XBD-CDS Horizontal Split-Case Fire Pump — Start-Up, Troubleshooting & Specifications
The XBD-CDS horizontal split-case double-suction fire pump draws on the proven CDOW pump platform for reliable fire protection water supply across industrial and commercial installations. Its split-case design allows maintenance technicians to access the impeller and shaft assembly without disturbing the suction or discharge piping, which significantly reduces service downtime during routine inspections.
Design Features
The pump body and cover are cast using resin sand molding, which ensures precise geometry and smooth internal flow passages — this improves hydraulic efficiency and reduces energy consumption across the operating range. The shortened bearing span increases shaft rigidity, keeping vibration and noise within acceptable limits even at full rated speed. The mechanical seal construction eliminates drip leakage during normal operation.
Core Performance Parameters
| Parameter | Value |
| Flow rate | 60 – 350 L/s |
| Head | 30 – 200 m |
| Motor power | 30 – 1000 kW |
| Rated speed | 1450 or 2900 r/min |
| Voltage options | 380 V, 6 kV, 10 kV |
| Max bearing temperature | 75 C |
| Lubricant | Calcium-based grease, 1/3 to 1/2 of bearing housing volume |
Start-Up and Shutdown Procedure
Pre-Start Checks
- Manual rotation test — Rotate the pump shaft by hand. It should turn smoothly without binding or excessive resistance. Any roughness indicates potential bearing damage or seal interference that must be addressed before energizing the motor.
- Priming — Close the discharge gate valve and fill the pump casing with water. If no foot valve is installed, use a vacuum pump to draw water into the casing. Confirm the pump is completely filled with no air pockets trapped in the volute.
- Gauge isolation — If vacuum or pressure gauges are mounted on the pump, close the isolation cocks connecting them to the pump before starting the motor. This protects the gauges from pressure surge during startup.
Startup Sequence
- Start the motor with the discharge gate valve closed.
- Wait for the motor to reach rated speed — the pressure gauge should show stable reading.
- Open the gauge isolation cocks and verify the pressure reading is within the expected range.
- Gradually open the discharge gate valve. If the flow rate is too high, close the valve slightly to reduce it. If the flow is too low, open the valve further.
Shutdown Procedure
- Close the vacuum and pressure gauge isolation cocks.
- Close the discharge gate valve.
- Cut power to the motor.
- In cold environments, remove the square-head drain plug from the bottom of the pump body and drain residual water to prevent freeze damage.
Troubleshooting Guide
Pump does not prime — pressure and vacuum gauge needles swing violently
Causes: Insufficient water in the casing, or air leakage in the suction piping or instrument connections. Fix: Add more water to the casing, then tighten or seal any leaking joints.
Pump does not prime — vacuum gauge reads high vacuum
Causes: Foot valve not fully open or clogged, excessive suction line resistance, or suction lift too high. Fix: Clean or replace the foot valve, flush the suction piping, or reduce the suction lift height.
No water delivery — pressure gauge shows pressure
Causes: Excessive discharge line resistance, motor rotation direction reversed, impeller clogged, or speed below rated value. Fix: Check and shorten discharge piping if possible, verify and correct motor rotation, clean the impeller, and verify supply voltage meets specifications.
Low flow or insufficient head
Causes: Impeller or piping blockage, excessive wear on the double-suction seal ring, damaged impeller, or speed below rated value. Fix: Clean the impeller and piping, replace worn components, and adjust speed to the rated setting.
Excessive power consumption
Causes: Gland packing too tight, impeller rubbing against the seal ring, or flow rate exceeding design point. Fix: Loosen the packing gland, investigate and eliminate mechanical friction, and reduce valve opening to lower flow.
Abnormal noise and no water delivery
Causes: High suction resistance, excessive suction lift, air ingress at the suction point, liquid temperature too high, or cavitation from excessive flow. Fix: Clean the suction line foot valve, lower suction lift, seal air leaks, reduce liquid temperature, or throttle the discharge valve to operate within the rated performance envelope.
Excessive vibration
Causes: Cavitation, impeller imbalance, pump and motor shaft misalignment, or loose anchor bolts. Fix: Operate within rated range, statically balance the impeller, realign pump and motor shafts, and retighten anchor bolts.
Bearing overheating
Causes: No lubricant in the bearing housing, or shaft misalignment. Fix: Clean the bearing housing and add lubricant, then realign the pump and motor shafts to the same centerline.
Application Scenarios
Industrial Fire Protection Systems
Factories, chemical plants, and storage facilities require high-flow fire water delivery. The double-suction design provides balanced axial thrust, which extends bearing life during continuous operation in fire pump service where duty cycles can run for hours.
Commercial Building Sprinkler Systems
Shopping centers, hospitals, office towers, and hotels rely on the XBD-CDS to supply both fire hydrant networks and automatic sprinkler systems. The split-case cover allows facility maintenance teams to inspect the impeller and seals during scheduled shutdowns without pulling the suction or discharge pipes.
Fire Pipe Network Booster
When municipal fire water pressure is insufficient to reach upper floors or remote fire zones, the XBD-CDS serves as a dedicated booster in the fire protection piping network, maintaining the design pressure at the most hydraulically remote sprinkler or hydrant.
Model Designation
| Code | Meaning |
| XBD | Electric Motor-Driven Fire Pump |
| CDS | Chaodun Horizontal Split-Case Double-Suction Pump |
| Rating digit (e.g., 10) | Rated pressure in MPa multiplied by 10 |
| Flow digit (e.g., 80) | Flow rate in L/s |
| G | Fire Water Supply Type |
Maintenance Schedule
- Daily — Check bearing temperature (must not exceed 75 C), listen for abnormal noise, verify gauge readings are stable.
- Monthly — Inspect elastic coupling components, check motor bearing temperature rise, verify anchor bolt tightness.
- Quarterly — Verify grease level in bearing housing (should fill 1/3 to 1/2 of the bearing space), inspect mechanical seal for any signs of leakage.
- Annually — Perform full impeller inspection through the split-case cover, check shaft alignment between pump and motor, verify impeller static balance.
Why Choose Chaodun Pumps
Chaodun Pumps manufactures the XBD-CDS horizontal split-case fire pump in compliance with relevant domestic design and testing standards. The CDOW platform pump body uses resin sand casting for dimensional accuracy, and the shortened bearing span design delivers stable operation with low vibration. Each unit undergoes factory testing before shipment to verify performance against rated flow and head parameters.
For complete dimensional drawings, installation foundation templates, and performance curves, please contact our engineering team.