General Pump MK2 User manual

MK2/MKS2
Owner’s Manual
• Installation
• Use
• Maintenance
Ref 310199 Rev. A
02-21
General Pump is a
member of the
Interpump Group
MK240A - MK245A - MK250A
MK255A - MK260A - MK265A
MKS255A - MKS260A - MKS265A
MKS240A - MKS245A - MKS250A

GENERAL PUMP A member of the Interpump Group MK2/MKS2 SERIES
Page 2
INDEX
1. INTRODUCTION ..................................................Page 4
2. SYMBOL DESCRIPTIONS ..........................................Page 4
3. SAFETY .........................................................Page 4
3.1 General safety instructions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 4
3.2 High pressure unit safety requirements ..............................Page 4
3.3 Safety during operation ..........................................Page 4
3.4 General procedures for using nozzles ...............................Page 5
3.5 Safety during unit maintenance ....................................Page 5
4. PUMP IDENTIFICATION ............................................Page 5
5. TECHNICAL CHARACTERISTICS ....................................Page 6
6. DIMENSIONS AND WEIGHT ........................................Page 7
7. INFORMATION REGARDING PUMP USE ..............................Page 9
7.1 Water temperature ..............................................Page 9
7.2 Maximum flow and pressure values. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 9
7.3 Lowest operating RPM...........................................Page 9
7.4 Recommended lubricant types and Manufacturers .....................Page 9
8. PORTS AND CONNECTIONS........................................Page 10
9. PUMP INSTALLATION .............................................Page 10
9.1 Installation ....................................................Page 10
9.2 Direction of rotation .............................................Page 11
9.3 Version change and reducer positioning .............................Page 11
9.4 Hydraulic connections ...........................................Page 11
9.5 Pump feeding ..................................................Page 11
9.6 Suction line....................................................Page 11
9.7 Filtering. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 12
9.8 Delivery line ...................................................Page 12
9.9 Internal diameter of hose .........................................Page 12
9.10 V-belt transmission.............................................Page 13
10. START UP AND OPERATION .......................................Page 13
10.1 Preliminary inspections .........................................Page 13
10.2 Starting up ...................................................Page 14
11. PREVENTATIVE MAINTENANCE ....................................Page 14
12. STOPPING THE PUMP FOR LONG PERIODS ..........................Page 14
12.1 Filling the pump with anti-corrosion emulsion or anti-freeze .............Page 14
12.2 Hoses .......................................................Page 14
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02-21

GENERAL PUMP A member of the Interpump Group
Page 3
INDEX (continued)
13. PRECAUTIONS AGAINST FREEZING.................................Page 15
14. WARRANTY TERMS...............................................Page 15
15 TROUBLESHOOTING..............................................Page 15
16. MK2/MKS2 EXPLODED VIEWS AND PARTS ...........................Page 17
17. MK2R/MK2SR PUMP VERSION......................................Page 23
18. MAINTENANCE LOG ..............................................Page 32
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MK2/MKS2 SERIES

Page 4
GENERAL PUMP A member of the Interpump Group
2. SYMBOL DESCRIPTIONS
Warning
Potential Danger
Danger
High Voltage
Danger
Wear protective mask
Danger
Wear goggles
Danger
Wear protective gloves
Danger
Wear protective boots
Read carefully and understand
the manual before operating
the pump
1. INTRODUCTION
This manual describes the use and maintenance
instructions of the MK2 and MKS2 pump, and should be
carefully read and understood before using the pump.
Correct use and adequate maintenance will guarantee
the pumps trouble-free operation for a long time. General
Pump declines any responsibility for damage caused by
misuse or the non-observance of the instructions indicated
in this manual.
Upon receiving the pump, check that it is complete and in
perfect condition.. Should anything be found out of order,
please contact us before installing and starting the pump.
3. SAFETY
3.1 General Safety Indications
The misuse of pumps and high pressure units, and the
non-observance of installation and maintenance
instructions may cause severe injury to people and/or
damage to property. Anyone requested to assemble or
use high pressure units must possess the necessary
competence to do so, should be aware of the
characteristics of the components assembled/used, and
must adopt all the necessary precautions in order to
guarantee maximum safety in any operating condition.
In the interest of safety, no precaution that is reasonably
feasible must be neglected, both by the Manufacturer
and the Operator.
3.2 High pressure unit safety requirements
1. The pressure line must always be equipped with a
safety valve.
2. High pressure unit components, in particular
for those units working outside, must be adequately
protected against rain, frost and heat.
3. The units electrical parts must be adequately
protected from water spray, and must comply with the
specific norms in force.
4. High pressure hoses must be correctly sized for the
unit’s maximum operating pressure, and must only be
used within the pressure range indicated by the hose
manufacturer. The same conditions apply to all other
unit accessories where high pressure is involved.
5. The extremities of high pressure hoses must be
sheathed and fastened to a steady structure in order
to avoid dangerous whiplashes should they burst or
should their connections break.
6. Appropriate safety guards must be provided for the
pump transmission systems (joints, pulleys and belts,
auxiliary drives).
3.3 Safety During Operation
The working area of a high pressure system must be
clearly signaled. Access must be prohibited to non-autho-
rized personnel and, if possible, the area must be fenced
in. The personnel authorized to access this area must be
previously trained, and informed about the risks that may
arise from failures or malfunctions of the high pressure
unit.
Before starting the unit, the operator must check:
1. That the high pressure unit is correctly fed (see
paragraph 9.5).
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GENERAL PUMP A member of the Interpump Group
Page 5
3.3 Safety of Operation (continued)
2. That pump intake filters are perfectly clean;
we advise to use a device that indicates the filters
clogging level.
3. That electrical parts are adequately protected and in
perfect condition.
4. That high pressure hoses do not show apparent signs
of abrasion, and that fittings are in perfect shape.
5. The outer surfaces of the pump may reach high
temperatures. Therefore we recommend to take
precautions to avoid contact with hot parts.
Any anomaly or reasonable doubt that may arise before
or during operation must be promptly reported and ver-
ified by competent personnel. In these cases, pressure
must be immediately released and the high pressure unit
stopped.
3.4 General Procedures For Using Nozzles
1. The Operator must always place his own and other
worker’s safety before any other interest; his actions
should always be governed by good sense and
responsibility.
2. The Operator must always wear a helmet with a
protective visor, waterproof clothing, and appropriate
boots capable of guaranteeing grip on wet pavement.
Note: appropriate clothing will effectively protect against
water spray, but it may not offer adequate protection
against the direct impact of water jets or sprays from a
close distance. Some circumstances may require further
protection.
3. We advise to employ a team of at least two Operators,
able to provide mutual and immediate assistance if
needed, and to rotate their duties in case of long and
heavy work.
4. Access to the work area that is within the water jets’
range must be absolutely forbidden; the area must be
free of objects that may be unintentionally hit by the
pressurized jet, causing damage or dangerous
situations.
5. The water jet must only and always be directed
towards the work area, even during testing or
preliminary inspections.
6. The Operator must always pay attention to the
trajectory of the debris removed by the water jet. If
necessary, adequate side guards must be provided by
the Operator in order to protect anything that may be
accidentally exposed.
7. For no reason must the Operator be distracted during
operation. The personnel that needs to access the
working area must wait for the Operator to suspend
their work, and then immediately make his presence
known.
8. For safety reasons, it is important that each member
of the team is perfectly aware of the intentions and
actions of other team members in order to avoid
dangerous misunderstandings,
9. The high pressure unit must not be started and
brought up to pressure unless each member of the
team is in his designated position, and the Operator
has already directed the nozzle towards the work
area.
3.5 Safety During Unit Maintenance
1. The maintenance of the high pressure unit must be
done within the time intervals indicated by the
Manufacturer, who is responsible for the entire unit’s
compliance with the norms in force.
2. Maintenance must always be carried out by special
ized and authorized personnel.
3. Assembly and disassembly of the pump and its
various components must be performed exclusively
by authorized personnel, using appropriate tools in
order to avoid damage to components
and connections.
4. To guarantee total reliability and safety, always use
original spare parts.
fig. 1
4. PUMP IDENTIFICATION
Each pump (fig. 1) is equipped with a rating plate that
indicates:
Pump model and version
Serial Number
Maximum RPM
Power absorbed Hp-kW
Flow Rate l/mn - GPM
Pressure bar - PSI
Pump model, version and serial number
must always be specified when ordering
spare parts.
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Page 6
5. TECHNICAL FEATURES
MODEL RPM FLOW RATE PRESSURE POWER
GPM l/min PSI Bar Hp kW
MK2 40A 1500 40.4 153 5800 400 159 117
1800 39.4 149 5800 400 155 114
MK2 45A 1500 51.0 193 4350 300 150 110
1800 49.9 189 4350 300 147 108
MK2 50A 1500 63.1 239 3625 250 155 114
1800 61.6 233 3625 250 151 111
MK2 55A 1500 76.4 289 2900 200 150 110
1800 74.5 282 2900 200 146 107
MK2 60A 1500 90.6 343 2465 170 151 111
1800 88.5 335 2465 170 148 109
MK2 65A 1500 106.5 403 2175 150 157 115
1800 104.1 394 2175 150 154 113
MODEL RPM FLOW RATE PRESSURE POWER
GPM l/min PSI Bar Hp kW
MKS2 40A
1500 48.6 184 5800 400 191 140.5
1800 48.3 183 5800 400 190 140
2200 48.1 182 5800 400 189 139
MKS2 45A
1500 61.6 233 4350 300 182 134
1800 61.3 232 4350 300 181 133
2200 61.0 231 4350 300 180 132
MKS2 50A
1500 76.1 288 3625 250 187 137.5
1800 75.6 286 3625 250 186 137
2200 75.3 285 3625 250 185 136
MKS2 55A
1500 92.2 349 2900 200 181 133
1800 94.4 346 2900 200 180 132
2200 90.9 344 2900 200 179 132
MKS2 60A
1500 109.6 415 2465 170 183 135
1800 108.6 412 2465 170 182 134
2200 108.3 410 2465 170 181 133
MKS2 65A
1500 128.7 487 2175 150 190 140
1800 127.9 484 2175 150 189 139
2200 127.1 481 2175 150 187 137.5
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GENERAL PUMP A member of the Interpump Group
Page 7
6. DIMENSIONS AND WEIGHT
For dimensions and weight of MK240A, MK245A, MK250A, MKS240S, MKS245A, and MKS250A pumps,
please refer to fig. 2.
For dimensions and weight of MK255A, MK260A, MK265A, MKS255A, MKS260A, and MKS65A pumps,
please refer to fig. 2a.
fig. 2
fig. 2a
Weight: 877 Lbs./398 Kg.
Weight: 906 Lbs./411 Kg.
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GENERAL PUMP A member of the Interpump Group
6. DIMENSIONS AND WEIGHT (cont.)
For dimensions MK240A, MK245A and MK250A pumps with Hydraulic Pack, please refer to fig. 2b.
For dimensions MK255A, MK260A and MK265A pumps with Hydraulic Pack, please refer to fig. 2c.
Page 8
fig. 2b
fig. 2c
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GENERAL PUMP A member of the Interpump Group
Page 9
7.INFORMATION ABOUT PUMP USE
The MK2/MKS2 pump has been designed to
operate with filtered water (see paragraph 9.7)
and at maximum temperature of 104°F
(40° C).
Other fluids may be used only upon
the approval of The Customer Service
Department .
7.2 Max Flow Rate and Pressure Values
The performance values indicated in the catalog refer to
the maximum performance of the pump. Regardless of
the power used, pressure and maximum RPM values indi-
cated on the plate may not be exceeded unless expressly
authorized by the Customer Service Department.
7.3 Lowest RPM
Any RPM value different from what is indicated in the per-
formance table (see chapter 5) must be expressly autho-
rized by the Customer Service Department.
7.4 Recommended Lubricant Oil Types & Manufacturers
The pump is delivered with lubricant oil compliant with
room temperatures ranging between 32°and 89.6°F (0°
and 30°C ). Some recommended lubricant types are indi-
cated in the table below; these lubricants are treated with
additives in order to increase corrosion protection and
resistance to fatigue. As an alternative, Automotive SAE
85W-90 gearing lubricants may also be used.
7.1 Water Temperature
The max water temperature is 104°F (40°C).
Nonetheless, it is possible to use the pump at
temperatures of up to 140°F (60°C) for short
periods of time. In this case we advise con-
sulting the Customer Service Department.
BRAND TYPE
GENERAL PUMP SERIES 220
ARAL Aral Degol BG220
BP ENERGOL HLP 220
CASTROL
Hyspin VG 220, Magna 220
ELF
POLYTELIS 220
ESSO NUTO 220
FINA Cirkan 220
FUCHS RENOLIN 220
MOBIL DTE OIL BB
SHELL TELLUS C 220
TEXACO RANDO HD 220
TOTAL CORTIS 220
Check the oil level by using the oil level dipstick with
minimum and maximum value notches (1), fig. 3. Refill
if needed from the oil cap (3), fig 3. Correct oil level
inspection is done with the pump at room temperature;
oil is changed with the pump at working temperature, by
removing the rear plug (2), fig 3. Checking and changing
oil is to be carried out as indicated in Chapter 11. The
amount required is 456.5 oz. (13.5 liters).
In any case, oil must be changed at least
once a year since it may deteriorate by
oxidation.
For room temperatures that differ from that
mentioned earlier, follow the indications con-
tained in the diagram below, keeping in mind
that the oil must have a minimum viscosity of
180 cSt.
Exhausted oil must be collected in an
appropriate recipient and disposed of in
appropriate locations. In absolutely no case
may it be dispersed into the environment.
VISCOSITY/ROOM TEMPERATURE DIAGRAM
fig. 3
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GENERAL PUMP A member of the Interpump Group
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8. PORTS AND CONNECTIONS
MK2 Series pumps (see fig. 4 and 4a) are provided with:
1. 2 inlet ports “IN”, 2” NPT (MK2/S 40A, 45A, 50A).
2 inlet ports “IN”, 3” NPT (MK2/S 55A, 60A, 65A).
The line can be connected to either of the two inlet
ports; the ones not being used must be hermetically
sealed.
2. 2 outlet ports “OUT”, Ø 1” NPT-F (MK2/S 40A, 45A,
50A).
2 outlet ports “OUT”, Ø 1-1/4” NPT-F (MK2/S 55A, 60A,
65A).
3. 1 drain port “DRAIN” with G1/2” hole in the lower
cover to monitor any water leakage due to wear of the
pressure packings. In case of leaks, please consult
the repair manual.
This hole must always be kept open.
9.2 Direction of rotation
An arrow situated on the crankcase near the shaft
indicates the correct direction of rotation. Standing in front
of the pump head, the direction of rotation must be as
shown in fig. 5.
The pump’s shaft (PTO) must not be rigidly
connected to the motor unit. The following
transmission types are suggested:
• Flexible joint
• Cardan Joint (please respect the maximum
working angles indicated by the manufacturer)
• Belts; for correct application, please contact the
Customer Service Department.
9. PUMP INSTALLATION
9.1 Installation
The pump must be installed in a horizontal position using
the correct perforated feet Ø .649in (16.5 mm). The base
must be perfectly flat and sufficiently rigid in order to avoid
bending and misalignments on the pump/transmission
coupling axis due to the torque applied during operation.
The pump is equipped with two lifting eyebolts to facilitate
installation, as shown in the following figure.
The lifting eyebolts must not be removed.
The eyebolts are for lifting the pump only and
mys must never be used to handle additional
loads.
fig. 4
fig. 4a
Replace the oil filler plug located on the crank-
case with the dipstick.
The dipstick must always be reachable, even
when the unit is assembled.
fig. 5
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GENERAL PUMP A member of the Interpump Group
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9.4 Hydraulic Connections
In order to isolate the system from the vibrations pro-
duced by the pump, we advise to build the first section of
the duct near the pump (both for intake and delivery) with
flexible hose. The consistency of the intake section must
allow to avoid deformation caused by the depressurization
produced by the pump.
9.5 Pump Feeding
MK2/MKS2 pumps must always be installed under pos-
itive head, i.e. they must receive water by gravity or by
forced feeding, and never suck from a lower level. The
pumps can tolerate minimum NPSH even as low as 1 m.
(3.28 ft.), however, to obtain a better volumetric efficien-
cy and above all to avoid cavitation, the minimum NPSH
available, measured at the pump inlet flange, will have to
be at least equal or higher than the values shown in the
chart below.
9.6 Suction Line
For the pump’s correct operation, the suction line must
have the following characteristics:
1. Minimum internal diameter as indicated in the diagram
in paragraph 9.9, and in any case equal or greater
than the pump head’s value.
Along the duct, avoid localized diameter reduc-
tions that may cause pressure drops with sub-
sequent cavitation. Absolutely avoid 900elbows,
connections with other hoses, bottlenecks, count-
er-slopes, upside down “U” shaped curves, “T”
connections.
2. The selected lay-out must allow to avoid cavitation.
3. It should be perfectly airtight, and built in a way that
guarantees perfect sealing over time.
4. Avoid pump emptying when stopping (even partial
emptying).
5. Do not use hydraulic-type fittings, 3 or 4 way fittings,
adapters, etc., since they may hinder the pump’s
performance.
6. Do not install Venturi tubes or injectors for detergent
intake.
7. Avoid the use of standing valves, check valves, or any
other type of one-way valves.
8. Do not connect the by-pass line from the valve directly
to the pump suction line.
9. Provide appropriate baffle plates inside the tank in
order to avoid water flows coming from both the by-
pass and feeding lines may create turbulence near
the tank’s outlet port.
10. Make sure that the suction line is perfectly clean
inside before connecting it to the pump.
11. The pressure gauge for checking booster pressure
must be installed near the plunger pump’s outlet port,
and always after the filters.
The version may be changed only by special-
ized and authorized personnel by carefully
following the instructions in the repair manual.
9.3 Version Change and Reducer Positioning
A right version pump is defined when: observing the
pump from the head side, the PTO shank of the pump
shaft is on the right side.
A left version pump is defined when: observing the pump
from the head side, the PTO shank is on the left side.
See fig. 5.
Furthermore, it is possible to position the reducer in 5
different positions, both on the right and left sides, as
shown in fig. 6.
The reducer’s position may be changed only
by specialized and authorized personnel by
carefully following the instructions in the
repair manual.
fig. 6
MK240A
MKS240A
MK245A
MKS245A
MK250A
MKS250A
MK255A
MKS255A
MK260A
MKS260A
MK265A
MKS265A
NPSHr
(ft) 14.8 18 21.3 24.6 26.2 29.5
For the pumps with higher displacement (MK255A-60A-
65A), it is strongly recommended to use a booster pump
to avoid cavitation, in view of the geometry on the hydrau-
lic section and of the remarkably high flow rates.
The booster pump must have the following specifications:
flow rate at least double the rated flow rate of the pump,
and pressure between 30 to 45 PSI (2 to 3 Bar). These
feeding conditions must be respected in all running condi-
tions.
Booster start-up must always precede
plunger pump start-up. In order to protect the
pump, we advise to install a pressure switch
on the feeding line after the filters.
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MK2/MKS2 SERIES

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GENERAL PUMP A member of the Interpump Group
The filter must be installed as close as possible to the
pump, should allow easy inspection and have the
following characteristics:
1. Minimum capacity 3 times greater than the pump’s
rated flow value.
2. Filter port diameters must not be smaller than the
pump inlet ports.
3. Filtration degree ranging between 200 and 360 µm.
9.7 Filtering
On the suction line, install two filters as indicated in fig. 7
and fig. 7/a.
With the manual adjustment valve:
With the pneumatic adjustment valve:
In order to guarantee correct pump operation,
it is important to plan periodical cleaning of
the filter depending on actual pump usage,
water quality and real clogging conditions.
9.8 Delivery Line
To obtain a correct delivery line, please comply with the
following installation instructions:
1. The internal diameter of the pump must allow to guar
antee correct fluid speed; see digram in paragraph 9.9
2. The first section of the hose connected to the pump
must be flexible in order to isolate pump vibrations
from the rest of the system.
3. Use high pressure hoses and fittings that guarantee
wide safety margins in any working condition.
4. Install a safety valve on the delivery line.
5. Use pressure switches suitable for the pulsating loads
typical of plunger pumps.
6. In the design phase, take into proper account the
pressure drop along the line, since this causes a
reduction in usage pressure with respect to the value
measured at the pump.
7. If the pump pulsations are harmful for particular appli
cations, install an appropriately sized pulsation damp
ener on the delivery line.
9.9 Internal Diameter of the Hose Line
To determine the internal diameter of the hose, please
refer to the following diagram.
Suction Hose
With a flow rate of ~106 GPM (400 l/mn) and water speed
of 1 m/sec. the diagram line that connects the two scales
intersects the central scale, indicating the diameters, at a
value of ~ 3.5 inch (90 mm).
Delivery Hose
With a flow rate of ~106 GPM (400 l/mn) and water speed
of 5.5 m/sec. The diagram line that connects the two
scales intersects the central scale, indicating the diame-
ters at a value of ~ 1.6 inch (40 mm).
Optimum speed values:
• Suction: ≤ 1 m/sec.
• Delivery: ≤ 5.5 m/sec.
fig. 7
fig. 7a
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GENERAL PUMP A member of the Interpump Group
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9.10 V-belt Transmission
As indicated in paragraph 9.1, only in exceptional cases
may the pump be driven by a v-belt system. For cor-
rect lay-out sizing, please contact our Customer Service
Department.
The diagram does not take into account the hose
and valve resistance, the pressure drop due to
the pipe length, the viscosity and the temperature
of the pumped fluid. If necessary, contact our
Customer Service Department.
10. START-UP AND OPERATION
10.1 Preliminary Inspections
Before Start-up Be sure that:
The suction line is connected and up to pres-
sure (see Chapter 9) the pump must never
run dry.
1. The suction line must be perfectly airtight.
2. All the On-Off valves between the pump and
the feeding source are completely open. The
delivery line must discharge freely in order to
allow the air in the pump to be ex-pulsed
easily, thus facilitating pump priming.
3. All suction/delivery connections and fittings
must be correctly tightened.
4. Coupling tolerances on the pump/transmis
sion axis (half-joint misalignment, Cardan
inclination, belt tightening, etc.) must remain
within the limits indicated by the transmission
Manufacturer.
5. The pump’s oil level must be verified
using the correct dipsticks (position 1, fig 8).
In case the pump has not run for a long
period of time, recover the correct operation
of the suction valves by opening the three
valve-lifting devices (see position 2, fig. 9). Be
sure to reclose the valves before the pump
start-up. See fig. 10 for the valve positions.
fig. 8
fig. 9
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10.2 Start-up
1. When starting the pump for the first time, check for
the correct direction of rotation.
2. The pump must be started off-load.
3. Verify correct feeding pressure.
4. During operation, check that the rotating speed does
not exceed the rated value.
5. Before putting the pump under pressure let it run for
at least 3 minutes.
6. Before stopping the pump, release the pressure by
acting on the adjustment valve or on any discharging
device.
In case of priming problems caused by insuf-
ficient feeding, it’s possible to intervene by
removing the three front caps on the head
(see position 3, fig. 11).
11. PREVENTIVE MAINTENANCE
PREVENTIVE MAINTENANCE
EVERY 500 HOURS EVERY 1500 HOURS
Check oil level Change oil
Check / Replace:
• Valves
• Valve seats
• Valve springs
• Valve guides
Check / Replace:
• H.P packings
• L.P. packings
To guarantee pump reliability and efficiency, respect the
maintenance intervals as indicated in the table below.
12. STOPPING THE PUMP FOR LONG PERIODS
12.1 Filling the Pump With An Anti-Corrosion
Emulsion or Anit-freeze By Using An External
Diaphragm Pump As In The Layout Shown in
Paragraph 9.7.
a) Close the filter draining, if open.
b) Be sure that the connecting hose is clean, spread
with grease and connect it to the high pressure outlet
port.
c) Fit a suction hose to the membrane pump. Open the
pump suction connection and fit hose between it and
the membrane pump.
d) Fill the container with the solution/emulsion.
e) Put the free extremities of the suction line and the
high pressure outlet hose inside the container.
f) Start up the diaphragm pump.
g) Pump the emulsion until it comes out of the high
pressure hose.
h) Continue pumping for at least another minute; if
needed, the emulsion can be reinforced by adding,
for example, Shell Donax
i) Stop the pump, remove the hose from the suction
connection and close it with a plug.
j) Remove the hose from the high pressure outlet port.
Clean, grease and plug both connections and the
hoses.
12.2 Hoses
a) Before greasing and protecting the hoses according
to the previously described procedure, dry the con
nections using compressed air.
b) Cover with polyethylene.
c) Do not wrap them too tightly; be sure there is no
bending.
fig. 14
fig. 10
fig. 11
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MK2/MKS2 SERIES

GENERAL PUMP A member of the Interpump Group
13. PRECAUTIONS AGAINST FREEZING
In areas and periods of the year where there is
risk of freezing, follow the instructions indicated
in Chapter 12 (see paragraph 12.2).
In the presence of ice, in no case must the
pump be started until the entire circuit has
been completely thawed out; not complying
with this indication may cause serious
damage to the pump.
14. WARRANTY TERMS
The pump is guaranteed for a period of 12 months from
the delivery date or for 1000 hours of operation, with the
exception of parts subject to wear. In any case, please
refer to the contract terms for other warranty conditions.
The warranty is void if:
a) The pump has been used for purposes that differ
from that agreed.
b) The pump has been fit with an electric or diesel
engine with performance greater than that indicated
in the table.
c) The required safety devices were un-adjusted or dis
connected.
d) The pump was used with accessories or spare parts
not supplied by General Pump.
e) Damage was caused by:
1) improper use
2) the non-observance of maintenance instructions
3) use not compliant with operating instructions
4) insufficient flow rate
5) faulty installation
6) incorrect positioning or sizing of the hoses
7) non-authorized design changes
8) cavitation
15. TROUBLESHOOTING
The pump does not produce any noise at
start-up:
• The pump is not primed and is running dry
• There is no water in the inlet line
• The valves are blocked
• The delivery line is closed and does not allow
the air in the pump to be discharged
The pump pulses irregularly (knocking):
• Air suction
• Insufficient feeding
• Bends, elbows, fittings along the suction line
obstruct the fluid’s passage
• The inlet filter is dirty or too small
• The booster pump, where provided, supplies
insufficient pressure or flow rate
• The pump is not primed due to insufficient
head or the delivery line is closed during
priming
• The pump is not primed due to valve seizing
• Worn valves
• Worn pressure packings
• Incorrect operation of the pressure adjust
ment valve
• Transmission problems
The pump does not deliver the rated flow / is
noisy:
• Insufficient feeding (see the causes listed
above)
• RPM are less than the rated value
• Excessive amount of water by-passed by the
pressure adjustment valve
• Worn valves
• Leakage from the pressure packings
• Cavitation due to:
1) Wrong sizing of the suction hose/
undersized diameters
2) Insufficient flow rate
3) High water temperature
Insufficient pump pressure:
• The nozzle (or has become)too large
• Insufficient RPM
• Leakage from the pressure packings
• Incorrect operation of the pressure adjust-
ment valve
• Worn valves
Page 15
Ref 310199 Rev. A
02-21
MK2/MKS2 SERIES

GENERAL PUMP A member of the Interpump Group
Page 16
15. TROUBLESHOOTING (continued)
Overheated pump:
• The pump is overloaded (pressure or RPM
exceed the rated values)
• Oil level is too low, or the oil is not of a suit
able type, indicated in Chapter 7 (see para
graph 7.4)
• Incorrect alignment of the joint or pulleys
• Excessive inclination of the pump during
operation
Pump vibrations or knocking:
• Air suction
• Incorrect operation of the pressure adjust
ment valve
• Valve malfunction
• Irregular drive transmission motion
Ref 310199 Rev. A
02-21
MK2/MKS2 SERIES

GENERAL PUMP A member of the Interpump Group
Page 17
16. EXPLODED VIEW AND PARTS LIST
MK240A, MK2S40A, MK245A, MKS245A, MKS250A, MKS2S50A
Ref 310199 Rev. A
02-21
MK2/MKS2 SERIES
MK2 MKS2 HP

GENERAL PUMP A member of the Interpump Group
Page 18
Item Part No. Description QTY.
1 F74120501 Manifold, MK245A, MK250A, MKS245A, MKS250A NPT 1
2 F10744401 Suction Valve Device 3
3 F36206766 Inlet Valve Seat 3
4 F90526000 Anti-extrusion Ring, Suction Valve Spring61.2 x 67 x 2 3
5 F90389000 O-ring, Ø 50.47 x 2.62 6
7 F36208801 Suction Valve Spring 6
8 F94760000 Spring, Ø 28.3 x 30.7 3
9 F36206101 Suction/Delivery Valve Guide 6
10 F36715101 Suction Valve Assembly 3
11 F74210651 Spacer, Valve Guide 3
12 F90358400 O-ring, Ø 10.82 x 1.78 3
13 F98204600 Plug, G 1/4” x 13 3
14 F36206966 Valve Seat 3
15 F90526500 Anti-extrusion Ring, Ø 51.7 x 56.2 x 1.5 3
16 F90527600 Anti-extrusion Ring, Ø 67.5 x 72 x 1.5 3
17 F90391100 O-ring, 66.35 x 2.62 6
18 F94760500 Spring, Ø 28.5 x 32 3
19 F36715301 Outlet Valve Assembly 3
20 F74211070 Valve Plug, H.P. 3
21 F90528000 Anti-extrusion Ring, Ø 67.7 x 72.2 x 1.5 3
22 F94775000 Spring, Ø 58 x 45.4 3
23 F74210866 Ring, Valve Seat 3
24 F74210315 Valve Cover, H.P. 1
25 F99522200 Screw, M16 x 180 8
26 F99514700 Screw, M16 x 55 8
27 F99385000 Plunger Screw 3
28 F96710500 Washer, Ø 10x18x0.9 3
29 F90410200 O-ring, Ø 58.74 x 3.53 9
30
F74211156 Plunger Sleeve, MK240A, MKS240A 3
F74211256 Plunger Sleeve, MK245A, MKS245A 3
F74211356 Plunger Sleeve, MK250A, MKS250A 3
31
F74040009 Plunger, MK240A, MKS240A 3
F74040109 Plunger, MK245A, MKS245A 3
F74040209 Plunger, MK250A, MKS250A 3
32 F90372200 O-ring,Ø 96 x 2 6
33
F74100092 Head Ring, MK240A, MKS240A 3
F74100192 Head Ring, MK245A, MKS245A 3
F74100292 Head Ring, MK250A, MKS250A 3
34
F90283200 H.P. Packing, MK240A, MKS240A 3
F90285000 H.P. Packing, MK245A, MKS245A 3
F90286300 H.P. Packing, MK250A, MKS250A 3
35
F90283800 Restop Ring, MK240A, MKS240A 3
F90284800 Restop Ring, MK245A, MKS245A 3
F90286500 Restop Ring, MK250A, MKS250A 3
36
F74211768 Gasket Holder, MK240A, MKS240A 3
F74211868 Gasket Holder, MK245A, MKS245A 3
F74211968 Gasket Holder, MK250A, MKS250A 3
37
F90282800 L.P. Packing, MK240A, MKS240A 3
F90284600 L.P. Packing, MK245A, MKS245A 3
F90286000 L.P. Packing, MK250A, MKS250A 3
38 F74213351 Wiper 3
39 F90386500 O-ring, Ø 29.82 x 2.62 3
40 F90382500 O-ring, Ø 10.78 x 2.62 3
41 F99183700 Screw, M6 x 14 14
42 F74150122 Upper Cover 1
43 F74150222 Lower Cover 1
44 F90450000 O-ring, Ø 266.06 x 5.34 2
45 F74050336 Plunger 3
46 F74213171 Plunger Oil Seal Cover 3
47 F90391400 O-ring, Ø 72.69 x 2.62 3
48 F90167900 Ring, Ø 40 x 52 x 7 3
49 99188400 Screw, M6x20 12
50 F99369700 Screw, M10 x 35 6
51 F79050443 Plunger Guide 3
F79050543 Plunger Guide, +1.0 3
52 F98233300 Oil Plug 1
53 F99441000 Connecting Rod Screw, M12 x 1.25 x 87 6
54 F99304500 Screw, M8 x 18 6
55 98218700 Plug, G 1/2” x 13 1
56 F96751400 Washer, Ø 21.5 x 27 x 1.5 1
57 F91870000 Bearing 1
Item Part No. Description QTY.
58
F10088055 Pinion, Z30 R. 1.600 - Elicoid, MK2 1
F10088255 Pinion, Z24 R. 2.208 - Elicoid, MKS2 1
F10088355 Pinion, Z21 R. 2.667 - Elicoid, MK2 MKS2 1
F10088435 Pinion, Z18 R. 3.278 - Elicoid, MK2 MKS2 1
59 F91861000 Bearing 1
60 F90392650 O-ring, 126.67 x 2.62 1
61 F91503000 Key, 16 x 10 x 90 1
62 F90180000 Ring, Ø 60 x 80 x 8 1
63 F74217322 Gearbox Flange 1
64 F99433500 Screw, M12 x 50 2
65 99368400 Screw, M10 x 30 4
66 F91512000 Pinion Key 1
67 F74225255 Gear Stop 1
68 F74020235 Crankshaft 1
69
F10088635 Gear, Z48 R. 1.600 - Elicoid, MK2 1
F10088835 Gear, Z53 R. 2.208 - Elicoid, MKS2 1
F10088935 Gear, Z56 R. 2.667 - Elicoid, MK2 MKS2 1
F10089035 Gear, Z59 R. 3.278 - Elicoid, MK2 MKS2 1
70 F99373000 Screw, M10 x 50 10
71 F74217413 Gearbox Cover 1
72 F90417300 O-ring, 338.00 x 3.60 1
73 F97623000 Retainer Pin, Ø 12 x 40 2
74 F74217513 Gearbox Housing 1
75 F99430500 Screw, M12 x 40 6
76 F10090735 Gear, Z56 R. 2.667 - Elicoid, SAE-D 1
F10090735 Gear, Z60 R. 3.75 - Elicoid, SAE-C 1
77 F91885000 Bearing 1
78 F74213084 Gasket, Lateral 2
79 F74010113 Pump Body 1
80 F74030201 Connecting Rod Assembly 3
81
F90930000 Bearing, Lower 3
F90930100 Bearing, +0.25, Lower 3
F90930200 Bearing, +0.50, Lower 3
82
F90931000 Bearing, Upper 3
F90931100 Bearing, +0.25, Upper 3
F90931200 Bearing +0.50, Upper 3
83 F74160022 Crankcase Cover 1
84 F90416000 O-ring, Ø 304.39 x 3.53 1
85 F91885200 Bearing 1
86 F74150022 Bearing Cover 1
87 F93080000 Ring Nut 1
88 F96830000 Washer, MB 1
89 F91880000 Bearing Bushing 1
90 F99428000 Screw, M12 x 30 8
91 F98209200 Dipstick 2
92 F93105000 Eye Bolt 2
93 F90069700 Ring 6
94 F97745000 Piston Pin, Ø 35 x 64 3
95 F90383300 O-ring, Ø 13.95 x 2.62 2
96 F74120715 Manifold, MK240A, MKS240A 1
97 F36209051 Internal Valve Guide 6
98 F74215156 Bushing 3
99 F90526880 Anti-extrusion Ring, Ø59x65x1.5 6
100 F90917300 Bushing 3
101 F74120601 Packing Stack, MK245A, MK250A, MKS245A, MKS250A 1
102 F74120301 Packing Stack, MK240A, MKS240A 1
103 F10090555 Pinion, Z21 R. 2.667 Elicoid 1
104 F10090920 Motor Flange, SAE-D 1
105 F10090820 Motor Flange, SAE-C 1
106 F90206500 Plug, Ø 17 2
107 F74217834 Screw, M6 x 30 1
108 F74217671 Ring, Ø 55 1
109 F10090655 Pinion, Z16 R. 3.375 Elicoid 1
110 F74217171 Ring, Ø 50 1
111 F70227034 Screw, M6x12 1
112 F92202500 Nut, M6x5 1
113 F96738000 Washer, Ø 17.5 x 23.0 x 1.5 2
114 F98208600 Plug, G 3/8” x 12 2
115 F74606201 Complete Piston Guide 3
116 F99366800 Screw, M10 x 25 6
Ref 310199 Rev. A
02-21
MK2/MKS2 SERIES

REPAIR KITS
KIT NUMBER
F2052 (MK240A
MKS240A)
Plunger Packing Kit
F2053 (MK245A
MKS245A)
Plunger Packing Kit
F2054 (MK250A
MKS250A)
Plunger Packing Kit
F2055
Valve Kit
F2056 (MK240A
MKS240A)
Complete Seals Kit
F2057 (MKS45A
MKS245A)
Complete Seals Kit
F2058 (MK250A
MKS250A)
Complete Seals Kit
F2076
(F2077 +0.25)
(F2078 +0.50)
Connecting Rod Kit
Positions Included 29, 32, 34,
35, 37, 40
29, 32, 34,
35, 37, 40
29, 32, 34,
35, 37, 40 4, 5, 17, 21
4, 5, 12, 15, 16,
17, 21, 28, 29, 32, 34,
35, 37, 39, 40, 44, 47,
48, 60, 62, 72, 78,
84, 95
4, 5, 12, 15, 16,
17, 21, 28, 29, 32, 34,
35, 37, 39, 40, 44, 47,
48, 60, 62, 72, 78,
84, 95
4, 5, 12, 15, 16,
17, 21, 28, 29, 32, 34,
35, 37, 39, 40, 44, 47,
48, 60, 62, 72, 78,
84, 95
81, 82
GENERAL PUMP A member of the Interpump Group
TORQUE SPECS
No. Ft. Lbs Nm
2 29.5 40
13 29.5 40
25 245.6 333
26 245.5 333
27 29.5 40
41 7.4 10
49 7.4 10
50 29.5 45
53 55.3 75
54 14.7 20
55 29.5 40
58 33.2 45
64 54.2 73.5
65 59 80
75 54.2 73.5
90 29.5 40
107 7.4 10
111 7.4 10
114 29.5 40
116 33.2 45
Page 19
Ref 310199 Rev. A
02-21
MK2/MKS2 SERIES

GENERAL PUMP A member of the Interpump Group
16. EXPLODED VIEW AND PARTS LIST
MK255A, MKS255A, MK260A, MKS260A, MK265A, MKS265A
Ref 310199 Rev. A
02-21 Page 20
MK2/MKS2 SERIES
MK2 MKS2 LP