Little GIANT MDP-1 Submersible Main Drain Pump Owner’s Manual

Little GIANT MDP-1 Submersible Main Drain Pump

Product Information

The MDP-1 Submersible Main Drain Pump is a manually operated, portable submersible pump designed for draining chlorinated or salt water from in- ground swimming pools during maintenance and liner replacement. It features an inlet screen that fits inside the drain to pump out most of the remaining drain water. This pump series is available only as a manual model but can be converted to operate automatically by installing a separate liquid level control. The pump motor is equipped with an automatic resetting thermal protector and may restart unexpectedly if the thermal protector trips due to motor overloading or overheating. The product comes with a Limited Warranty of 1 year from the date of original purchase by the consumer.

Specifications

• Voltage: 115V
• HP: 3/4
• Flow Rate: 850 Gallons (Liters) per Hour
• Hz: 60
• Full Load Amps: 8.5
• Watts: 850
• Cord Length: 25 ft (7.6 m)
• Shut Off Max: 43.5 ft (13.3 m)
• Max PSI (Bar): 18.9 (1.3)

Safety Instructions
Risk of bodily injury, electric shock, or equipment damage. Follow the safety instructions provided in the user manual.

Installation

Physical Installation
Follow the physical installation instructions provided in the user manual.

Electrical Connections
Follow the electrical connection instructions provided in the user manual.

Operation
Testing

1. Plug the power cord directly into an electrical outlet or switch on power at the junction box.
2. Confirm that the pump is functioning as intended.
3. Unplug the unit as soon as the pump stops pumping water or the suction sound changes.

Maintenance

Periodic Service
Risk of severe injury or death by electrical shock, high temperatures, or pressurized fluids. Follow the maintenance instructions provided in the user manual.

1. Disconnect the pump from electric power.
2. Disconnect the discharge hose from the pump.
3. Unscrew the four clamp screws and remove the screen.
4. Remove the screws that hold the volute to the motor housing.
5. Remove the volute, being careful not to lose the seal ring.
6. Clean the impeller and the volute passage. Note: Do not use strong solvents on the impeller.
7. Ensure the impeller turns freely after cleaning.
8. Replace the seal ring into the volute and secure the volute to the motor housing with screws.
9. Replace the screen onto the volute.

Troubleshooting

equipped with GFCI.
Turn on circuit breaker or replace fuse.
Pump runs but does not discharge liquid| Lift too high for pump
Starting depth of water too shallow
Inlet to impeller plugged| Check rated pump performance.
Add water to pool.
Pull pump and clean.
Pump does not deliver| Low voltage, speed too slow| Check rated pump performance.

MDP-1 Submersible Main Drain Pump

This manually operated, portable submersible pump is designed for draining chlorinated or salt water from in-ground swimming pools during maintenance and liner replacement. The inlet screen is designed to fit inside the drain and pump out most of the remaining drain water.
This pump series is available only as a manual model. The manual pump can be converted to operate automatically by installing a separate liquid level control. The pump motor is equipped with an automatic resetting thermal protector and may restart unexpectedly. Thermal Protector tripping indicates motor overloading or overheating.

This product is covered by a Limited Warranty for a period of 1 year from the
date of original purchase by the consumer. For complete warranty information, refer to www.LittleGiant.com.

Specifications

Voltage| HP| Hz| Full Load Amps| Watts| Cord Length ft (m)
---|---|---|---|---|---
115| 3/4| 60| 8.5| 850| 25 (7.6)

Flow Rate

Gallons (Liters) per Hour at Height| ****

Shut Off ft (m)

| ****

Max PSI (Bar)

---|---|---
0 ft

(0.0 m)

| 5 ft

(1.5 m)

| 10 ft

(3.0 m)

| 15 ft

(4.6 m)

| 20 ft

(6.1 m)

| 30 ft

(9.1 m)

| 40 ft

(12.2 m)

4260

(16,124)

| 4020

(15,215)

| 3670

(13,890)

| 3290

(12,454)

| 2890

(10,940)

| 1880

(7116)

| 580

(2196)

| 43.5

(13.3)

| 18.9

(1.3)

SAFETY INSTRUCTIONS
This equipment should be installed and serviced by technically qualified personnel who are familiar with the correct selection and use of appropriate tools, equipment, and procedures. Failure to comply with national and local electrical and plumbing codes and within Little Giant recommendations may result in electrical shock or fire hazard, unsatisfactory performance, or equipment failure.
Know the product’s application, limitations, and potential hazards. Read and follow instructions carefully to avoid injury and property damage. Do not disassemble or repair unit unless described in this manual.
Refer to product data plate(s) for additional precautions, operating instructions and specifications.
Failure to follow installation or operation procedures and all applicable codes may result in the following hazards:

DANGER: Risk of death, personal injury, or property damage due to explosion, fire, or electric shock.

• Do not use to pump flammable, combustible, or explosive fluids such as gasoline, fuel oil, kerosene, etc.
• Do not use in explosive atmospheres or hazardous locations as classified by the NEC, ANSI/NFPA70.
• Do not handle a pump or pump motor with wet hands or when standing on a wet or damp surface, or in water.
• When a pump is in its application, do not touch the motor, pipes, or water until the unit is unplugged or electrically disconnected.
• If the power disconnect is out of sight, lock it in the open position and tag it to prevent unexpected application of power.

WARNING: High voltages capable of causing severe injury or death by electrical shock are present in this unit.

• To reduce risk of electrical shock, disconnect power before working on or around the system. More than one dis-connect switch may be required to de-energize the equipment before servicing.
• Be certain that this pump is connected to a circuit equipped with a ground fault circuit interrupter (GFCI) device if required by code.
• This pump is supplied with a grounding conductor and grounding-type attachment plug. To reduce risk of electric shock, be certain that it is connected only to a properly grounded grounding-type receptacle. Do not remove the third prong from the plug.
• Be sure the electrical connection cannot be reached by rising water.
• Check electrical outlets with a circuit analyzer to ensure power, neutral, and ground wires are properly connected. If not, a qualified, licensed electrician should correct the problem.
• Wire pump system for correct voltages.
• Do not use the power cord for lifting the pump.
• Do not use an extension cord.

CAUTION: Risk of bodily injury, electric shock, or equipment damage.

• This equipment must not be used by children or persons with reduced physical, sensory, or mental abilities, or lacking in experience and expertise, unless supervised or instructed. Children may not use the equipment, nor may they play with the unit or in the immediate vicinity.
• Equipment can start automatically. Always unplug the pump power cord and disconnect the electrical power before servicing the pump or switch.
• Do not run the pump dry. If run dry, the surface temperature of the pump will rise to a high temperature that could cause skin burns if touched, and will cause serious damage to the pump.
• Do not oil the motor. This unit is permanently lubricated. Oiling is not required. The pump’s motor housing is sealed. Do not open the sealed portion of the unit or remove housing screws. Opening the motor housing could cause serious electric shock and/or permanent damage to the pump.
• This pump has been evaluated for use with water only. Pump should only be used with liquids compatible with pump component materials. If the pump is used with liquids incompatible with the pump components, the liquid can cause failure to the electrical insulation system resulting in electrical shock.
• Operation of this equipment requires detailed installation and operation instructions provided in this manual for use with this product. Read entire manual before starting installation and operation. End User should receive and retain manual for future use.
• Keep safety labels clean and in good condition.
• If an accessory float switch or other liquid level control is installed, refer to manufacturer’s instructions. Failure to install control in compliance with national and local electrical and plumbing codes and within manufacturer’s recommendations may result in electrical shock or fire hazard, unsatisfactory performance, or equipment failure.
• Pumping sand or other abrasives can damage the pump and void the warranty.

NOTICE: Risk of damage to pump or other equipment.

• Do not run pump dry. For optimal cooling and to prolong the motor life, the liquid level being pumped should nor-mally be above the top of the pump housing.
• This pump is not suitable for pond applications.
• Warranty is void if the motor housing cover or power cord have been removed.

PRODUCT INSTALLATION

Physical Installation

IMPORTANT: Do not plug in the pump until all plumbing connections are complete and pump is secure.

1. Connect discharge plumbing using the 1-1/4 inch (3.18 cm) FNPT pipe thread, 1-1/2 inch (3.81 cm) barbed adapter, or the 3/4 inch (1.91 cm) garden hose adapter.
   • If using the 3/4 inch (1.91 cm) garden hose adapter, performance will be reduced by approximately 15%.
   • If flexible vinyl tubing is used, a clamp can be used on the tubing to restrict the flow.
2. Place the pump base in the main drain.
   • The water should be at least 3 inches (7.62 cm) deep.
   • The pump should only operate when water is present. Once the pump empties the drain, unplug the pump.
   • Never place the pump directly on clay, earth, or gravel surfaces.
3. Securely position the free end of the hose or pipe where the water is to be relocated.

Electrical Connections
Connect the power cord to a constant source of power matching the pump nameplate voltage.

• Connect the pump to its own circuit, with no other electric receptacles or equipment in the circuit.
• Ensure that the fuses or circuit breaker are of ample capacity in the electrical circuit.
• Pumps are to be plugged into a dedicated GFCI receptacle and are powered on/off by plugging in and unplugging the pump power cord. The pumps can be converted to automatic operation by installing a separate liquid level control, according to the manufacturer’s instructions.

OPERATION

TESTING

NOTICE: Risk of damage to pump or other equipment.

• Always check the power cord and electric receptacle for damage or corrosion before each use. The power cord on these units cannot be replaced. If damaged, replace the pump.
• Do not let the unit run dry (without liquid). It is designed to be cooled by pumping fluid. The seal may be dam-aged and the motor may fail if the pump is allowed to run dry.
• Do not let the unit freeze. Freezing may cause cracking or distortion that may destroy the unit.

1. Plug the power cord directly into an electrical outlet or switch on power at the junction box.
2. Confirm that the pump is functioning as intended.
3. Unplug the unit as soon as the pump stops pumping water or the suction sound changes.
   • If the unit is going to be idle for a period of time, follow the cleaning instructions in “Periodic Service” on page 5.

PRODUCT MAINTENANCE

Periodic Service

WARNING: Risk of severe injury or death by electrical shock, high temperatures, or pressurized fluids.

• Always unplug the pump power cord in addition to removing the fuse or shutting off the circuit breaker before working on the pump or switch.
• Let pump cool for a minimum of 2 hours before attempting to service. Submersible pumps can become pressur-ized and hot under normal operating conditions.

NOTICE: Risk of damage to pump or other equipment.

• Do not remove the motor housing cover.
• Do not remove the impeller. This action requires special tools and may damage the pump.

Rinse and flush the pump with clean water completely after each use in salt water and any type of acid wash.

1. Disconnect the pump from electric power.

2. Disconnect the discharge hose from the pump.

3. Unscrew the four clamp screws and remove the screen.

4. Remove the screws that hold the volute to the motor housing.

5. Remove the volute, being careful not to lose the seal ring.

6. Clean the impeller and the volute passage.
   NOTE: Do not use strong solvents on the impeller.

7. Be sure the impeller turns freely after cleaning.

8. Replace the seal ring into the volute and secure the volute to the motor housing with screws.

9. Replace the screen onto the volute.

Troubleshooting

Pump does not turn on

| Pump not connected to electrical power| Connect pump to a dedicated circuit

equipped with GFCI.

Circuit breaker off or fuse removed| Turn on circuit breaker or replace fuse.
Defective motor| Replace pump.
Pump runs but does not discharge liquid| Lift too high for pump| Check rated pump performance.
Starting depth of water too shallow| Add water to pool.
Inlet to impeller plugged| Pull pump and clean.

Pump does not deliver rated capacity

| Lift too high for pump| Check rated pump performance.
Low voltage, speed too slow| Check that supply voltage matches the

nameplate rating.

Impeller or discharge pipe is clogged| Pull pump and clean. Check pipe for

scale or corrosion.

Impeller wear due to abrasives| Replace pump.

For technical assistance, parts, or repair, please contact:
800.701.7894 | littlegiant.com
10000011581 Rév. 004 08/22

Franklin Electric Co., Inc. | Oklahoma City, OK 73157-2010 Copyright © 2022, Franklin Electric, Co., Inc. All rights reserved.

References

• HVAC and Wastewater Pumps & Systems | Little Giant
• HVAC and Wastewater Pumps & Systems | Little Giant

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