UNI-T UT366A for Data Centre Differential Pressure and Cooling Airflow Checks Malaysia

Data centres depend on controlled cooling airflow to remove heat from servers and other critical equipment. When air pressure is not distributed correctly, cooled air may bypass the server racks, escape through unwanted openings or fail to reach high-load areas.

The UNI-T UT366A Digital Manometer can support data-centre facility teams by measuring gauge pressure, differential pressure and duct air velocity with an optional Pitot tube.

Why Differential Pressure Matters

Air moves from an area of higher pressure towards an area of lower pressure. This pressure difference influences how cooled air travels through a data-centre space.

Differential-pressure measurement can help technicians investigate:

Pressure below and above a raised floor
Pressure across an air filter
Pressure before and after a cooling coil
Supply and return duct pressure
Pressure between a server room and adjacent space
Pressure changes across containment doors
Airflow restrictions inside ventilation systems

The required pressure condition depends on the facility design. Measurements should be compared with the data centre’s operating specification rather than a single general target.

UT366A Pressure Measurement

The UT366A has separate P1 and P2 pressure ports and can measure:

Positive pressure
Negative pressure
Gauge pressure
Differential pressure
Independent P1 pressure
Independent P2 pressure

Its pressure range is ±15.00 kPa, with a specified accuracy of ±0.5% full scale at 25°C.

The instrument also supports multiple pressure units, including:

kPa
mbar
bar
psi
mmH₂O
inH₂O
hPa

Technicians can select the unit used in the facility’s commissioning or maintenance documentation.

Checking Raised-Floor Pressure

In data centres using raised-floor cooling, conditioned air is supplied into the underfloor space before passing through perforated tiles or grilles.

Pressure measurements at different underfloor locations can help identify:

Uneven pressure distribution
Air leakage
Obstructions beneath the floor
Poorly positioned floor openings
Insufficient pressure in distant areas
Changes after equipment or cable installation

Readings should be taken at repeatable locations under similar cooling-system conditions.

A single measurement cannot represent the pressure condition of the entire floor. Create a measurement map and compare values across several points.

Checking Air Filter Pressure Drop

Dirty filters can restrict airflow through computer-room air-conditioning or air-handling equipment.

To check filter pressure drop:

Locate the approved pressure points before and after the filter.
Connect the pressure hoses securely.
Select differential-pressure measurement.
Confirm the correct pressure unit.
Allow the cooling unit to operate steadily.
Record the reading.
Compare the result with the filter or equipment manufacturer’s specification.

A rising pressure drop may indicate increasing filter restriction. A very low reading may indicate a missing filter, air bypass, low fan speed or an incorrect connection.

Checking Pressure Across Cooling Components

The UT366A may also be used to compare pressure across accessible HVAC components such as:

Cooling coils
Fans
Dampers
Duct sections
Heat-exchanger sections
Air-handling components

An unusual pressure difference may help locate a restriction or system change. However, the reading must be interpreted together with airflow, fan speed, filter condition and equipment design.

Measuring Duct Air Velocity

When paired with the optional UNI-T Pitot tube, the UT366A can measure air velocity inside a duct.

The compatible Pitot tube is:

Approximately 350 mm long
8 mm in diameter
Manufactured from 304 stainless steel
Connected through separate black and white silicone hoses

For representative measurements, take readings at multiple points across the duct rather than relying only on the centre value.

Average air velocity can be combined with the internal duct area to estimate air volume.

Investigating Hot Spots

A high rack-inlet temperature does not automatically mean the cooling system has insufficient total capacity.

Possible causes include:

Uneven underfloor pressure
Blocked perforated tiles
Air leakage
Open cable cut-outs
Incorrect tile placement
Short-circuiting between cold and hot air
Poor rack containment
Obstructed supply ducts
Incorrect fan operation

Pressure and airflow measurements help technicians investigate the air-delivery path. Temperature measurements are still required to confirm the actual thermal condition at the rack.

Cold-Aisle and Hot-Aisle Containment

Containment systems are designed to reduce mixing between supply and exhaust air. Pressure checks can help identify whether air is moving in the intended direction.

Measurement points may include:

Inside and outside the cold aisle
Inside and outside the hot aisle
Across containment doors
Around ceiling return paths
Near unsealed floor or cable openings

Opening a door during measurement can change the pressure condition. Record whether containment doors were open or closed when each reading was taken.

Create Repeatable Measurement Records

For useful trend analysis, record:

Date and time
Cooling-unit operating condition
Measurement location
P1 connection point
P2 connection point
Selected pressure unit
Pressure or air-velocity reading
Rack or room identification
Any recent system changes
Corrective action taken

Repeat measurements under similar load and cooling conditions whenever possible.

Common Measurement Errors

Unreliable data-centre pressure readings may be caused by:

Loose or leaking hoses
Reversed P1 and P2 connections
Measuring beside direct supply airflow
Moving doors during testing
Variable fan-speed changes
Blocked pressure points
Incorrect pressure units
Comparing readings taken under different operating conditions

Before concluding that a cooling problem exists, check the instrument setup and repeat the measurement.

Who Can Use the UT366A?

The UT366A is suitable for:

Data-centre facility teams
HVAC maintenance contractors
Mechanical and electrical contractors
Testing and commissioning teams
Building-management personnel
Cooling-system service companies

It can support pressure and airflow investigations in data centres located in Selangor, Kuala Lumpur, Johor, Penang and other parts of Malaysia.

Select the Correct Data Centre Test Instrument

The UT366A measures pressure and optional duct air velocity. A complete cooling assessment may also require temperature, humidity, electrical and thermal-imaging instruments.

For assistance selecting the UT366A for a data-centre pressure or cooling-airflow application, WhatsApp MTM Precision with photos of the measurement area and a description of the required test points.

MTM Precision Sdn Bhd

Showroom & Service Centre:
No. 29-1 & 29-2, Jalan Bandar 18,
Pusat Bandar Puchong,
47160 Puchong, Selangor, Malaysia

Tel: 03-8080 7172
WhatsApp: +6016-660 7346
Email: mtmpre@yahoo.com
Website: www.mtmpre.com.my