QED MP50 User manual

Part No. 95258 2-15-10
MP50
CONTROLLER/COMPRESSOR
MODEL
PATENT PENDING
O
U
asics
Manual
Instruction
P.O. Box 3726 Ann Arbor, MI 48106-3726 USA
1-800-624-2026 Fax [phone]
[e-mail] www.qedenv.com

MP50
Controller
Optional
MP30 Drawdown
Meter
Well
Cap
Tubing
Pump Air Supply
Pump Discharge
Well Wizard
Bladder
Pump
R
MP50 Basic Setup

Contents
Topic Page
Safety Warnings
Conventions and Diagrams
Introduction / Quick-Start
Turning the MP50 On
Opening Display
MicroPurge Mode
Using CPM
Sampling
Use with the MP30 Level Sensing Water Level Meter
ID Mode
User Time Set (MN) Mode
MP50 Battery
Troubleshooting
MP50 Specifications
QED Service Contacts
QED Warranty
Appendix 1 ID Data Table
1
1
4
7
6
7
8
8
10
11
14
15
16
17
18
19
20
21
Bladder Pump Operation in Low-Submergence Applications

Safety Warnings
1
Safety warnings
Diagrams and Conventions used in the Text
MP50 Panel Layout:
Compressed air - Use caution when working with compressed air or gas. Compressed gas
cylinders are under extreme pressure and can cause unrestrained hoses to whip about danger-
ously. Do not over pressurize your controller. Failure to operate the controller within the pres-
sure limits could result in failure. Read all operating instructions before operating the MP50
controller.
Warning - Do not disassemble the pneumatic pump while it is connected to a compressed gas
source. Dangerous pressures could cause injury.
Pressure
Gauge
Battery
Cover
Flow
Throttle
Connector for optional
MP30 Drawdown Control
MP50 Control
Keypad and
display
Discharge
cycle
indicator
Controller
To Pump
Connection
Compressor
Fan
Compressed
Gas Source
Connection
Battery
Connectors

Diagrams / Conventions
2
Diagrams And Conventions Used In The Text (Cont.)
MP50 Control Keys:
MODE
I I
CPM Button (also scroll for
item selects)
UP Button, faster pumping
(also increase item)
DOWN Button, slower
pumping (also decrease
item)
CYCLE Button
MODE Button (also battery
check)
PAUSE Button (also
manual sample)
MicroPurge Basics Controller
MP Micro Purge
ID ID Time Set MN Manual Time Set LVL LevelShutoff
CYCLE
I I
MODE
CPM/Value Flow/Value Flow/Value
Hold/Sample
/Cycle
Start/Stop ID/MN/MP/
Battery
Mode CPM
ID
Time Refill
Discharge
00.1
103 10.0
MP CPM4 >05.0
DE
CYCLE
In MP Mode
Cycle Per Minute
key - Changes
cycle per minute Scrolls cursor
Faster key -
Speeds up flow
Slower key -
Slows down
flow
Pause key -
Pauses flow for
sampling
Mode key -Selects
the operation
mode. Also battery
check
Cycle key -Selects
Start and Stop of
pump cycling
Changes a value
at the cursor
location
Changes a value
at the cursor
location
In Other Modes

Diagrams / Conventions
Diagrams And Conventions Used In The Text (Cont.)
MP50 Display:
00.1
MP CPM4 >05.0
103 10.0 Discharge time
setting in
seconds
Indicates if
pump is
Refilling or
Discharging
Cycles per
minute setting
The mode the
controller is in
Refill time
setting in
seconds
Time
remaining
in the cycle ID for time
settings
Abbreviations:
CPM
MP
ID
HELD
MN
BAT
LVL
>
Cycles Per Minute
MicroPurge Mode
ID Time Set Mode
Held In A Cycle
Manual Time Set Mode
Battery
Level Pause
Indicates Refill Or Discharge Cycle
3

Introduction / Quick Start
4
Introduction / Quick Start
Insert Batteries: Remove the battery cover on the top of the MP50. Insert 3, AAalkaline bat-
teries into the battery holder and carefully replace the holder in the carrier. Replace the
battery cover and tighten the 4 screws. Batteries should last for about 6-8 weeks of typical
full-time field use. If the MP50 will be stored longer than about 3 months, the alkaline batteries
should be removed to prevent leakage.
Introduction: The MP50 Micro Purge Basics Controller/Compressor is used to operate QED
Well Wizard™ bladder sampling pumps to purge and sample ground water. The MP50 has
specific design features to make MicroPurge ™ sampling easier. These features include:
MicroPurge Mode Operation Simple Increase / Decrease keys allow you to easily set
the flow rate you need for each well.
ID Time Set Mode Operation Quickly recalls pre-determined settings for each well by
specifying a 3-digit ID.
Level Delay Interface The controller plugs into the optional MP30 MicroPurge Draw-
down / Water Level Meter to provide direct feedback of well drawdown and to pause
pump operation until the level recovers.
The optional MP30 MicroPurge Drawdown / Water Level Meter plugs into the MP50 to pro-
vide water level feedback. The MP30 uses a standard conductivity probe to detect the
ground water surface and a marked tape allowing the user to measure the depth. When the
meter is set in MicroPurge mode, the probe is lowered a specific distance below the static
water level and fixed in this position. During well sampling if the water level drops below
the user-set probe position, the MP50 is paused which prevents further drawdown by the
pump. Once the level recovers the MP50 begins pump operation again, starting in the pump
refill cycle. Use of the MP50 with the MP30 is detailed later in this manual.

Introduction / Quick Start
5
Opening the MP50 case turns power ON.
Note: It may take up to 20 seconds for the unit to power up.
Note: An option to use an external air source is built into the MP50. To
use external air source (rather than the built-in air compressor) simply
connect the air source to the “Air In” port.
Select desired Cycles Per Minute (CPM) with (default value is 4
CPM, lower CPM for deeper wells, higher CPM possible with shallow
wells- .
Turn throttle to set depth on gauge to 10-20 feet deeper than the pump
location in the well.
See Page 6)
Cycle
I I
Press to START pumping.
When water discharge begins, adjust throttle until a slow, steady flow-
stream is achieved.
Press keys to set the desired purge flow rate.
To collect samples, continue purge flow, or use key to directly
control sample flow and pause.
Quick Start: Attach Red Positive (+) cable clamp to the Positive (+)
terminal of battery. Attach Black Negative (-) cable clamp to the
Negative (-) terminal of battery. Connect the light blue coiled pump hose
to the fitting labeled “AIR OUT” on the MP50. Turn the controller throttle
until the gauge reads the approximate depth of the sample pump (See
Page 6) Follow instructions on the battery panel:
Note: A moisture vent is provided and located on the side of the MP50
case. Excessive accumulation of moisture can impede proper operation
of the MP50. During cold and/or damp weather conditions, it is
recommended that the moisture vent be pushed at frequent intervals
during operation of the MP50.

6
Bladder Pump Operation In Low-Submergence
QED sampling bladder pumps fill by hydrostatic pressure. As the inside of the pump's bladder
fills with water, the bladder expands. This filling and expanding of the bladder is referred to as
the "refill" half of the pump cycle. When air pressure is applied to the outside of the bladder, the
bladder is squeezed, forcing the water up the discharge tubing. This is referred to as the
"discharge" half of the pump cycle. In low-submergence applications, there is less water pres-
sure available to expand the bladder during the refill.
This can result in a smaller volume of water being pumped with each pump cycle because the
bladder may not fully expand.
As a result of the lower volume per cycle, more time will be required to bring the water to the
surface. An easy way to verify that the pump is working, prior to the water reaching the surface,
is to submerge the pump's discharge tubing in a beaker of water. Each time the pump goes into
discharge, air in the discharge tubing, which is displaced as the water level in the tubing rises,
can be seen as air bubbles coming from the end of the tubing. To optimize the pumping rate,
the refill time should be set long enough to achieve the maximum volume of air bubbles on
each pump cycle, and the discharge time should be set long enough to ensure that the air has
stopped bubbling out of the tube before the pump controller switches back into refill.
In low submergence wells, it is critical that the air pressure driving the pump not be more
than 10-15psi higher than the minimum requirement of 0.42psi per foot of pump depth.
Higher pressures than this can cause the bladder to be squeezed too tightly during discharge,
a condition which can prevent the bladder from expanding during refill. To avoid this condition
in deeper wells, it is suggested that the air pressure applied to the pump be gradually increased
as the water level in the pump's discharge tubing rises. It is recommended that the air pressure
be set at 15 psi initially, and slowly increased in increments of 10 psi as needed until the water
reaches the surface. Submerging the end of the discharge tubing under water as described
above will verify whether the air pressure is set high enough.
.
Bladder Pump Operation In Low-Submergence Applications
Pump submergence is defined as the height of the static water column above the top of the
pump. In wells in which this water column height is 5 feet or less, the pump is considered to be
in a low-submergence application.

7
Operation
Turning the MP50 Display On - The MP50 is powered on automatically by opening the lid.
The MP50 displays an opening screen for 5 seconds, after which it displays the default Micro-
Purge screen. At this point the MP50 is in MicroPurge mode (MP) but not cycling the pump.
This initial state allows the user to adjust time and throttle settings before the pump starts to
operate. Pressing the Cycle key begins pump cycling. Times and modes may be adjusted
while the pump is cycling or before. Pressing the Cycle key a second time will stop pump
cycling.
Note: all user-entered time settings are lost when the MP50 is turned off. Also, the MP50
automatically powers down when the lid is closed, so make sure the MP50 is stored with its
lid closed.
Opening Display - The opening display is shown for 5 seconds and displays the controller
name, the version number and the battery voltage, as shown in Figure 1. Figure 1 shows that
the battery is GOOD, that the battery voltage is 4.20 volts and that the software version in the
cont-roller is 1.0. Battery voltage must be greater than 3.6 volts for the unit to operate. If the
unit fails to cycle replace the 3-AA batteries with fresh cells. The opening screen is displayed
for 5 seconds, if you wish to by pass the opening screen, hitting any key, such as the CPM key
will bring you to the default MP display.
Figure 1 Opening Screen
Operation
MicroPurge Basics Controller
MP Micro Purge
ID ID Time Set MN Manual Time Set LVL LevelShutoff
CYCLE
I I
MODE
CPM/Value Flow/Value Flow/Value
Hold/Sample
/Cycle
Start/Stop ID/MN/MP/
Battery
Mode CPM
ID
Time Refill
Discharge
QED
MP10
V1.0
BAT GOOD 4.20
DE

MicroPurge Mode Most MP50 users will leave the controller in the default MicroPurge (MP)
mode. See Figure 2 for an example of the MP50 in MP mode. MP mode lets you to use the
UP and DOWN keys to directly increase and decrease pump flow rates. The MP50 has a
broad range of other CPM settings to ensure the availability of a time setting that will match
your specific conditions. MP mode also displays an ID, with a value of 1 to 165 that matches
the flow settings (CPM and refill and discharge times you have set). This ID should be noted
alongside the well identification (QED provides custom weatherproof ID badges for purchasers
of our MP series of well caps) for quick setting of the optimal controller settings on the next
visit by using the MP50 in ID mode.
Figure 2 MP50 MicroPurge Mode
Using CPM The MP50 introduces a revolutionary, simpler way to control bladder pump flow
rate and achieve the low-flow method used by experts. Up/down arrow keys are used to adjust
pump flow even at very low rates, with excellent control and repeatability.
8
Operation
MicroPurge Basics Controller
MP Micro Purge
ID ID Time Set MN Manual Time Set LVL LevelShutoff
CYCLE
I I
MODE
CPM/Value Flow/Value Flow/Value
Hold/Sample
/Cycle
Start/Stop ID/MN/MP/
Battery
Mode CPM
ID
Time Refill
Discharge
00.1
103 10.0
MP CPM4 >05.0
DE
With previous bladder pump controllers, a leading low-flow technique called for selecting the
number of pump cycles per minute, then adjusting the bladder pump discharge and refill times
to achieve the desired volume per cycle. These adjustments were interrelated, complex, and
varied by operator. The new MicroPurge Mode (MP) of the MP50 builds in a "cycles per
minute", or CPM, method of flow control.

Operation
9
Here is an example of the use of the UP (faster) key:
Refill Discharge ID
(sec) (sec)
Key Press
---
1
2
3
10.0
9.5
9.0
8.5
5.0
5.5
6.0
6.5
103
104
105
106
With this method, the number of complete pump cycles per minute is fixed, within a range of 1
to 6; 4 CPM is the default value which appears at startup. Each time the up/down arrow keys
are pressed, the pump refill and discharge times are both automatically adjusted to maintain
the selected CPM value. Each adjustment increases or decreases the volume pumped per
cycle, and the per-minute flow rate is the volume per cycle X the CPM value.
For example, with a 4 CPM setting, 60 ml volume per cycle equates to 4 X 60 = 240 ml/min
flow rate. A single press of the Flow up arrow key could change the volume per cycle to 80 ml,
for example, resulting in a new, increased flow rate of 4 X 80 = 320 ml/min. And the MP10
assigns a unique identification value to each setting, the ID value, which can be directly set
during later sampling events.
"MP" displayed in the lower left corner of the display indicates MicroPurge mode. The default
CPM setting of 4 cycles per minute is a good starting point for wells with depths from 25-100 ft.
MicroPurge mode starts at a time setting of 10 seconds refill and 5 seconds discharge, close to
optimal for many wells. This startup settings corresponds to a 4 cycles per minute setting
(CPM4) and an ID setting of 103.
Using the CPM key will change the CPM setting on the controller. The range of CPM settings
is CPM1 through CPM6. CPM changes like this each time you hit the CPM key: 4 5 6 1 2 3
4 5, etc. The UP and DOWN keys change the flow rate directly, by altering the refill and dis-
charge times within a CPM setting.
Note: changes in settings that are entered while the controller is cycling are reflected on the
next cycle change (so a long refill time of 15 seconds will time out before a new refill time be-
comes valid).

Operation
10
Sample Collection The PAUSE key ( ) is used to freeze the controller action to allow the
user time to collect a sample or carry out other steps that might be difficult if the controller contin-
ued to automatically cycle and cause the pump to produce water. While the controller is cycling,
pressing the PAUSE key causes the controller to immediately enter the Hold state. Drive air is
vented from the pump (this is the pump refill cycle) and the pump fills and waits. Pressing the
PAUSE key a second time causes the controller to immediately enter the Sample state. Drive air
is directed to the pump causing the pump to discharge its volume of liquid. Bladder pumps typic-
ally hold 400-500 ml of liquid, so use of the Hold and Sample states allow the full volume of the
pump to be discharged into a sample container. Pressing PAUSE once again returns the MP50 to
its normal Automatic Cycling state. During Hold and Sample a HELD is displayed to remind you
that the controller is in a paused state. Figure 3 shows an example of the MP50 in MP mode, but
HELD in the Sample state.
I I
Figure 3 MP50 Held State (MP mode)
MicroPurge Basics Controller
MP Micro Purge
ID ID Time Set MN Manual Time Set LVL LevelShutoff
CYCLE
I I
MODE
CPM/Value Flow/Value Flow/Value
Hold/Sample
/Cycle
Start/Stop ID/MN/MP/
Battery
Mode CPM
ID
Time Refill
Discharge
HELD
103 10.0
MP CPM4 >05.0
DE
Each of the 165 possible ID settings corresponds to a unique ID that is associated with CPM, refill
and discharge time values. For typical usage, only the UP/DOWN arrow keys are required to set
flow, and the ID number is provided for easy, direct return to past settings. Appendix 1 lists all pos-
sible ID settings and the default refill and discharge time settings for each CPM. Appendix 1 also
shows how the refill and dis-charge time will change within a CPM setting as you press the UP or
DOWN keys.
Note: Pressing the Cycle key also freezes controller cycling. However, using the Cycle key rather
than the Pause key causes the startup screen to be displayed upon restart. Use of the Pause key
is recommended for typical operation.

Operation
Flow Throttle Use The flow throttle is used during sampling to regulate the pressure applied
to the pump. Turning the throttle clockwise increases the pressure and counterclockwise de-
creases the pressure. The pressure gauge shows the approximate pressure applied to the
pump and reads in units of Feet - H²O. This allows easy adjustment of the throttle giving press-
ures that will produce gentle, non-turbulent flow (normally 10-20 Feet - H²O deeper than pump
depth). For traditional, high volume purging pressure may be increased with the throttle to
maximize pump flow during well purging.
Use with the MP30 Automatic Drawdown Control The MP50 may optionally be used with the
MP30 MicroPurge Drawdown / Water Level Meter. See Figure 4 for an example of the MP50 in
MP mode with the controller in a level paused state enacted by an MP30 meter.
Figure 4 MP50 Level Paused State (MP mode)
11
MicroPurge Basics Controller
MP Micro Purge
ID ID Time Set MN Manual Time Set LVL LevelShutoff
CYCLE
I I
MODE
CPM/Value Flow/Value Flow/Value
Hold/Sample
/Cycle
Start/Stop ID/MN/MP/
Battery
Mode CPM
ID
Time Refill
Discharge
LVL
10.0
MP CPM4 >05.0
DE
Warning: in the HELD SAMPLE state the pump, tubing and hoses are all under pressure.
DO NOT attempt to disconnect or disassemble any part of the system when it is under pres-
sure. The system is under pressure if the pressure gauge shows a value greater than 0 and
the RED Discharge Cycle Indicator is showing.

Operation
Figure 5 MP50 MP30 Use
Figure 6 MP50 MP30 Use
MP10 MP30
Maximum Point
of Drawdown
Normal
Static
Level
MP50
12
Controller to pump
connection
Compressed gas source
connection
Connector for optional
MP30 Drawdown Control
Flow throttle
Discharge cycle
indicator
psi
0
THROTTLE
CONTROL PORT
DISCHARGE CYCLE
AIR IN
AIR OUT
MicroPurge Basics Controller
MP Micro Purge
ID ID Time Set MN Manual Time Set LVL LevelShutoff
CYCLE
I I
MODE
CPM/Value Flow/Value Flow/Value
Hold/Sample
/Cycle
Start/Stop ID/MN/MP/
Battery
Mode CPM
ID
Time Refill
Discharge
00.1
103 10.0
MP CPM4 >05.0
DE
DE
1-800-624-2026
micropurge.com
O
U
ED
asics
CONTROLLER
MP10
MicroPurge Mode Quick Guide
3 AA BATTERIES INSIDE
MODEL
MicroPurge Mode Quick Guide
1. Opening cover turns power ON. (Close to turn OFF.)
2. Select desired Cycles Per Minute (CPM) with the key
(default value is 4 CPM).
3. Turn throttle to set depth on gauge to 10-20 feet
deeper than the pump location in the well.
4. Press CYCLE to START pumping.
5. When water discharge begins, adjust throttle until
a slow, steady flowstream is achieved.
6. Press keys to set the desired purge flow.
7. Use key to directly control sample flow and pause.
II

Operation
The normal operating mode for using the MP30 with the MP50 is:
1. Use the MP30 in standard WLM mode to determine the static water level in the well
2. Decide what the maximum drawdown for that well is during sampling
3. Lower the probe to the maximum drawdown level
4. Switch the MP30 into Drawdown Control mode
5. Begin pumping with the MP50
13
The MP50 and MP30 are connected with a cable (see Figures 5 and 6). The MP30 is switched
into mode and the water level probe is lowered to the desired maximum drawdown level.
Limiting the maximum drawdown depth limits the differential head driving flow into the well and
the velocity of the water flowing into the well from the surrounding formation important in Micro-
Purge sampling. The MP50 and MP30 work together to automatically adjust the pump opera-
tion so as to maintain drawdown at the set level. When the water level drops below the probe,
the MP30 sends a signal to the MP50 to pause pumping. Both the MP50 and the MP30 give
visual signals (and the MP30 emits an audio signal) that pump operation has stopped because
of too much drawdown. Once the level recovers, the MP30 signals the MP50 to resume pump
operation. The MP50 resumes by starting in the refill leg of the pump cycle. "DRAWDOWN
CONTROL"
6. Observe the interactions between the two devices, if the MP30 is frequently pausing the
MP50, it may be appropriate to slow the flow down (using the DOWN key in MP mode) to
better match pump flow to well recharge.
When switched into mode, the MP30 has a flashing red light and an optional (can be switched
off by the user) audio alarm to indicate when the probe is in the dry state.A submerged probe
in all modes is indicated by a solid green light. When the MP50 is paused by the MP30 the MP
50 display indicates this as shown in Figure 4 "DRAWDOWN CONTROL"

Additional information on the MP30 is given in the MP30 O&M manual
Operation
ID Mode Figure 6 shows an example of the MP50 in ID time set mode. Once you've used the
MP50 in MP mode and found proper settings for your wells, subsequent sampling events are
speeded along by using the controller in ID mode. Once the controller is turned on, a single
press of the MODE key places the controller in ID time set mode (the default initial mode is MP
mode). This mode allows the user to enter a 3-digit ID, which then is translated into the correct
flow settings (CPM and refill / discharge time settings) for that well.
Figure 7 MP50 ID Set Mode
MicroPurge Basics Controller
MP Micro Purge
ID ID Time Set MN Manual Time Set LVL LevelShutoff
CYCLE
I I
MODE
CPM/Value Flow/Value Flow/Value
Hold/Sample
/Cycle
Start/Stop ID/MN/MP/
Battery
Mode CPM
ID
Time Refill
Discharge
00.1
103 10.0
MP CPM4 >05.0
DE
14
If the MP30 is signaling the MP50 too frequently, the operator can slow down the pump flow
rate by using the DOWN key (effectively increasing the pump refill time period). MP30 probe
position may also be varied to provide a buffer zone for your drawdown limit and gauge rate of
pumping effect on water level in the well.
If the selected maximum drawdown level is being reached even with the lowest desirable pump
flow rate more drawdown may be required to attain equilibration, or a passive sampling app-
roach may be required. In passive sampling, used where well recovery is extremely slow, sam-
ples are taken after just a few pump strokes sufficient to purge the pump and tubing volumes.

Operation
User Set Mode A final controller mode, User Set mode (MN on the display), is useful for man-
ually setting refill and discharge times on the controller as in traditional controllers (like previous
model QED pump controllers). An example of the MP50 in User Set mode is shown in Figure
8. User set mode is also used when the wells being sampled are at extreme depths or there
are other conditions where one of the 165 possible preset times of ID and MP modes will not
match your needs. MN mode is entered when the MODE key is pressed twice from the default
MP mode. As shown in Figure 8, the display indicates MN mode in the lower left corner and
CPM and ID are not displayed.
Figure 8 MP50 User Set Mode (MN mode)
MicroPurge Basics Controller
MP Micro Purge
ID ID Time Set MN Manual Time Set LVL LevelShutoff
CYCLE
I I
MODE
CPM/Value Flow/Value Flow/Value
Hold/Sample
/Cycle
Start/Stop ID/MN/MP/
Battery
Mode CPM
ID
Time Refill
Discharge
00.1
10.0
MN >05.0
DE
15
Note: changes in time settings that are entered while the controller is cycling are reflected on
the next cycle change (so a long refill time of 15 seconds will time out before a new refill time
becomes valid).
In this mode the CPM and UP, DOWN keys function differently. The CPM key becomes a key
used to scroll between the one's and the ten's digits of the ID. The UP and DOWN keys are
used to change the ID number (the MP50 has IDs that range from 1-165) up or down in value.
Sampling in ID mode is the same as explained, above, for MP mode.
Appendix 1 lists all possible ID settings and the default refill and discharge time settings for
each CPM. Appendix 1 also shows how the refill and discharge time will change within a CPM
setting as you press the UP or DOWN keys. As you change IDs you will see the CPM change
and the refill and discharge time setting change.

Operation
Note: changes in time settings that are entered while the controller is cycling are reflected on
the next cycle change (so a long refill time of 15 seconds will time out before a new refill time
becomes valid).
MP50 Battery - The MP50 features sophisticated power-supply circuitry that optimizes battery
life. A fresh set of AA batteries will provide more than 100 hours of controller operation at
normal operating temperatures. As ambient temperatures drop below 15-20˚F (-9˚C to -6˚C),
the ability of the alkaline batteries to deliver energy is affected. Continuous operation may be
difficult in extremely cold conditions. Once the batteries and MP50 warm, additional cycle cap-
acity will be regained from a set of batteries.
16
In User Set mode the CPM and UP, DOWN keys function differently than MP mode. The CPM
key becomes a key used to select the digits of the refill and discharge time settings found at
the rightmost positions on the display. The UP and DOWN keys are used to adjust the digit
value up or down. By selecting and adjusting digits up and down a user can quickly set any
time from 00.1 seconds to 99.9 seconds. Sampling in User Set mode is the same as explain-
ed, above, for MP mode.
The MP50 does not attempt to translate a user set time into a corresponding ID or CPM. Also,
any settings you have entered in MP or ID modes are lost once you press the MODE key to
enter MN mode.
Replace alkaline batteries by removing the 4 thumbscrews located on the battery cover and
inserting 3 fresh cells. The MP50 battery holder includes space for 3 spare AA cells so you
should never be without power in the field. Properly dispose of the spent alkaline cells.
Note: If you are storing the MP50 for more than 3 months, remove the AA batteries to prevent
leakage. The MP50 power supply is automatically shut off by closing the lid. Make sure the lid
is closed during storage.