Danfoss APP Pump Instruction Manual

1. Identification

This section details the identification of the pump unit. A typical pump (e.g., APP 78) is shown with its type, code number, serial number, and manufacturing origin (MADE IN DENMARK).

Diagram Description: An illustration of the APP pump unit, labeled with "PUMP", "Type: APP 78", "Code no: 180BXXXX", "Serial no: XXXXXX08-XXX", and "MADE IN DENMARK".

2. System Design

Proper system design is crucial for the APP pump's performance and longevity. Key considerations include ensuring the pump does not self-empty during standstill and that inlet pressure never exceeds outlet pressure.

A low-pressure relief valve on the inlet line is required to protect the pump from high-pressure peaks during momentary stops.

Note: Ensure the inlet connection is properly tightened to prevent air ingress, which can cause cavitation.

2.1 Open-ended systems with direct water supply

Axial piston pumps require a minimum inlet pressure as specified in the pump data sheet. The feed pressure must not exceed 5 barg (72.5 psig).

2.2 Preferred RO system design without ERD

1. Dimension the inlet line for minimal pressure loss, using large flow capacity, short pipe lengths, and few bends/connections.
2. Install an inlet filter (labeled '1' in diagrams) before the APP pump (labeled '2'). Consult Danfoss filter data sheets for selection. Thoroughly clean pipes and flush the system before startup.
3. Install a monitoring pressure switch (labeled '3') set at the minimum inlet pressure between the filter and pump inlet. This switch should stop the pump if pressure drops below the minimum.
4. Use flexible hoses (labeled '4') to reduce vibration and noise.
5. Maintain a positive pressure at the inlet (labeled '5') at all times, at least at the minimum and maximum specified inlet pressures, to prevent damage and cavitation.

It is recommended to install a safety valve or pressure relief valve (labeled '9') to prevent high-pressure peaks during momentary stops or backward spinning.

A bypass non-return valve (labeled '6') is integrated into the APP pump for system bleeding and flushing.

An outlet non-return valve (labeled '7') can be installed to prevent pump backspin. The water volume in a membrane vessel acts as an accumulator, pushing water backward if the pump stops.

A safety valve or pressure relief valve (labeled '8') can prevent system damage, as the Danfoss APP pump generates pressure and flow immediately upon startup, regardless of counter pressure.

Note: If an inlet non-return valve is used, a low-pressure relief valve is also required between the non-return valve and the pump to protect against high-pressure peaks.

Diagram Description: A schematic of a Reverse Osmosis (RO) system. It includes a media filter, the APP pump (labeled '2'), pressure sensors (PI), a pressure/temperature sensor (PT), a motor (M), and various valves and connections for feed water, permeate flush, brine, and permeate. Components like filters, pressure switches, and relief valves are indicated by numbers.

2.3 Preferred RO system design with ERD

For system diagrams (P&ID) involving an iSave, refer to the iSave® Data sheet 521B1378.

2.4 Preferred RO system design with pumps and ERDs in parallel

For systems with Danfoss pumps and ERDs operating in parallel, consult publication 180R9354, "Guideline for Parallel-coupled pumps and ERD."

2.5 Reversible pumps

If the pump experiences high outlet pressure while the motor is not energized, it may spin backward. This is not harmful as long as the inlet pressure does not exceed the maximum peak pressure of 10 barg (145 psig).

A low-pressure relief valve is required if an inlet non-return valve is installed, to protect against high-pressure pulses and general high pressure.

Alternatively, a high-pressure check valve can be fitted in the pump discharge line to prevent reversal.

An "open-end system" setup ensures inlet pressure does not exceed 10 barg (145 psig) when an inlet non-return valve is fitted.

2.6 General comments

Effective filtration is essential for a long and trouble-free pump life. The APP pumps feature very narrow internal clearances to manage leakage rates and enhance performance, making proper inlet water filtration critical to minimize wear.

The main filter should have a filtration efficiency of 99.98% at 10 µm. Precision depth filter cartridges rated 10 µm abs. β10 ≥ 5000 are recommended. Bag filters and string-wounded filters typically offer only 50% efficiency, allowing significantly more particles to pass through.

For detailed information on filtration, refer to data sheet 521B1009, "Filtration," which explains filtration definitions and provides selection guidance.

Monitoring: Continuous monitoring of the following conditions is recommended:

• Filter clogging
• Pressure (inlet and outlet sides of the pump)

Diagram Description: A diagram illustrating the alignment of a motor and pump shaft. It shows two possible misalignment scenarios: one with excessive angular and parallel offset, and another with correct alignment where the shafts are concentric. Measurements and tolerances are indicated.

3. Building up the pump unit with BoWex coupling

3.1 Assembly of the coupling

Inspect bores, shafts, keyways, and feather keys for dimensional accuracy before assembly.

Heating the hubs lightly (approx. 80°C) facilitates easier mounting onto the shaft.

[Warning] Ignition risk in potentially explosive atmospheres! Setscrews and screw connections must be secured against working loose (e.g., with Loctite). Please observe adhesive manufacturer instructions; do not apply glue on rubber surfaces.

[Warning] Touching heated hubs can cause burns. Please wear safety gloves.

Ensure the spline of the hub is fully covered by the internal spline of the elastomer. Disregarding this may damage the coupling.

3.2 Alignment between the motor and pump shaft

When assembling, ensure the hub spline is fully engaged with the elastomer's internal spline. Observe specified mounting dimensions (Lcoupling). Failure to do so can damage the coupling.

Diagram Description: A diagram illustrating the assembly of a BoWex coupling. It shows the coupling flange (component 4) being attached to the elastomer part (component 1) and then mounted onto the pump shaft. Torque specifications for bolts and nuts are provided, along with thread sizes (M5, M6, M8, M10) and corresponding torque values. A table lists components like the elastomer part, hub, and coupling flange.

3.3 Overall assembly with coupling BoWex-ELASTIC®, type HEW compact

Danfoss recommends using a Bowex Elastic HEW Compact Coupling. Refer to the Coupling Manual from BoWex for details.

Diagram Description: An exploded view of the pump unit assembly with a BoWex coupling. It shows the motor, bell housing, pump, and coupling components. Torque specifications for bolts and nuts are provided in a table with thread sizes (M5, M6, M8, M10) and torque values. A component list includes the elastomer part, hub, coupling flange, cap screws, and setscrews.

3.3.1 Mounting

1. Mount the coupling flange (component 4) to the elastomer part (component 1) and secure with a tightening torque of 120 Nm. Lubricate inside the coupling hubs, not the shafts.
2. Mount the bell housing onto the pump and secure the nuts with the specified torque.
3. Push the coupling part fully onto the pump shaft shoulder and secure with the correct torque on the locking screws.
4. Measure distance "a" from the end of the bell housing to the end of the coupling toothing.
5. Mount the coupling onto the motor shaft without using a hammer. Polish the motor shaft/key and the inside of the coupling hub if necessary.
6. Position the coupling on the motor shaft such that the length from the end of the coupling to the end of the motor flange is "b = a + 32.5 mm" ± 2 mm.
7. Secure the coupling on the motor shaft using the correct torques on the locking screws.
8. Connect the pump/bell housing to the motor carefully. Turn the motor shaft to ensure the coupling teeth engage properly.
9. Mount the motor flange bolts to the bell housing and tighten them with the correct torque.
10. Check the coupling space; the pump coupling should have 3-7 mm of space.

For alternative mounting methods, contact Danfoss High Pressure Pumps.

Ensure proper tolerances are maintained for easy coupling assembly without tools. Be mindful of recommended length tolerances, as axial force on the pump can cause damage.

Diagram Description: A detailed view showing the mounting of the coupling onto the pump shaft and motor shaft. It illustrates the measurement of distance 'a' from the bell housing to the coupling, and distance 'b' on the motor shaft, with the relationship b = a + 32.5 mm ± 2 mm. It also shows the final assembly and the required 3-7 mm coupling space.

3.4 Direction of rotation

The direction of rotation is indicated by an arrow engraved on the pump flange.

3.5 Orientation

The APP 53-92 pumps can be mounted or oriented in 45-degree increments. Refer to Data sheet 521B1340 for details.

3.6 Protection from too high pressures

The pump must be protected against excessive pressure using a safety valve or a pressure relief valve. The valve's opening characteristics should not result in peak pressures exceeding 100 barg (1450 psig).

The valve should be installed as close to the pump as possible.

Using flexible soft hoses for both the inlet and outlet lines is recommended.

The valve outlet must be connected directly to a drain, not back to the pump suction line.

Diagram Description: Two diagrams illustrating pressure relief connections. The first shows an outlet connection with a pressure relief valve leading to a drain. The second diagram shows an inlet connection with a cross-out symbol, indicating it should not be connected to the pump suction line.

4. Building up the pump unit with jaw coupling

IMPORTANT: When using a jaw coupling, it is critical to adhere to the recommended measurements.

Diagram Description: A diagram illustrating the mounting of a jaw coupling. It shows the pump shaft, motor shaft, bell housing, and coupling components. Key measurements A, B, and C are indicated, along with the required air gap between coupling parts (3-5 mm or 0.12-0.20 inch) and the offset tolerance (max 0.25 mm or 0.01 inch). Labels identify coupling parts: A (Elastic coupling), B (Bell housing), C (Motor shaft), D (Pump flange).

4.1 Mounting

1. Mount the coupling flush with the pump shaft end, or with a maximum offset of 1 mm from the pump shaft end. Ensure an air gap of 3-5 mm (0.12-0.2 inch) between coupling parts.
2. Mount the bell housing onto the pump and secure the nuts with the correct torque.
3. Measure the longest distance "A" from the top of the bell housing to the bottom of the coupling claw.
4. Mount the coupling onto the motor shaft, ensuring it does not contact the motor flange.
5. Measure distance "B" from the motor flange to the top of the coupling. This measurement "B" should be 3-5 mm (0.12-0.2 inch) shorter than measurement "A". (Measurements "A" and "B" are detailed in the accompanying diagram).
6. Adjust and verify measurements, then secure both couplings using the specified torques on the locking screws (refer to coupling operation and mounting instructions).
7. Mount the elastic gear ring and then the bell housing/pump onto the motor. After mounting, the elastic gear ring should be movable axially by 3-5 mm ("C"). This can be checked through the bell housing inspection hole. Secure the flange bolts with the correct torque.

For alternative mounting configurations, please contact Danfoss High Pressure Pumps.

Ensure proper tolerances are used for easy coupling assembly without tools. Adhere to recommended length tolerances, as axial force on the pump can cause damage.

Diagram Description: A diagram showing the torque specifications for bolts and nuts used in coupling assembly, with thread sizes M5, M6, M8, M10 and corresponding torque values. It also illustrates the axial check "C" for the elastic gear ring.

4.2 Connections

To prevent stray current corrosion, grounding of the pump and all other system parts is recommended. All system components must be electrically potential-equalized to a single reference point (grounding point).

The electrical resistance in the grounding cable should be 0.25 Ohm or less towards the grounding point.

Diagram Description: A diagram illustrating the pump's connections. It shows inlet (IN) and outlet (OUT) ports, a grounding connection point, and bleed points. It also indicates the location of a thermal sensor.

5. Initial start-up

1. Flush the inlet line before connecting the pump to remove any impurities from pipes and hoses.
2. Connect the pump inlet to the inlet line. Flush the pump for 5 minutes using the internal flushing valve to remove any remaining impurities.
3. Loosen the top bleeding plug (refer to item 3.5) using an Allen key (only plugs with internal hexagon sockets). Retighten the plug once water appears from the bleeding port.
4. Verify that the electric motor's direction of rotation matches the direction indicated on the pump flange.
5. The pump is now ready for startup.

WARNING: Ensure the electric motor's direction of rotation corresponds to the pump's direction of rotation. Incorrect rotation can damage the pump, especially if a check valve is installed between the pump and the feed pump.

Diagram Description: A diagram showing the pump with its inlet and outlet ports, and highlighting the location of the internal flushing valve. It also indicates the direction of rotation (O for clockwise, I for counter-clockwise).

6. Operation

6.1 Temperature

Fluid temperature: Minimum +2°C to maximum +50°C (Min. +35.6°F to max. +122°F).

Ambient temperature: Minimum +2°C to maximum +50°C (Min. +35.6°F to max. +122°F).

For operation at lower temperatures, contact Danfoss High Pressure Pumps.

The chart below illustrates the corrosive resistance of different stainless steel types relative to NaCl concentration and temperature. The APP water pump is constructed from Duplex and Super Duplex materials.

If the pump operates above the Super Duplex line on the chart, flush it with fresh water at the end of operation to minimize the risk of crevice corrosion.

Diagram Description: A chart titled "NaCl vs. temperature". The X-axis represents NaCl concentration in ppm (ranging from 100 to 160,000), and the Y-axis represents temperature in °C (ranging from 20 to 80). Three lines indicate the corrosive resistance limits for stainless steel grades 316L, Duplex, and Super Duplex.

6.2 Pressure

• Inlet pressure: Minimum 2 barg (30 psig), maximum 5 barg (72.5 psig). Operation at lower pressures can lead to cavitation and pump damage.
• Maximum inlet pressure peak (e.g., during momentary stops) up to 10 barg (145 psig) is acceptable.
• Maximum continuous outlet pressure: 80 barg (1160 psig).
• For APP 86: Minimum inlet pressure is 2.5 barg (36 psig), and maximum outlet pressure is 70 barg (1015 psig).
• For APP 92: Minimum inlet pressure is 3.5 barg (50 psig), and maximum outlet pressure is 70 barg (1015 psig).

Note: A pressure gauge should be included on the high-pressure side of the pump unit.

6.3 Dry running

The pump must always be connected to the water supply during operation to prevent damage from dry running.

6.4 Disconnection

If the inlet line is disconnected from the water supply, the pump will empty through the disconnected inlet line. When restarting, follow the bleeding procedure outlined in Section 4 (Initial start-up).

6.5 Storage

Storage temperature: Minimum -40°C to maximum +70°C (Min. -40°F to max. +158°F).

For long-term storage at temperatures below freezing, flush the pump with an anti-freeze medium (monopropylene glycol) to prevent internal corrosion or frost damage.

For information on anti-freeze media, contact Danfoss High Pressure Pumps.

Recommended procedure for anti-freeze flushing:

1. Disconnect the water supply to the pump.
2. Empty the pump housing of water through the lower bleeding plug and close it again.
3. Connect the pump to a tank containing an anti-freeze additive. Connect a hose to the pump's inlet port and another hose from the outlet port back to the tank with antifreeze additives.
4. Start and stop the pump quickly to ensure it does not run dry. This protects the pump from internal corrosion and frost.

Storage of pumps that have been in operation:

• For shorter storage periods, flush the pump with permeate for 10 seconds, empty the permeate, and then store it.
• For long-term storage (over 2 months), Danfoss recommends servicing the product, cleaning any biological growth from surfaces, and storing the pump without water.

7. Service and warranty

Warranty

Danfoss APP pumps are designed for extended operation, low maintenance, and reduced lifecycle costs. Provided the pump has been operated according to Danfoss specifications, Danfoss guarantees 8,000 hours of service-free operation, or a maximum of 18 months from the date of production.

Failure to follow Danfoss's system design recommendations can significantly impact the APP pumps' lifespan. Other factors affecting pump performance and lifetime include:

• Insufficient filtration
• Insufficient bleeding and venting
• Operating the pump at speeds outside specifications
• Supplying water at temperatures higher than recommended
• Operating the pump at inlet pressures outside specifications
• Operating the pump at outlet pressures outside specifications
• Incorrect direction of rotation

Pump shutdown

The APP pumps are made of Duplex/Super Duplex materials, offering excellent corrosion resistance. However, it is always recommended to flush the pump with freshwater when the system is shut down.

When stopping the pump for more than one day, flush it with permeate by rotating the pump for 10 seconds. Flushing solely through the flushing valve without rotating the pump is insufficient for internal cleaning. The pump can also be flushed with a biocide compatible with the pump materials (details in the Service guide and Operating manual).

Repair

For any irregular function of the APP pump, please contact Danfoss High Pressure Pumps.

Maintenance

After 8,000 hours of operation, it is strongly recommended to inspect the pump and replace any worn parts, such as pistons and shaft seals, to prevent potential breakdowns. If parts are not replaced, more frequent inspections may be necessary according to guidelines.