Acorn MERIDIAN 3791-RO Instruction manual

ACORN ENGINEERING FIELD SERVICE
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INSTALLATION, OPERATIONS & MAINTENANCE MANUAL
Part #: 9927-141-001
Please visit www.acorneng.com
for most current specifications.
A C O R N E N G I N E E R I N G C O M P A N Y
P. O . B O X 3 5 2 7 • C I T Y O F I N D U S T R Y, C A 91 7 4 4 U . S . A .
T O L L F R E E 8 0 0 - 4 8 8 - 8 9 9 9 : : L O C A L 6 2 6 - 3 3 6 - 4 5 6 1
FA X 6 2 6 - 9 6 1 - 2 2 0 0 : : w w w. a c o r n e n g . c o m
A C O R N E N G I N E E R I N G C O M P A N Y
P. O . B O X 3 5 2 7 • C I T Y O F I N D U S T R Y, C A 91 7 4 4 U . S . A .
T O L L F R E E 8 0 0 - 4 8 8 - 8 9 9 9 : : L O C A L 6 2 6 - 3 3 6 - 4 5 6 1
FA X 6 2 6 - 9 6 1 - 2 2 0 0 : : w w w. a c o r n e n g . c o m
Cleaning and Maintenance................................22
Prior to Installation.......................................2
TABLE OF CONTENTS
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-16
Piezo Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-19
Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-21
Components & Repair Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-27
Rough-Ins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 - 7
Accessibility Overview ....................................3
Dimensional Data........................................4
Warranty Information ....................................28
REQUIRED ITEMS FOR INSTALLATION - NOT SUPPLIED
®
MERIDIAN
MODEL
3791-RO
®
CORTERRA
ADA-COMPLIANT
KURVE SINGLE BASIN
MODEL# 3791-RO-1-SO-DV
RIGHT SIDE OFF-SET
CONFIGURATION
?Carpenters Level
?7/16" Hex Wrench
?Chalk Line
?1/4” Slotted Tip Screwdriver For Metering
Adjustment
?Hammer
?1/2" NPS Supply Angle Stops And 1/2" NPS
Supply Flex Hose(s)
?Driver For 1/4” Shank Bit - For Center Reject Bit
?Teflon Tape
?Plumbers Putty
?Fixture Wall Anchors and Anchoring Hardware
(and Appropriate Tools) - For 3/8" Punching
(13 Count)
®
MERIDIAN 3791-RO
Date: 03/07/19

ACORN ENGINEERING FIELD SERVICE
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INSTALLATION, OPERATIONS & MAINTENANCE MANUAL
®
MERIDIAN 3791-RO
Part #: 9927-141-001
Please visit www.acorneng.com
for most current specifications.
Page 2 of 28
Important: Some options may slightly alter installation. To ensure proper installation
review the manual thoroughly and verify rough-ins before beginning any work. File this
manual with the owner or maintenance personnel upon completion of installation.
ANSI, UFAS or ADA compliance is subject to the interpretation and requirements of the
local code authority and is the responsibility of the installer for verification.
Single Temp Valve Assembly: Recommended working water pressure is 30 psi (2.07
bars) minimum to 100 psi (6.89 bars) maximum. Maximum temperature is 130°F
(54.4°C). Maximum outlet temperature is recommended is 105°F (40.6°C). Valve
assembly must be drained prior to being subjected to freezing temperatures. A
checkstop is provided with this valve assembly.
Teflon tape is recommended on all threaded waste and supply connections to reduce the
possibility of leaks.
NOTE: Receptacle(s) must be wired to a GFCI protected circuit. Fixture must be earth
grounded per N.E.C. (National Electrical Code).
Provide 110-120VAC/60Hz/3A (MAX) electrical receptacle for factory supplied
120VAC/9VDC, 100mA plug-in transformer.
T/P Mixing Valve Assembly: Recommended working water pressure is 30 psi (2.07 bars)
minimum to 125 psi (8.62 bars) maximum. Maximum hot water temperature is 180°F
(82°C). Temperature adjustment range is 85-115°F (29-46°C). Valve assembly must be
drained prior to being subjected to freezing temperatures. The valve assembly has
checks integral to the inlets however, angle stops are to be provided by the installer.
Prior to installation, supply lines must be flushed of all foreign material such as pipe
dope, chips, or solder. Debris or foreign material in water supply may damage valve.
Industry standard wall backing, for wall hung fixtures, is required. Installer provided wall
anchors and wall anchoring hardware must be appropriate for wall construction, and
have a minimum pull-out rating of 1000 lbs. (453.6 kg).
Date: 03/07/19

ACORN ENGINEERING FIELD SERVICE
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INSTALLATION, OPERATIONS & MAINTENANCE MANUAL
®
MERIDIAN 3791-RO
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Page 3 of 28
ACCESSIBILITY OVERVIEW
Part #: 9927-141-001
ADA ages
6 thru 12
ADA
Adult
34" RIM
MAX.
4"
9"
121
2"
21"
21"
183
4"
27"
MIN.
21"
121
2"
4"
31" RIM
MAX.
24"
MIN.
21"
153
4"
21"
121
2"
4"
33" RIM
MAX.
29"
MIN.
21"
173
4"
9"
9"
OBC
Date: 03/07/19

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INSTALLATION, OPERATIONS & MAINTENANCE MANUAL
®
MERIDIAN 3791-RO
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Page 4 of 28
DIMENSIONAL DATA
15"
53
4"
4"
191
4"
11"
21"
24"
53
8"5
8"
Part #: 9927-141-001 Date: 03/07/19

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INSTALLATION, OPERATIONS & MAINTENANCE MANUAL
®
MERIDIAN 3791-RO
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Page 5 of 28
Part #: 9927-141-001
ROUGH-IN DIMENSIONS - ADA (Adult)
E
D
C
B
A
-Supply Stub-Outs with Stops for Valve 1/2" NPT Hot & Cold Supply Inlets.
-Frame "V" Notch.
-120VAC, 60 Hz, 3A (Max.) GFCI Protected, Electrical Receptacle.
-Waste Outlet for 1-1/2" O.D. P-Trap.
- 3/8" Diameter Mounting Holes, For Anchoring Points, 13 Places.
34"
DECK
HEIGHT
25"
211
2"235
8"
21
2"
297
8"
327
8"
81
4"
TYP.
83
4"
8"
51
2"
TYP. 31
2"
TYP.
13
4"
3"
21
2"
HC
E
A
C
B
D
Date: 03/07/19

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INSTALLATION, OPERATIONS & MAINTENANCE MANUAL
®
MERIDIAN 3791-RO
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Page 6 of 28
ROUGH-IN DIMENSIONS -ADA
AGES 6 THRU 12 YEARS
E
D
C
B
A
Part #: 9927-141-001
-Supply Stub-Outs with Stops for Valve 1/2" NPT Hot & Cold Supply Inlets.
- 3/8" Diameter Mounting Holes, For Anchoring Points, 13 Places.
-Waste Outlet for 1-1/2" O.D. P-Trap.
-Frame "V" Notch.
-120VAC, 60 Hz, 3A (Max.) GFCI Protected, Electrical Receptacle.
31"
DECK
HEIGHT
22"
181
2"205
8"
21
2"
267
8"
297
8"
81
4"
TYP.
83
4"
8"
51
2"
TYP. 31
2"
TYP.
13
4"
3"
21
2"
HC
E
A
C
B
D
Date: 03/07/19

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INSTALLATION, OPERATIONS & MAINTENANCE MANUAL
®
MERIDIAN 3791-RO
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Page 7 of 28
ROUGH-IN DIMENSIONS -OBC
ONTARIO BUILDING CODE
E
D
C
B
A
Part #: 9927-141-001
-Supply Stub-Outs with Stops for Valve 1/2" NPT Hot & Cold Supply Inlets.
-Waste Outlet for 1-1/2" O.D. P-Trap.
-Frame "V" Notch.
- 3/8" Diameter Mounting Holes, For Anchoring Points, 13 Places.
-120VAC, 60 Hz, 3A (Max.) GFCI Protected, Electrical Receptacle.
33"
DECK
HEIGHT
24"
201
2"225
8"
21
2"
287
8"
317
8"
81
4"
TYP.
83
4"
8"
51
2"
TYP. 31
2"
TYP.
13
4"
3"
21
2"
HC
E
A
C
B
D
Date: 03/07/19

ACORN ENGINEERING FIELD SERVICE
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INSTALLATION, OPERATIONS & MAINTENANCE MANUAL
®
MERIDIAN 3791-RO
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Part #: 9927-141-001
FIXTURE ANCHORING
Disassemble access panels and deck assembly
1from frame. Anchor frame to wall using 3/8" mounting
hardware by others.
-See DETAIL A. Place deck assembly on frame making
2sure angle engages behind frame joggle.
-See DETAIL C. Assemble deck support flanges to
outside of frame using 1/4-20 x 1" long hex bolts, 1/4"
lock washers and 1/4" flat washers provided.
-See DETAIL B. Assemble underside of bowls to frame
with 1/4-20 x 1/2" long hex bolts and 1/4-20 x 2-1/2"
long threaded studs, 1/4" lock washers, fender
washers and 1/4-20 hex nuts provided.
DETAIL
B
DETAIL
C
DETAIL
A
ANGLE
FRAME
JOGGLE
DECK SUPPORT
FLANGES
Page 8 of 28 Date: 03/07/19

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®
MERIDIAN 3791-RO
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1
2
3
4
4
3
5
Assemble waste piping using teflon tape on all threaded
4connections and make up waste connections to 1-1/2" P-trap.
Install grid strainer and close elbow to bowl
3using plumber's putty.
HINT: Teflon tape is recommended on all threaded waste and
supply connections.
NOTE: Waste assembly may require field cutting and fitting by the
installer.
À Grid Strainer w/ 1-1/2" -16
UNE Threads
Á Rubber Gasket
à 1-1/2" -16 UNI Rough Chrome
Brass Jam Nut
Ä 1-1/2"-16 x 1-1/4" UNI Close Ell
with 3/8" NPT Clean-Out Plug
 Flat Fiber Washer
51
2"
REF.
43
4"
REF.
31
2"
REF. 13
4"
REF.
Page 9 of 28
Part #: 9927-141-001 Date: 03/07/19

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INSTALLATION, OPERATIONS & MAINTENANCE MANUAL
®
MERIDIAN 3791-RO
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MX-TP VALVE (-H HAND OPERATED SHOWN)
-ST SINGLE TEMPERATURE VALVE (-H HAND OPERATED SHOWN)
!IMPORTANT
for -ST Single Temperature valves, flush supply line. Connect installer
Bprovided 1/2" NPS flex hose to valve.
Before making up the supply
connections, the supply
lines must be flushed of all
foreign material such as
pipe dope, pipe chips,
solder, sand, etc.
for MX-TP Valve (Hot & Cold), Flush Supply lines.
AConnect installer provided 1/2" NPS flex hoses to
valve.
VALVE ASSEMBLY
VALVE ASSEMBLY
Page 10 of 28
Part #: 9927-141-001 Date: 03/07/19

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®
MERIDIAN 3791-RO
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Part #: 9927-141-001 Page 11 of 28
5) Turn on fixture and allow water to flow for 2
minutes. Measure water temperature at
outlet. If water is not at desired temperature,
adjust as necessary.
1) Locate suitable place for mounting the valve
assembly. Valve assembly should be
accessible for service and adjustment and
as close to the point-of-use as possible.
Wall anchors and anchoring hardware, for
Ø3/8” mounting holes, provided by installer.
NOTE: Installation should be in accordance with
accepted plumbing practices.
2) Connect hot and cold water to supply
valve using 1/2” NPTE connections.
3) Connect outlet of tempering valve to
spout(s) using 1/4” O.D. tube connections
provided.
4) Turn on hot and cold water supplies. If any
leaks are observed, hand tighten
connections as necessary to stop leaks
before proceeding.
3) Turn temperature stem counter-clockwise
for hotter or clockwise for colder outlet
temperature.
2) Turn on fixture and run water for at least 2
minutes. Allow supply temperature to
stabilize.
1) Loosen locknut.
4) Tighten locknut to prevent accidental or
unauthorized temperature adjustment.
5) Re-check outlet temperature.
Temperature Adjustment:
Valve Assembly Installation:
VALVE INSTALLATION & ADJUSTMENT
!IMPORTANT
Flush supply lines of all foreign material such
as pipe dope, pipe chips, solder, sand etc.
before making up supply connections.
HINT: Angle stops are recommended
and is the responsibility of the installer.
LOCKNUT
WARMER
TEMPERATURE
STEM
Date: 03/07/19

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-SO Sensor Operation
Range Adjustment
1. Make sure power supply is disconnected from
sensor and make short circuit on red wires.
See DETAIL A.
4. Move hand to desired sensing distance.
See DETAIL B.
3. Move hand in front of sensor to distance of 2” to 4”
within 5 seconds and wait until red light flashes
quickly.
2. Connect power supply to sensor. Red light should
be flashing.
5. Hold hand at desired sensing distance until red light
stops flashing and solenoid activates.
See DETAIL C.
DETAIL A
DETAIL B
DETAIL C
Transformer must
be plugged into a
GFI protected
circuit. Fixture must
be earth grounded
per N.E.C. or
applicable codes.
Jumper
By Others
-SO Sensor Operation or -PPZ Programmable Piezo Pushbutton
SENSOR OPERATION & CONNECTIONS
Part #: 9927-141-001 Page 12 of 28 Date: 03/07/19
-SO SENSOR
-PPZ PUSHBUTTON
RED BLUE
RED
BLUE
TRANSFORMER
SOLENOID VALVE

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To service or install batteries
remove access panel by
removing (4) 10-32 x 3/4"
screws from front of fixture
using allen head bit provided
(socket & driver by others).
Replace access panel when
finished.
-SO-BAT
Sensor Operation Battery Powered
SENSOR OPERATION & CONNECTIONS -BATTERY OP
Acorn does not provide batteries for -BAT units.
Each station requires (6) AA batteries.
Part #: 9927-141-001 Page 13 of 28 Date: 03/07/19
-SO SENSOR
-PPZ PUSHBUTTON
RED BLUE
RED
BLUE
TRANSFORMER
SOLENOID VALVE

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Ferrule Nut
1/4"
Min.
Ferrule
Nut
-H Hand Operated
1/8" O.D. AIR TUBE
1/4" O.D. WATER LINE
Leave a minimum 1/4” of polyethylene tubing
through the Ferrule Nut on the pushbutton
assembly. This is necessary to ensure proper
tubing connection.
Timing Screw
To adjust timing,
turn timing screw.
HAND OPERATION & CONNECTIONS
Turn timing screw clockwise to
increase timing.
Do not over tighten
ferrule nuts.
Part #: 9927-141-001 Page 14 of 28 Date: 03/07/19

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ACCESS PANEL INSTALLATION
Part #: 9927-141-001
Install front and side access panels using 10-32 x 3/4" center reject hex head screws provided.
Page 15 of 28 Date: 03/07/19

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-DV SOAP OPTION RETRO-FIT & INSTALLATION
Remove Access Plug Install soap dispenser
®
MERIDIAN 3791-RO
Remove Corterra Plug Install soap filler
NOTE: Soap Tank Capacity = 0.5 Gallons
Some soaps contain corrosive additives that can cause rust in soap dispensers.
Acorn Engineering Company recommends user/ maintenance personnel review
MSDS reports of soap and possible corrosive additives noted.
Do not exceed the capacity of the soap tank (0.5 Gallons). Overfilling may result in spilling and
pooling of soap solution within the sprayhead enclosure and outside the soap tank.
!WARNING
Remove Corterra plug from
2top cover and soap access
plug from bottom of
sprayhead enclosure.
Remove top cover from
1unit. To remove cover, use
Allen head bit provided and
unscrew 10-32 x 3/4" long
vandal resistant fasteners
shown. Hex bit driver is
installer provided.
Position and install soap
3tank in sprayhead
enclosure as shown and
install soap dispenser by
aligning dispenser with
drain adapter and fixing
with set screws as shown
Fill soap tank by removing
5filler cap and pouring soap
directly into tank. Do NOT
overfill.
Install soap filler assembly
4to top cover and replace.
Install Soap Tank
Sprayhead Enclosure
Page 16 of 28
Part #: 9927-141-001 Date: 03/07/19

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Programable Piezo Pushbutton
Programming Instructions (Flow Time Adjustment)
As soon as the cable is reconnected the LED will start flashing, it will flash 4 times, then stays on for 3 seconds.
During the 3 second period, push the piezo button once, the LED will go out, now you are in the 1 sec timing mode
and each time the button is pushed the LED will flash, adding 1 sec to the total timing cycle.
— Each timing mode (1 sec, 5 sec or 20 sec timing mode) can be sequenced up to 100 times, that is
the number of times, the button can be pushed, to increase the total timing cycle in each timing mode.
In order to start the programming the piezo pushbutton, the button must be powered down. Disconnect the red power
cable and wait 20 seconds, then reconnect the red power cable.
To move on to the 5 sec timing mode, pause and wait for the LED to flash 2 times, now you are in the 5 sec timing
mode. Each time the button is pushed the LED will flash, adding 5 sec to the total timing cycle.
— When a timing mode is not required then do not push the button and wait for the next timing mode.
To move on to the 20 sec timing mode, pause and wait for the LED to flash 3 times, now you are in the 20 sec timing
mode and each time the button is pushed the LED will flash, adding 20 sec to the total timing cycle. After programing
is complete, pause and wait for the LED to flash 4 times and then 5 times, which completes the programming.
THE TIME SETTINGS PROGRAM USES 3 DIFFERENT TIMING MODES:
— 1 second timing mode: Each push of the button adds 1 second to the total timing cycle.
— 5 second timing mode: Each push of the button adds 5 seconds to the total timing cycle.
— 20 second timing mode: Each push of the button adds 20 seconds to the total timing cycle.
To program the piezo pushbutton, you will need to be able to see the back of the piezo pushbutton.
Prevision must be made to access the back of the piezo pushbutton. There is an LED on the back of the piezo
pushbutton under a layer of transparent epoxy, used as a programming indicator light.
NOTE: This programming procedure moves along rapidly, there is
only about 2 or 3 seconds between programming operations.
The Button is factory set an 8 sec. timing cycle, if an 8 sec. cycle is adequate, then no programming adjustment
is required.
NOTE: Read the entire document before
trying to program the piezo pushbutton.
Page 17 of 28
®
MERIDIAN 3791-RO
Part #: 9927-141-001 Date: 03/07/19

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Determine the
number of seconds
per timing cycle
1 Push = 1 Second
x 1 = sec
Fill in all the
Boxes below
1 Push = 5 Seconds
x 5 = sec
ADD
1 Push = 20 Seconds
x 20 = sec
ADD
Total timing cycle equals
seconds
EQUALS
Ÿ Reconnect power.
Ÿ While the LED is steady on, push button.
Ÿ LED turns off.
Ÿ Pause and wait for the LED to flash 3 times.
Ÿ You are in the 20 sec timing mode, immediately push the button, 1
push equals 20 sec added to the total timing cycle.
Ÿ You are in the 1 sec timing mode, immediately push the button, 1 push
equals 1 sec added to the total timing cycle.
Ÿ LED flashes, then stay on.
PROGRAMING STEPS:
— Power down piezo button for 10 seconds.
Ÿ Pause and wait for the LED to flash 2 times.
Ÿ You are in the 5 sec timing mode, immediately push the button, 1 push
equals 5 sec added to the total timing cycle.
Programming Instructions (Flow Time Adjustment)
Programmable Piezo Pushbutton
WORKSHEET
(FILL IN ALL BOXES, WHICH WILL SIMPLIFY THE PROGRAMMING PROCEDURE)
Page 18 of 28
®
MERIDIAN 3791-RO
Part #: 9927-141-001 Date: 03/07/19

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BLACK RED
BLACK SOLENOID
CABLE
RED POWER
CABLE
PROGRAMMING INDICATOR
LED LIGHT
TRANSPARENT
EPOXY FILLING
PIEZO
PUSHBUTTON
Page 19 of 28
®
MERIDIAN 3791-RO
Part #: 9927-141-001 Date: 03/07/19

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TROUBLE SHOOTING FOR 9 VOLT DC SENSOR OPERATED VALVES
Normal Valve Function: 9 Volt DC sensor operated valve has flow time of 90 seconds maximum.
To reactivate, the user must move out of and return to the sensing area.
CONDITION: WATER DOES NOT FLOW
Indicators Probable Cause Solution
Sensor flashes continuously
every 2 seconds when
hands are within range.
Low battery warning Replace battery
Circuit breaker tripped. Reset circuit breaker
Replace battery
Defective 9V DC transformer
Transformer polarity crossed Replace transformer (sensor may be
damaged and need replacement).
Unit is in “Security Mode” after
90 seconds of constant detection.
Remove sources of detection and
wait 30 seconds before checking.
Range is too short. Increase range.
Range is too long. Decrease range and wait 30 seconds.
Sensor is picking up a highly
reflective surface. Eliminate cause of reflection and wait
30 seconds before checking.
Sensor does not flash
when the user’s hands
are within range.
Defective sensor. Replace sensor.
Stops or water main closed.
Bad sensor to solenoid connection.
Debris or scale in
solenoid assembly.
Remove solenoid, pull out plunger
and spring, and clean with scale
remover solution or pressurized air.
Debris or scale in diaphragm. Remove diaphragm and clean
Sensor flashes once
when user’s hands are
within range.
Remove strainer and clean.
CONDITION: FALSE TRIGGERING;
WATER FLOWS CONTINUOUSLY
Indicators Probable Cause Solution
Remove diaphragm and clean. Sensor flashes when user’s
hands are within range. Diaphragm is defective or torn.
Sensor is dirty or covered. Clean or uncover sensor and
wait 30 seconds.
Decrease range and wait 30 seconds.
Sensor does not flash when
users hands are within range. Range too long or highly
reflective surface, sunlight, bright
lights etc. are triggering sensor. Eliminate cause of reflection or
correct lighting problem.
CONDITION: WATER FLOWS
CONTINUOUSLY BUT STOPS
WHEN HANDS ARE WITHIN RANGE
Indicators Probable Cause Solution
Water runs continuously when
sensor not activated. Sensor
flashes when hands are within
range and water shuts off.
Solenoid polarity crossed. Disconnect solenoid and
reverse polarity.
Battery completely used up.
Replace transformer.
Open stops or water main.
Ensure wires make proper contact.
Debris or scale in strainer.
Replace diaphragm.
Debris or scale in diaphragm
Part #: 9927-141-001 Page 20 of 28 Date: 03/07/19