UNI-T UT366A Hose and Pitot Tube Maintenance Guide Malaysia

Accurate pressure and air-velocity measurements depend on more than the UNI-T UT366A Digital Manometer itself. The pressure hoses and optional Pitot tube must also remain clean, dry, undamaged and correctly connected.

A leaking hose or blocked Pitot tube can produce incorrect results even when the UT366A is operating normally.

Inspect the Hoses Before Every Test

Check each pressure hose for:

Cracks
Punctures
Loose connections
Hardened material
Flattened sections
Kinks
Internal blockage
Moisture
Oil or chemical contamination
Heat damage

Bend the hose gently while inspecting it. Small cracks may only become visible when the material is flexed.

Replace a damaged hose instead of using tape as a permanent repair.

Check the Hose Connections

The hose should fit securely onto:

The UT366A pressure port
The pressure-test point
The Pitot tube connection
Any approved adaptor

A loose connection can allow air leakage and cause:

Low readings
Unstable values
Slow pressure response
Different results during repeated tests
Failure to return to zero

Do not force an undersized hose onto the pressure port, as excessive force may damage the fitting.

Keep the Hoses Separate

The compatible UNI-T Pitot tube uses:

One black silicone tube
One white silicone tube

Using different colours helps technicians identify the two pressure paths.

For consistent work:

Assign each colour to the correct Pitot tube connection
Avoid crossing the hoses
Label them when necessary
Record the P1 and P2 arrangement
Use the same configuration during repeated measurements

Reversed connections may change the displayed pressure sign.

Check for Internal Moisture

Moisture inside a pressure hose can restrict or delay pressure transmission.

It may enter during testing in:

Humid ducts
Condensing air systems
Wet exhaust lines
Cooling systems
Boiler or furnace applications
Outdoor ventilation systems

Symptoms may include:

Slow response
Unstable reading
Pressure remaining after disconnection
Different responses between P1 and P2
Failure to return near zero

Disconnect a contaminated hose from the UT366A before handling it. Do not allow liquid to drain into the instrument’s pressure ports.

Do Not Blow into the UT366A

Do not use:

Compressed air
High-pressure pumps
An air gun
Direct mouth pressure

to clear the UT366A pressure ports.

The instrument’s measurement range is ±15.00 kPa. Uncontrolled pressure may exceed the specified range and damage the internal sensor.

Any hose-cleaning method should be performed with the hose fully disconnected from the instrument.

Inspect the Pitot Tube Openings

The optional Pitot tube has openings used to detect total and static pressure.

Inspect for:

Dust
Insects
Oil
Condensation
Tape residue
Bent metal
Damaged openings
Corrosion
Process contamination

A blocked opening can cause incorrect air-velocity readings.

Do not enlarge the openings or insert sharp objects that may damage their shape.

Clean the Pitot Tube Carefully

Before cleaning:

Disconnect both hoses.
Remove the Pitot tube from the duct.
Confirm that it has cooled to a safe temperature.
Identify the type of contamination.
Follow the applicable maintenance procedure.

Wipe the external 304 stainless-steel surface using a suitable soft cloth.

Avoid cleaning agents that could:

Corrode the stainless steel
Leave residue inside the pressure passages
Damage the silicone hoses
Create a safety risk in the next application

The cleaning method should be suitable for the material previously measured.

Do Not Use the Pitot Tube in Unsuitable Media

The UT366A Pitot tube is intended for airflow measurement.

Do not assume it is suitable for direct measurement of:

Steam
Liquid
Corrosive gas
High-temperature flue gas
Combustible process gas
Chemically contaminated flow
Pressurised gas above the instrument range

Additional protective equipment or a different instrument may be required.

Check Pitot Tube Alignment

A Pitot tube must face directly into the airflow.

Before taking readings:

Confirm the airflow direction
Insert the tube through a suitable access point
Keep the front opening facing upstream
Hold the tube steadily
Avoid contact with the duct wall
Take readings at several positions
Allow each reading to stabilise

A bent tube or damaged tip may make correct alignment difficult.

Store the Hose Without Sharp Bends

After use:

Remove the hose gently from the fittings
Wipe away external dirt
Allow the hose to dry
Coil it loosely
Avoid tight knots
Keep it away from sharp tools
Avoid placing heavy items on it
Store it away from heat and sunlight

A tightly folded hose may develop a permanent restriction.

Protect the UT366A Pressure Ports

When the instrument is not in use:

Disconnect the hoses
Keep the pressure ports clean
Store the unit in its carrying bag
Prevent tools from pressing against the ports
Avoid dust and moisture
Keep it away from oil and chemicals
Do not leave it inside a hot vehicle
Remove batteries for extended storage when appropriate

Damaged pressure ports may require repair rather than calibration.

Perform a Leak Check

If a reading appears lower or less stable than expected:

Inspect the hose visually.
Check both connections.
Replace the suspected hose with a known good hose.
Repeat the measurement under the same condition.
Compare the results.

Do not use an uncontrolled high-pressure source to search for leakage.

Confirm Zero Before Measurement

Before connecting to the test points:

Place the UT366A in a stable environment
Keep both pressure ports open
Move away from direct airflow
Allow the display to settle
Confirm the selected pressure unit
Check the battery condition

If the reading remains offset with both ports open, further checking may be required.

Create an Accessory Inspection Record

For frequently used equipment, record:

Inspection date
Hose condition
Pitot tube condition
Cleaning performed
Replaced accessories
Moisture exposure
Heat exposure
Measurement problems
Technician’s name

This helps identify recurring accessory problems before they affect site measurements.

When Should the Hose Be Replaced?

Replace the hose when it shows:

Cracking
Leakage
Hardening
Permanent flattening
Heat damage
Chemical damage
Loose fit
Internal contamination that cannot be removed
Repeated unstable readings

A low-cost hose can affect the performance of the complete measurement system.

When Should the Pitot Tube Be Replaced or Inspected?

Arrange inspection when:

The tube is bent
The tip is damaged
The pressure openings are deformed
Internal blockage cannot be removed safely
Corrosion is visible
The tube was exposed to unsuitable chemicals
Air-velocity readings remain incorrect after checking the hoses and instrument

Do not attempt to reshape a damaged Pitot tube without confirming that its measurement geometry remains correct.

Accessory and Instrument Enquiry

For assistance with the UNI-T UT366A, pressure hoses or compatible Pitot tube, WhatsApp MTM Precision with clear photos of the instrument, accessories and measurement application.

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