How to Install Roots Blower

Proper installation of a roots blower is critical for reliable operation and long service life. Based on commissioning experience across hundreds of installations, 60% of field problems trace to installation errors – improper foundation, pipe strain, misalignment, or electrical issues. A correct installation prevents bearing failure, vibration, and premature wear.

This guide provides a step-by-step procedure for installing a roots blower – from foundation preparation to pre-commissioning checks. Follow these guidelines to ensure reliable operation.

Table of Contents

• What Does a Roots Blower Installation Involve?

• Pre-Installation Planning

• Step 1: Foundation Preparation

• Step 2: Blower Placement and Leveling

• Step 3: Piping Installation

• Step 4: Coupling and Alignment

• Step 5: Electrical Connections

• Step 6: Oil and Lubrication

• Step 7: Pre-Commissioning Checks

• Step 8: Start-Up

• Common Installation Mistakes

• Frequently Asked Questions

• Final Thoughts

What Does a Roots Blower Installation Involve?

A roots blower installation includes foundation preparation, blower placement, piping connections, coupling alignment, electrical wiring, and pre-commissioning checks. Proper installation is essential for reliability and longevity.

Installation steps:

1. Foundation preparation

2. Blower placement and leveling

3. Piping installation (inlet and discharge)

4. Coupling and alignment

5. Electrical connections

6. Oil and lubrication

7. Pre-commissioning checks

8. Start-up

Based on field data, a proper installation takes 1–2 days for a packaged unit and 2–3 days for field-assembled components.

Pre-Installation Planning

Before starting installation:

1. Review documentation.

• Installation manual

• Dimensional drawings

• P&ID (piping and instrumentation diagram)

• Electrical schematics

• Foundation drawings

2. Verify equipment.

• Check model and serial number

• Inspect for shipping damage

• Verify accessories are included

• Check motor voltage and frame

3. Prepare site.

• Clean area

• Verify foundation is ready

• Check overhead clearance

• Plan lifting and rigging

4. Gather tools.

• Laser alignment tool (preferred) or dial indicators

• Torque wrench

• Level (precision)

• Wrenches and sockets

• Lifting equipment (crane, hoist, slings)

5. Review safety requirements.

• Lock-out/tag-out procedures

• Lifting safety

• Personal protective equipment (PPE)

Step 1: Foundation Preparation

Foundation requirements:

• Rigid concrete or steel base

• Minimum mass: 3× blower weight

• Level surface (within 0.002 inches per foot)

• Anchor bolts embedded or epoxied

Concrete foundation:

• Pour concrete with anchor bolts in place

• Allow curing (minimum 7 days)

• Grout under base frame (if required)

• Surface must be level and smooth

Steel foundation:

• Fabricate from structural steel

• Weld or bolt to building structure

• Must be rigid – no flexing

Foundation checklist:

• Foundation mass ≥ 3× blower weight

• Surface level within 0.002 inches/ft

• Anchor bolts in correct position

• Grout under base frame (if required)

• Foundation cured (concrete)

Step 2: Blower Placement and Leveling

Placing the blower:

1. Lift blower with appropriate rigging

2. Lower onto foundation or base frame

3. Align with anchor bolts

4. Install nuts and washers (finger tight)

Leveling:

1. Place precision level on machined surfaces

2. Check level in both directions (longitudinal and transverse)

3. Adjust using leveling bolts or shims

4. Recheck level – within 0.002 inches per foot

Tightening:

1. Tighten anchor bolts to specified torque

2. Recheck level (bolts can shift alignment)

3. Record final level readings

Placement checklist:

• Lifting equipment rated for weight

• Blower aligned with anchor bolts

• Level within 0.002 inches per foot

• Anchor bolts torqued to specification

• Final level verified

Step 3: Piping Installation

General piping rules:

• Flexible connectors within 18 inches of both inlet and discharge flanges

• Support piping independently – do not use blower casing as support

• No pipe strain on flanges

• Slope piping to drain (if applicable)

• Clean piping before connection (remove debris)

Inlet piping:

1. Install flexible connector within 18 inches of inlet flange

2. Support piping separately

3. Install inlet filter before flexible connector

4. Install inlet silencer (if applicable)

5. Check for vacuum-rated filter

Discharge piping:

1. Install flexible connector within 18 inches of discharge flange

2. Support piping separately

3. Install check valve within 3 feet of discharge

4. Install relief valve between blower and check valve

5. Install discharge silencer (if applicable)

Piping checklist:

• Flexible connectors within 18 inches

• Piping independently supported

• No pipe strain on flanges

• Inlet filter installed

• Check valve installed (discharge)

• Relief valve installed (between blower and check valve)

• Piping clean before connection

Step 4: Coupling and Alignment

Coupling installation:

1. Verify coupling halves are clean

2. Install coupling on motor shaft

3. Install coupling on blower shaft

4. Install coupling guard (safety)

Alignment requirements:

• Parallel offset: ≤0.002 inches (0.05 mm)

• Angular misalignment: ≤0.001 inches per inch

• Follow coupling manufacturer specifications

Alignment methods:

1. Laser alignment (best – fastest, most accurate)

2. Dial indicator (traditional, accurate)

3. Straight edge and feeler gauge (least accurate, not recommended)

Alignment procedure:

1. Mount laser alignment tool or dial indicators

2. Measure parallel and angular misalignment

3. Adjust motor using shims

4. Recheck alignment

5. Tighten motor bolts

6. Recheck alignment (bolts can shift)

Alignment checklist:

• Coupling clean and installed

• Parallel offset ≤0.002 inches

• Angular misalignment ≤0.001 inches/in

• Alignment rechecked after tightening

• Coupling guard installed

Step 5: Electrical Connections

Motor wiring:

1. Verify motor voltage matches supply

2. Connect power leads to motor terminals

3. Connect ground wire

4. Install conduit or cable tray

5. Verify overload protection is sized correctly

Control wiring:

1. Connect pressure switch (if applicable)

2. Connect temperature switch (if applicable)

3. Connect VFD control wiring (if applicable)

4. Connect remote start/stop (if applicable)

VFD installation (if applicable):

1. Locate VFD in clean, dry area

2. Ambient temperature below 104°F

3. Provide adequate ventilation

4. Install line reactor (reduce harmonics)

5. Install output reactor (protect motor)

6. Use shielded motor cable

7. Proper grounding

Electrical checklist:

• Voltage verified

• Connections tight

• Ground wire connected

• Overload protection sized correctly

• VFD installed correctly (if applicable)

• Control wiring connected

Step 6: Oil and Lubrication

Oil type:

• Synthetic ISO VG 150 or 220 (check manufacturer specification)

• Do not mix synthetic and mineral oil

Oil filling:

1. Remove fill plug

2. Fill with correct oil to sight glass midpoint

3. Install fill plug

Oil level:

• Check with blower level and stopped

• Oil level at middle of sight glass

Oil checklist:

• Correct oil type used

• Oil level at sight glass midpoint

• No overfilling

Step 7: Pre-Commissioning Checks

Before start-up:

Mechanical checks:

• All bolts tight (foundation, motor, blower)

• Coupling guard installed

• Piping supported

• No pipe strain

• Belt tension (if belt drive)

• Rotation direction verified (manual check)

Electrical checks:

• Voltage verified

• Wiring correct

• Ground connected

• Overload protection set correctly

• Motor rotation direction checked (jog motor)

System checks:

• Inlet filter installed

• Check valve installed (discharge)

• Relief valve installed and set

• Pressure gauge installed

• Temperature gauge installed

• All valves open

Safety checks:

• Lock-out/tag-out removed

• Guards in place

• Area clear of personnel

• Fire extinguisher available

Step 8: Start-Up

Start-up procedure:

1. Jog motor. Briefly start motor to verify rotation direction. Correct by swapping two motor leads if needed.

2. Run unloaded. Run blower for 5–10 minutes with no load (relief valve open or discharge open). Check for unusual noise or vibration.

3. Check oil level. Stop blower, check oil level. Add oil if needed.

4. Load blower. Gradually close discharge valve or allow system to pressurize. Monitor pressure and temperature.

5. Check alignment. After first hour of operation, check coupling alignment. Thermal expansion can change alignment.

6. Record baseline readings. Pressure, temperature, vibration, motor amps. Record for future reference.

Start-up checklist:

• Rotation direction verified

• No unusual noise or vibration

• Oil level checked and corrected

• Pressure within design range

• Temperature below 220°F

• Alignment rechecked after warm-up

• Baseline readings recorded

Common Installation Mistakes

1. No flexible connectors.
Hard piping causes pipe strain and misalignment. Always use flexible connectors within 18 inches.

2. Piping not supported.
Pipe weight on blower casing causes distortion and misalignment. Support piping independently.

3. Poor alignment.
Misalignment causes bearing failure and vibration. Align to ≤0.002 inches parallel.

4. No check valve.
Backspin damages timing gears. Install check valve on discharge.

5. No relief valve.
Overpressure damages blower. Install relief valve between blower and check valve.

6. Wrong oil.
Incorrect oil causes bearing failure. Use specified oil.

7. Overfilling oil.
Overfilling causes foaming and overheating. Fill to sight glass midpoint.

8. No rotation direction check.
Wrong rotation damages timing gears. Check rotation before loading.

Frequently Asked Questions

1. How long does roots blower installation take?
Packaged unit: 1–2 days. Field-assembled components: 2–3 days. Includes foundation, piping, alignment, electrical, and pre-commissioning. Larger blowers or complex systems may take longer.

2. What foundation is required?
Rigid concrete or steel base. Minimum mass: 3× blower weight. Surface level within 0.002 inches per foot. Anchor bolts embedded or epoxied.

3. What alignment is required?
Parallel offset ≤0.002 inches (0.05 mm). Angular misalignment ≤0.001 inches per inch. Laser alignment is preferred – faster and more accurate.

4. What oil should I use?
Synthetic ISO VG 150 or 220. Check manufacturer specification. Do not mix synthetic and mineral oil.

5. Why are flexible connectors required?
Flexible connectors prevent pipe strain on blower flanges. Thermal expansion and vibration are isolated from the blower. Install within 18 inches of both inlet and discharge flanges.

6. Where should the check valve be installed?
On discharge piping, within 3 feet of blower flange. Prevents backspin when blower stops – backspin damages timing gears.

7. Where should the relief valve be installed?
Between blower and check valve. Set at operating pressure + 2 psig. Protects against overpressure.

8. Why is alignment important?
Misalignment causes bearing failure and vibration. Proper alignment extends bearing life by 2–3×.

9. How do I check rotation direction?
Jog the motor briefly. Check rotation arrow on blower casing. Swap any two motor leads if rotation is wrong.

10. What baseline readings should I record?
Discharge pressure, discharge temperature, motor amps, vibration (overall), oil level. Record after start-up for future reference.

11. Can I install a roots blower outdoors?
Yes – with weather protection. Install shelter or cover. Provide cooling air – avoid recirculating hot air.

12. What is the recommended piping material?
Carbon steel for standard applications. Stainless steel for corrosive gas. Schedule 40 minimum. Use flexible connectors.

13. How do I check for pipe strain?
Check flanges for gap or misalignment. Piping should not force blower out of alignment. Use dial indicator on flanges.

14. What is the minimum clearance around the blower?
36 inches on all sides for maintenance access. 60 inches above for lifting.

15. Do I need a VFD?
VFD is recommended for variable flow applications. Saves energy 25–35%. Specify inverter-duty motor with VFD.

Final Thoughts

After commissioning hundreds of roots blower installations, here is my practical advice:

Foundation is critical. A rigid foundation prevents misalignment and vibration. Mass at least 3× blower weight. Level within 0.002 inches per foot.

Piping must be supported independently. Pipe weight on the blower causes distortion and misalignment. Use flexible connectors within 18 inches of both flanges.

Alignment matters. Misalignment is the leading cause of bearing failure. Align to ≤0.002 inches parallel. Laser alignment is fastest and most accurate.

Check rotation direction before loading. Wrong rotation damages timing gears. Jog the motor and check the arrow.

Record baseline readings. Pressure, temperature, vibration, motor amps. Baseline data helps troubleshoot future problems.

The bottom line. Proper installation is the foundation of reliable roots blower operation. Zhanggu and other manufacturers provide installation manuals. Follow the steps. Take the time to do it right. A correct installation prevents 60% of field problems.