Large water systems often require more drawdown volume and pressure stability than a single vessel can provide.
Installing multiple Wates pressure vessels in parallel is a proven method to:

• Increase total effective drawdown
• Reduce pump cycling
• Improve pressure stability in fluctuating demand systems
• Provide redundancy for maintenance

This guide explains how to correctly design, install, and commission parallel pressure vessel arrangements.

2. When Parallel Installation Is Required
Parallel installation is recommended when:

• Required vessel size exceeds practical single-tank limits
• Pump cycling remains high even with a correctly sized single vessel
• System serves large or variable demand loads
• Space constraints prevent installing one large tank
• Redundancy is required for critical facilities (hotels, hospitals, towers)

Typical applications include:

• High-rise booster pump sets
• Multi-pump VFD systems
• Commercial complexes and malls
• Industrial water supply systems

3. Benefits of Installing Vessels in Parallel

• Higher total drawdown volume without extreme tank sizes
• Even pressure buffering across the system
• Reduced pump starts per hour
• Operational redundancy (one vessel can be isolated for service)
• Flexible future expansion

4. Basic Principle of Parallel Vessel Operation
When vessels are connected in parallel:

• All vessels experience the same system pressure
• Drawdown volume is shared equally
• Each vessel absorbs part of the pressure fluctuation
• The system behaves like one larger vessel--only if installed correctly

Incorrect piping or unequal pre-charge will cause one vessel to work harder than others.

5. Design Rules for Parallel Installation
5.1 Use Identical Vessel Models

• Same capacity
• Same pressure rating
• Same bladder type

Mixing different sizes or ratings leads to uneven loading and premature failure.

5.2 Equal Pipe Lengths and Diameters

• Each vessel branch must have similar pipe length and diameter
• Avoid one vessel being “closer” hydraulically than others
• This ensures equal flow and pressure sharing

5.3 Common Discharge Header Connection

• All vessels must connect to the same discharge manifold
• Never connect vessels to individual pump outlets

6. Step-by-Step Installation Procedure
Step 1: Determine Total Required Drawdown

• Calculate required drawdown based on pump flow, cut-in/cut-out pressure, and allowed starts/hour
• Divide total required volume across multiple vessels

Example:

• Required drawdown: 600 L
• Use three 300 L vessels in parallel (effective shared drawdown)

Step 2: Prepare the Manifold Header

• Install a properly sized main header (steel or stainless steel)
• Header must handle total flow without pressure loss
• Provide adequate supports to avoid pipe stress

Step 3: Install Branch Connections
Each vessel branch should include:

• Isolation valve
• Union or flange connection
• Drain valve (recommended)

This allows individual vessel isolation and servicing.

Step 4: Mount the Vessels

• Vertical orientation preferred for large systems
• Place vessels on level floor or approved stands
• Ensure vessels are aligned and fully supported
• No vessel weight should be carried by pipework

Step 5: Set Pre-Charge Pressure (Critical)

• All vessels must have identical pre-charge pressure
• Pre-charge rule:
  • Fixed-speed pumps → cut-in − 0.2 to 0.5 bar
  • VFD systems → 0.5–1.0 bar below set pressure

Pre-charge must be set before filling the system with water.

Step 6: Open Isolation Valves and Fill System

• Open all vessel isolation valves slowly
• Allow vessels to fill evenly
• Check pressure gauge for smooth pressure rise

Step 7: Commission and Balance

• Start pumps and observe pressure behavior
• Open downstream outlets and confirm equal drawdown
• Ensure no single vessel empties faster than others

7. Using Parallel Vessels with Multi-Pump and VFD Systems
Parallel vessels are especially effective with:

• Multi-pump booster sets
• VFD-controlled systems with fluctuating demand

Benefits include:

• Improved pressure sensor stability
• Reduced VFD hunting
• Smoother pump sequencing

All vessels must be installed close to the pressure sensor for best results.

8. Common Installation Mistakes to Avoid

• Different vessel sizes in the same parallel group
• Unequal pre-charge pressures
• One vessel connected closer to header than others
• No isolation valves on individual vessels
• Undersized header piping
• Allowing pipe strain on vessel connections

9. Maintenance Advantages of Parallel Installation

• Individual vessels can be isolated for bladder replacement
• System remains operational during maintenance
• Easier future capacity expansion
• Reduced downtime for critical facilities

Recommended maintenance:

• Check pre-charge every 6–12 months
• Inspect isolation valves and drains
• Rotate servicing between vessels if needed

10. UAE / GCC Installation Considerations

• High ambient temperatures require shaded, ventilated pump rooms
• Larger systems benefit from multiple medium vessels rather than one very large tank
• Use corrosion-resistant fittings in coastal areas
• Pre-charge checks should be more frequent (every 3–6 months)

11. Final Inspection Checklist
Before handover, verify:

• All vessels are identical and correctly mounted
• Pre-charge pressure equal across all tanks
• Isolation and drain valves installed on each branch
• No pipe stress or vibration transfer
• Stable pressure under varying demand
• Pump cycling within design limits

Installing multiple Wates pressure vessels in parallel is the most reliable solution for large and high-demand water systems.
When designed and installed correctly, parallel vessels deliver superior pressure stability, reduced pump wear, and long-term operational flexibility. For more info contact Wates Pressure Vessel Supplier in UAE or call us at +971 4 2522966.

Small-capacity pressure vessels (typically 8–100 L) are widely used in domestic booster pumps, well systems, RO units, and compact pump rooms.
Choosing between wall-mount and floor-mount installation for a Wates pressure vessel affects:

• Structural safety
• Ease of maintenance
• Long-term vessel life
• Pipe stress and vibration control

This guide explains when to use wall-mounted or floor-mounted installation and how to choose the correct option.

2. What Is Considered a “Small” Wates Pressure Vessel?
Small vessels are typically:

• Capacity: 8 L, 12 L, 18 L, 24 L, 50 L, up to ~100 L
• Common applications:
  • Domestic booster pumps
  • Well pump systems
  • Under-sink or cabinet installations
  • RO and filtration systems
  • Small irrigation or garden systems

These vessels are light enough to be wall-mounted only if designed and supported correctly.

3. Wall-Mount Installation of Small Wates Vessels
3.1 When Wall-Mounting Is Suitable
Wall-mount installation is appropriate when:

• Floor space is limited
• Installation is inside cabinets, cupboards, or service shafts
• Vessel size is small (usually ≤ 50 L, sometimes up to 80 L with proper brackets)
• Wall structure is strong (concrete or load-bearing masonry)

3.2 Wall-Mounting Requirements
To safely wall-mount a Wates vessel:

• Use manufacturer-approved wall brackets or cradles
• Ensure wall is solid concrete or reinforced block
• Use heavy-duty anchor bolts (not plastic plugs)
• Ensure pipework is independently supported

Never rely on pipe connections to carry vessel weight.

3.3 Advantages of Wall-Mount Installation

• Saves valuable floor space
• Cleaner, compact installation
• Easier to integrate into cabinets or service boxes
• Reduced risk of floor moisture corrosion

3.4 Limitations and Risks

• Not suitable for drywall or gypsum partitions
• Limited maximum vessel size
• Incorrect anchoring can cause vibration damage or wall failure
• More difficult bladder replacement if clearance is poor

4. Floor-Mount Installation of Small Wates Vessels
4.1 When Floor-Mounting Is Preferred
Floor-mount installation is recommended when:

• Floor space is available
• Vessel capacity is 50 L or larger
• Pump room layout allows vertical installation
• Long-term maintenance access is important

4.2 Floor-Mounting Requirements

• Place vessel on a flat, level surface
• Ensure full contact of base ring with floor
• Use anti-vibration rubber pads if pump is nearby
• Pipework must align naturally without side load

4.3 Advantages of Floor-Mount Installation

• Better long-term structural stability
• No wall load concerns
• Easier bladder replacement and servicing
• Suitable for future system upgrades

4.4 Limitations

• Requires dedicated floor space
• Not ideal for tight cabinets or under-sink areas
• Must be protected from water pooling on floors

5. Choosing Between Wall-Mount and Floor-Mount
Key Selection Factors

• Vessel size and weight
• Wall strength and material
• Available floor space
• Maintenance access needs
• Vibration level from pump
• Installer safety and long-term reliability

General rule:
If in doubt, floor-mounting is always safer.

6. Typical Installation Examples
Wall-Mount Suitable Applications

• Under-sink booster pump systems
• Small RO units
• Compact villa pump cabinets
• Light-duty well pump control rooms

Floor-Mount Suitable Applications

• Domestic booster pump rooms
• Well pump pressure tanks
• Small commercial pump sets
• Systems with higher vibration or pressure variation

7. Common Installer Mistakes to Avoid

• Wall-mounting vessels without proper brackets
• Fixing vessels to drywall or weak partitions
• Allowing pipework to support vessel weight
• Wall-mounting oversized tanks
• Mounting vessels with no clearance for air valve access
• Floor-mounting on uneven or wet surfaces

8. UAE / GCC Installation Considerations

• Wall-mounted vessels must be protected from heat buildup in small cabinets
• Floor-mounted vessels should not sit directly on hot concrete rooftops
• High ambient temperature increases stress on wall brackets over time
• Coastal areas require corrosion-resistant fasteners and brackets

9. Installer Checklist
Before finalizing installation, confirm:

• Vessel capacity suits mounting method
• Correct brackets or base support used
• Wall or floor surface is structurally sound
• Pipework is stress-free and aligned
• Air valve and isolation valve are accessible
• Vessel is protected from heat and moisture

Both wall-mount and floor-mount installation options are suitable for small Wates pressure vessels when applied correctly.
Wall-mounting saves space and works well for compact systems, while floor-mounting offers superior stability and serviceability. For more info contact Wates Pressure Vessel Supplier in UAE or call us at +971 4 2522966.

Variable Speed Drive (VFD) pump systems are designed to maintain constant pressure with high energy efficiency, but they still require pressure vessels for stable and reliable operation.
A properly installed Wates pressure vessel prevents pressure hunting, protects the VFD controller, and ensures smooth pump modulation under low-demand conditions.
This guide explains how to correctly install Wates pressure vessels in VFD-controlled pump systems.

2. Why VFD Systems Still Need Pressure Vessels
A common misconception is that VFD pumps eliminate the need for pressure vessels. In reality, vessels are essential to:

• Absorb minor demand changes without forcing speed fluctuations
• Prevent pressure sensor instability and “hunting”
• Maintain standby pressure when demand is very low or zero
• Reduce wear on pump bearings and seals
• Provide buffer volume during sensor delay or power fluctuations

Without a pressure vessel, VFD systems often suffer from oscillation, noise, and premature component failure.


3. How a Pressure Vessel Works with a VFD Pump
In a VFD system:

• The pressure sensor continuously sends feedback to the controller
• The pump speed adjusts to match system demand
• The pressure vessel absorbs short-term pressure changes

The vessel acts as a hydraulic shock absorber, smoothing pressure signals so the VFD can respond gradually rather than aggressively.

4. Correct Location for the Pressure Vessel in a VFD System
4.1 Always Install on the Discharge Side

• The vessel must be connected to the main discharge manifold, never on suction.
• This ensures it sees the same pressure as the pressure sensor.

4.2 Install Close to the Pressure Sensor

• Ideally, the vessel and pressure transmitter should be on the same header.
• Distance between vessel and sensor should be minimal to avoid signal delay.

4.3 Never Install on Individual Pump Outlets

• In multi-pump VFD systems, vessels must be connected to the common discharge header, not to individual pumps.

5. Step-by-Step Installation Procedure
Step 1: Confirm System Design Parameters
Before installation, confirm:

• Set pressure (constant pressure value)
• Maximum allowable system pressure
• Number of pumps and control sequence
• Vessel pressure rating (10 bar, 16 bar, etc.)

Step 2: Select Correct Vessel Size

• VFD systems typically require larger vessels than fixed-speed systems for signal stability.
• Many VFD manufacturers specify a minimum vessel volume (e.g., 50–100 L even for small systems).
• Undersized vessels cause pressure hunting and frequent speed changes.

Step 3: Mount the Vessel Correctly

• Vertical vessels preferred for most VFD booster sets
• Vessel must be fully supported on floor or base
• Do not allow pipework to carry vessel weight
• Use anti-vibration pads if pumps are large

Step 4: Install Isolation Valve and Drain Valve

• Isolation valve allows vessel servicing without system shutdown
• Drain valve required for pre-charge checks and commissioning

Both are mandatory in professional VFD installations.

Step 5: Set Pre-Charge Pressure (Critical Step)
For VFD systems, pre-charge rules differ slightly from fixed-speed pumps:

• Pre-charge should be set 0.5–1.0 bar below the VFD set pressure

Example:

• VFD set pressure = 4.0 bar
• Vessel pre-charge = 3.0–3.5 bar

This ensures the vessel is active at low flow but does not fight the pump during normal operation.

Step 6: Commission the System

• Start VFD system and allow it to stabilize
• Observe pressure curve on controller display
• Confirm no oscillation, hunting, or rapid speed changes
• Check vessel drawdown by opening and closing small outlets

6. Using Multiple Pressure Vessels with VFD Systems
For large or high-rise systems:

• Install multiple Wates vessels in parallel
• All vessels must have identical pre-charge pressure
• Connect all vessels to the same discharge header

Benefits include:

• Better pressure stability
• Higher drawdown volume
• Redundancy during maintenance

7. Common Installation Mistakes in VFD Systems

• Installing no vessel at all
• Using very small vessels (24–50 L) on large VFD systems
• Incorrect pre-charge pressure
• Installing vessel far from pressure sensor
• Connecting vessel to one pump only
• Allowing vibration to reach vessel through rigid piping

8. Special Considerations for Multi-Pump VFD Booster Sets

• Pressure vessel stabilizes pressure when pumps switch on/off
• Prevents sudden speed jumps during pump sequencing
• Essential in high-rise buildings with fluctuating demand
• Must be sized for worst-case low-flow condition

9. UAE / GCC Installation Notes

• High ambient temperatures increase pressure sensitivity—larger vessels are recommended
• Pre-charge should be checked more frequently (every 3–6 months)
• Install vessels in shaded, ventilated pump rooms
• Use stainless-steel or corrosion-resistant fittings in coastal locations

10. Final Commissioning Checklist
Before handover, confirm:

• Vessel installed on discharge manifold
• Correct vessel size and pressure rating
• Isolation and drain valves installed
• Pre-charge set correctly for VFD operation
• No pressure hunting or oscillation
• Smooth pump speed modulation
• All values documented for maintenance

When properly installed, a Wates pressure vessel is a critical stability component in VFD pump systems.
Correct sizing, correct location, and correct pre-charge settings ensure:

• Smooth pressure control
• Energy-efficient operation
• Reduced wear on pumps and drives
• Long system service life

A VFD system without a correctly installed pressure vessel is incomplete. For more info contact Wates Pressure Vessel Supplier in UAE or call us at +971 4 2522966.

Correct commissioning and testing are the final and most critical steps after installing a Wates pressure vessel.
Even a perfectly installed vessel can fail to perform if commissioning is skipped or done incorrectly.
Proper testing ensures:

• Stable system pressure
• Correct pump operation
• Reduced cycling and energy consumption
• Long service life of the vessel and pump

2. When Commissioning Should Be Done
Commissioning must be carried out:

• After mechanical installation is complete
• Before the system is handed over to the client
• After any bladder replacement or major maintenance
• After pressure switch or VFD settings are changed

Never commission a pressure vessel while the system is partially installed or under construction.

3. Pre-Commissioning Safety Checks
Before pressurizing the system, verify the following:

• Vessel is securely mounted (no load on pipework)
• Correct orientation (vertical or horizontal as per model)
• Isolation valve, drain valve, and pressure gauge installed
• All fittings tightened and sealed correctly
• Vessel pressure rating matches system maximum pressure
• Installation area is safe, ventilated, and accessible

4. Step-by-Step Commissioning Procedure
Step 1: Isolate and Fully Drain the Vessel

• Close the isolation valve between vessel and system
• Open the drain valve to remove all water from the vessel
• Ensure zero water pressure inside the tank

This step is essential—pre-charge must never be checked with water inside the vessel.

Step 2: Check and Set Pre-Charge Pressure

• Use a reliable air pressure gauge on the Schrader valve
• Compare reading with required value

Correct rule:
Pre-charge = Pump cut-in pressure − 0.2 to 0.5 bar
Example:

• Pump cut-in: 2.5 bar
• Vessel pre-charge: 2.0–2.3 bar

Adjust using an air pump or release air as required.
Re-fit the valve cap tightly (preferably metal).

Step 3: Open Isolation Valve and Refill System

• Slowly open the isolation valve
• Allow water to enter the vessel
• Observe pressure gauge for smooth pressure rise

Check all joints and fittings for leaks.

Step 4: Start the Pump and Observe Cut-Out Pressure

• Start the pump and allow system to reach cut-out pressure
• Confirm cut-out pressure is below vessel maximum rating
• Ensure pump stops cleanly without pressure overshoot

Step 5: Test Drawdown Performance

• Open a tap or outlet downstream
• Observe pressure drop on gauge
• Confirm water flows from the vessel before pump restarts

This confirms the vessel is storing usable water volume correctly.

Step 6: Verify Pump Cycling Frequency

• Run system under normal demand conditions
• Confirm pump does not short-cycle
• Typical acceptable range: 10–20 starts per hour

Excessive cycling indicates incorrect pre-charge or undersized vessel.

5. System Stability Tests
5.1 Pressure Stability

• Pressure should drop gradually, not suddenly
• No pressure hunting or oscillation

5.2 Noise and Vibration

• No banging, knocking, or water hammer
• Vessel should remain stable without movement

5.3 Multi-Pump or VFD Systems

• Pumps should sequence smoothly
• No rapid on/off switching
• Pressure sensor readings should remain steady

6. Final Inspection Checklist
Before handover, confirm:

• Pre-charge pressure recorded
• No air or water leaks
• Isolation valve operational
• Drain valve accessible
• Pressure gauge readable and accurate
• Vessel fully supported and aligned
• System pressure within design limits

7. Common Commissioning Mistakes to Avoid

• Checking pre-charge with water inside the vessel
• Skipping drawdown test
• Ignoring pump cycling frequency
• Leaving isolation valve partially closed
• Failing to tighten Schrader valve cap
• Not documenting final pressure settings

8. Documentation and Handover
Record the following for future maintenance:

• Vessel model and capacity
• Pre-charge pressure value
• Pump cut-in and cut-out settings
• Commissioning date
• Installer or technician name

This documentation is essential for warranty and service history.

9. UAE / GCC Commissioning Notes

• High ambient temperature may slightly increase pressure after commissioning
• Re-check pre-charge after 24–48 hours of operation
• In hot pump rooms, schedule pre-charge inspection every 3–6 months
• Coastal installations require periodic inspection for corrosion

Commissioning and testing are not optional steps—they determine how well a Wates pressure vessel will perform throughout its service life.
Correct pre-charge adjustment, drawdown testing, and pump cycling verification ensure:

• Stable pressure
• Reduced energy consumption
• Longer pump and vessel lifespan
• Fewer service calls

A properly commissioned vessel is the foundation of a reliable water pressure system. For more info contact Wates Pressure Vessel Supplier in UAE or call us at +971 4 2522966.

Solar water heater systems operate under high temperature and pressure variations, making expansion vessels a critical safety and performance component.
A Wates expansion vessel absorbs thermal expansion of water, prevents pressure spikes, protects valves and piping, and ensures long-term reliability of the solar system.
This guide explains how to correctly install a Wates expansion vessel in solar water heater applications.


2. Why Expansion Vessels Are Required in Solar Water Heater Systems
When water is heated, it expands. In a closed solar system:

• Pressure rises rapidly if expansion is not controlled
• Safety relief valves may discharge frequently
• Pipes, storage tanks, and heat exchangers are exposed to stress
• System efficiency and component lifespan are reduced

A Wates expansion vessel provides a controlled air cushion to safely absorb this expansion.

3. Difference Between Pressure Vessels and Expansion Vessels in Solar Systems

• Pressure vessel: stabilizes pressure caused by water demand (used in booster systems)
• Expansion vessel: absorbs thermal expansion due to temperature rise

For solar water heaters, expansion vessels are mandatory, even if a pressure vessel exists elsewhere in the system.

4. Types of Solar Systems That Require Expansion Vessels

• Pressurized flat plate solar water heaters
• Evacuated tube solar systems
• Forced circulation solar systems
• Solar systems with storage tanks and heat exchangers
• Solar systems integrated with boilers or calorifiers

5. Key Components in a Solar Expansion Vessel Installation

• Wates expansion vessel (solar-rated)
• Safety relief valve (temperature & pressure rated)
• Pressure gauge
• Isolation valve
• Non-return valve (where required)
• Drain valve
• Solar-rated piping and fittings

6. Correct Location for Installing a Wates Expansion Vessel
6.1 On the Cold Water Side

• Install the expansion vessel on the cold water inlet line of the solar storage tank
• Must be installed after the non-return valve
• Never install on the hot water outlet

6.2 Close to the Storage Tank

• Reduces pressure fluctuation delay
• Improves expansion absorption efficiency

6.3 Indoor or Shaded Location

• Protect from direct sunlight and excessive heat
• Essential in hot climates like UAE and GCC

7. Step-by-Step Installation Procedure
Step 1: Isolate and Depressurize the System

• Shut off water supply
• Release pressure from the solar tank using relief valve

Step 2: Install the Tee Connection

• Fit a tee on the cold water inlet line of the solar tank
• Tee branch will connect the expansion vessel

Step 3: Install Isolation Valve

• Install a ball valve between tee and expansion vessel
• Allows vessel servicing without draining the entire solar system

Step 4: Mount the Wates Expansion Vessel

• Vertical mounting is preferred
• Ensure vessel is fully supported on floor or wall bracket
• Do not allow pipework to carry vessel weight

Step 5: Install Pressure Gauge and Drain Valve

• Pressure gauge helps monitor system pressure
• Drain valve allows vessel isolation and pre-charge checks

Step 6: Set Pre-Charge Pressure

• Pre-charge must match cold water supply pressure
• Typical rule:
  Pre-charge = incoming cold water pressure
• Adjust pre-charge before filling system with water

Step 7: Refill and Commission the System

• Slowly refill solar system
• Check for leaks
• Heat system and observe pressure rise
• Confirm relief valve does not discharge under normal operation

8. Sizing Considerations for Solar Expansion Vessels
Sizing depends on:

• Solar storage tank capacity
• Maximum water temperature
• Cold water inlet pressure
• System operating pressure

Typical guidelines:

• 150–200 L solar tank → 12–18 L expansion vessel
• 300 L solar tank → 18–24 L vessel
• Large commercial systems → 35 L and above (or multiple vessels)

Always size based on thermal expansion volume, not tank size alone.

9. Special Considerations for Solar Systems in UAE & GCC
9.1 High Operating Temperatures

• Solar water can exceed 80–90°C
• Use solar-rated expansion vessels only

9.2 Heat Accelerates Air Loss

• Check pre-charge every 6 months
• Use metal valve caps to reduce leakage

9.3 Rooftop Installations

• Install vessel below roof level in shaded service area
• Avoid direct sun exposure

9.4 Water Quality

• High hardness accelerates internal wear
• Periodic inspection is essential

10. Common Installation Mistakes to Avoid

• Installing expansion vessel on hot water outlet
• Using a standard pressure vessel instead of solar-rated expansion vessel
• Incorrect pre-charge pressure
• Omitting isolation valve
• Installing vessel outdoors without protection
• Undersizing expansion vessel
• Relying on safety valve instead of proper expansion control

11. Maintenance Requirements

• Check pre-charge pressure every 6–12 months
• Inspect vessel for corrosion or coating damage
• Verify safety valve operation
• Replace bladder if vessel becomes waterlogged

12. Safety and Compliance

• Ensure expansion vessel pressure rating matches system design
• Use certified vessels suitable for potable hot water
• Follow manufacturer instructions and local plumbing codes
• Ensure relief valve discharge is safely piped

Installing a Wates expansion vessel correctly is essential for the safe, efficient, and long-term operation of solar water heater systems.
Correct location, accurate pre-charge setting, and proper sizing prevent pressure problems, reduce maintenance, and protect expensive solar components. For more info contact Wates Pressure Vessel Supplier in UAE or call us at +971 4 2522966.