Fieldpiece CAT85 Combustion Analyzer with HydroCycle

  • Fieldpiece CAT85 Combustion Analyzer with HydroCycle
  • Fieldpiece CAT85 Combustion Analyzer with HydroCycle
  • Fieldpiece CAT85 Combustion Analyzer with HydroCycle
  • Fieldpiece CAT85 Combustion Analyzer with HydroCycle
MSRP: $1,955.00
Price: $1,670.25
— You save $284.75


Fieldpiece CAT85 Combustion Analyzer with HydroCycle

Built Tough Enough for any Heating Job

The Fieldpiece CAT85 Combustion Analyzer HC provides a hassle-free solution for technicians to get the job done quickly, easily, and safely while improving system efficiency. Accurate sensors of O2, CO, pressure, and temperature along with powerful trending, provide key insight into equipment performance. SensorVault technology seals to prolong sensor life. A large, high-contrast 5.5" touchscreen display helps you easily view measurements. Save your customer data with dedicated fields for client information and create trend reports for advanced diagnosis. Live draft pressure measurement maintains accuracy throughout your combustion test. Dual manometer ports are also included for convenience. The combustion probe uses a patent pending HydroCycle pump to return condensate back into the flue - no more water trap hassles!

Key Features and Benefits

  • Accurately measure O2, CO, CO2, draft pressure
  • Built-in manometer means one less tool to carry
  • Automatically separates and returns accumulated water to the flue using the patent pending HydroCycle Pump technology.
  • Lower cost of ownership with four-year sensor warranty
  • Large 5.5" touchscreen display with one-touch power on
  • Field-replaceable sensors to maximize uptime
  • Troubleshoot while running analysis with live draft pressure
  • Patent pending SensorVault technology prolongs sensor life
  • Connect with Job Link System App, industry-leading 1000' wireless range
  • USB-C chargeable while in use
  • 1 Year Manufacturer Device Warranty
  • 4 Year Manufacturer Sensor Warranty

Breakthrough Innovation HydroCycle

The CAT85 does not have a water trap. Instead, flue gas condensate is automatically pumped back out of the front of the probe at a regular interval. Point the probe downwards as you remove it to empty any remaining condensate before storing. Also, the CAT85 offers a built-in manometer so you can carry one less tool.

Breakthrough Innovation SensorVault

The SensorVault technology of the power button unseals sensors when powering on and and seals the sensors when powering off. SensorVault technology prolongs the life of sensors, but they eventually need to be replaced. When it does come time to replace sensors, CAT85 makes it quick and painless. Replacement sensors have calibration data built-in and do not require calibration. When a sensor's life drops below 5%, a notification appears during startup to inform you it's time to replace it. You can view estimated remaining life at any time in SETTINGS.

Simplicity Redefined

Featuring a high contrast, 5.5" touchscreen display, the CAT85 makes it easy to view measurements, whether your jobsite is a dimly lit basement or bright rooftop. You can also save your customer data with dedicated fields for client information. If you require advanced diagnoses, a live trend report is available with O2, CO and CO2 readings.

Reliable & Rugged

The CAT85 can tackle any jobsite conditions with its durable construction and rubberized casing. The magnetic back lets you work hands-free and the padded hardline carrying case includes multiple inserts for accessories.

Rugged Construction

Durable construction and rubberized casing make the CAT85 tough enough to tackle any jobsite conditions. The magnetic back also lets you work hands-free and the padded hardline carrying case has multiple inserts for accessories.

Jobsite Documentation

Seamlessly connect to Fieldpiece Job Link System App to view trends, draft pressure, and customer details, all with industry-leading 1000' wireless range. A wireless printer is also available for jobsites that require documentation printouts.


General Specs
Display Touchscreen TFT LCD (5.5 in diagonal)
Probe Size 10.7 in (272 mm) length, 0.32 in (8.0 mm) diameter
Accuracy Stated accuracies at 23°C ±5°C, <75% R.H.
Manometer Ports 2 connectors (P1, P2) for flex tubing
(4.5mm to 8.0mm ID, not included)
Battery Type 3.7 VDC (nominal), 6400mAh, non-replaceable
Battery Life 7 hours typical (pump running 80% of the time)
Charge Time < 7 hours typical @ 5V/2A DC power (power adapter not included)
Charging Port USB-C (Usable when connected to power)
Memory 1000 jobs (approx.)
Warm Up Time 45 seconds (90 seconds near freezing)
Operating Environment 14°F to 104°F (-10°C to 40°C); < 75% RH (non-condensing)
Storage Temperature -4°F to 140°F (-20°C to 60°C); < 80% RH
Weight 44.25 oz (1255 g) with probe
Wireless Range 1000 feet (305 meters)
Fuel Types Natural Gas, Propane (LPG), Oil #2 (Light), Oil #6 (Heavy), Biofuel, Coal, Coal Town Gas, Coking Oven Gas, KOKS, Custom (x3)
Manufacturer Warranty 1 year (4 years sensors only)
Job Link System Minimum BLE 4.0 devices running iOS 7.1 or Android™ Kitkat 4.4
Latest compatibility at
Sensor Type Response Time Max Overload
Temperature Type K rod thermocouple (fixed) < 30 seconds (T90)
Oxygen (%) Electrochemical (replaceable) < 30 seconds (T90) 30% Oxygen
Carbon Monoxide (PPM) Electrochemical (replaceable) < 90 seconds (T90) 10000 ppm Carbon Monoxide
Pressure Probe (inWC, torr, Pa) Piezoresistive pressure sensor < 10 seconds (T90) 4.0 inWC will cause damage
Pressure Ports (inWC, torr, Pa) Silicon pressure sensors < 10 seconds (T90) 11.6 psig (321 inWC) causes damage
Testing Parameters
Range Best Resolution Accuracy
Stack Temperature 32 to 752°F; 0 to 400°C 0.1°F; 0.1°C ±2.5°F [32°F to 212°F], ±(3.6°F or 1.5%rdg) [213°F to 752°F];
±1.4°C [0°C to 100°C], ±(2.0°C or 1.5%rdg) [101°C to 400°C]
Oxygen O2 0 to 21 vol.% 0.1 vol.% ±0.3 vol.%
Carbon Monoxide CO 0 to 4000 ppm 1 ppm ±20 ppm [0 to 400 ppm], ±5%rdg [401 to 2000 ppm], ±10%rdg [2001 to 4000 ppm]
Draft Pressure 0 to ±0.8 inWC 0.01 inWC ±0.02 inWC
CO Air Free (Calculated) 0 to 4000 ppm 1 ppm
CO2 (Calculated) 0 to CO2max vol.% 0.1 vol.%
Excess Air (Calculated) 0 to 999% 0.1%
Efficiency (Calculated) 0 to 100% 0.1%
qA (Calculated) 0 to 25% 0.1%
Dew Point (Calculated) 32 to 212°F; 0 to 100°C 0.1°F; 0.1°C
Primary Air Temp 32 to 212°F; 0 to 100°C 0.1°F; 0.1°C ±2.5°F [32°F to 212°F];
±1.4°C [0°C to 100°C]
Ambient CO 0 to 200 ppm 1 ppm ±20 ppm
Manometer 0 to ±40 inWC 0.01 inWC ±0.2 inWC [0 to ±20 inWC], ±1%rdg [±(20.1 to 40.0 inWC)]
Fuel Pressures 0 to 40 inWC 0.01 inWC ±0.2 inWC [0 to 20 inWC], ±1%rdg [20.1 to 40.0 inWC]


  • (1) CAT85 Combustion Analyzer HC (including probe)
  • (1) Carrying case - ANC85
  • (2) Cones - RCONE3
  • (10) Filters - RFC10
  • (1) USB cable
  • (1) Manual


Software / App

Download the Fieldpiece Job Link App for your Android or iOS devices

Google Play Google Play

Link Your Tools. Link Your Jobs
Job Link. More than just measurements.

The Job Link System works with all Fieldpiece wireless tools from clamps to probes to digital manifolds, and integrates all of their functionality seamlessly. Job Link increases your level of professionalism on every job and in the back office by allowing you to not only eliminate your clipboard but also virtually adding another technician to the job because you can be in more than one place at a time. Reduce callbacks and increase efficiencies with reliable and trusted system measurements, diagnostics, and reporting!

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