 02) 550s Digital Manifold Smart Kit (2-Way Valve Block; Hoses)
• (0564 5503) 550s Digital Manifold Smart Kit (2-Way Valve Block; Hoses; Sightglass)
• (300654 5502 02) 550s Digital Manifold Heat Pump (2-Way Valve Block)
• (300654 5502 03) 550s Digital Manifold Heat Pump (2-Way Valve Block; Sightglass)

What comes with the Testo 550s (0564 5501 02)?

Testo 550s Digital Manifold

• Testo 550s Digital 2-Way Manifold
• Batteries (3 x AA)
• Calibration Protocol
• Instruction Manual
• Testo Smart App (free download)

What extra comes with the Smart Kit (0564 5502 02)?

Testo 550s Digital Manifold – Smart Kit

Extra to the standard model:

• 2 x Testo 115i Wireless Bluetooth Pipe Clamp Thermometers
• Carry Case

What extra comes with the Heat Pump Kit (300564 5502)?

Testo 550s Digital Manifold – Heat Pump Kit

Extra to the standard model:

• 2 x Testo 115i Wireless Bluetooth Pipe Clamp Thermometers
• 1 x Testo 770-3 Clamp Meter
• Carry Case

Testo 550s SightGlass Options:

0564 5501 / 0564 5502/ 0564 5503 / 300654 5502 03

The various models of the Testo 558s:

• (0564 5582 02) 558s Smart Vacuum Kit
• (0564 5582) 558s Smart Vacuum Kit (with Sightglass)
• (0564 5583 02) 558s Smart Vacuum Kit (with hoses)
• (0564 5583) 558s Smart Vacuum Kit (with hoses; Sightglass)
• (0564 5585 02) 558s Heat Pump Kit
• (0564 5587 03) 558s Heat Pump Kit (with Sightglass)
• (0564 5586 02) 558s Heat Pump Kit (with hoses)
• (0564 5588 03) 558s Heat Pump Kit (with hoses; Sightglass)

What comes with the Testo 558s (0564 5582 02)?

Testo 558s Digital Manifold

• Testo 558s Digital 4-Way Manifold
• Batteries (4 x AA)
• Calibration Protocol
• Instruction Manual
• Testo Smart App (free download)
• With hoses if required (0564 5583)

What extra comes with the Heat Pump Kit (0564 5585 02)?

Testo 558s Digital Manifold – Heat Pump Kit

Extra to the standard model:

• 2 x Testo 115i Wireless Bluetooth Pipe Clamp Thermometers
• 1 x Testo 770-3 Clamp Meter
• Carry Case
• With hoses if required (0564 5586 02)

Testo 558s SightGlass Options:

0564 5582 / 0564 5583 / 0564 5587 03 / 0564 5588 03