SPX MARLEY LLC User manual

LLC water level control
INSTALLATION - OPERATION - MAINTENANCE
Z0628617_B ISSUED 07/2018 READ AND UNDERSTAND THIS MANUAL PRIOR TO OPERATING OR SERVICING THIS PRODUCT.
user manual

2
contents
Quick Start Guide.......................................................................................................4
Description ...................................................................................................................5
Operation......................................................................................................................6
Water Makeup Function............................................................................................7
HAND-OFF-AUTO Switch........................................................................................7
Internal Components..................................................................................................8
Electrode Probe Assembly .......................................................................................9
Operation Sequence Illustrations............................................................................9
Water Makeup Control Sequence.......................................................................10
High-Level Alarm Sequence..................................................................................11
High-Level Cutoff Sequence.................................................................................11
Low-Level Alarm Sequence...................................................................................12
Low-Level Cutoff Sequence..................................................................................12
Troupleshooting........................................................................................................13
Electrode Probe Part Numbers ............................................................................14
Relay Circuit Card Part Numbers.........................................................................15
Part Numbers............................................................................................................15
Wiring Diagrams.......................................................................................................16
This manual contains vital information for the proper installation
and operation of the LLC controls. Carefully read the manual before
installation or operation and follow all instructions. Save this manual
for future reference.
Note
Indicates presence of a hazard which can cause severe personal
injury, death or substantial property damage if ignored.
Indicates presence of a hazard which will or can cause personal
injury or property damage if ignored.
Indicates special instructions on installation, operation or mainte-
nance which are important but not related to personal injury hazards.
Warning
Caution
Note
The following defined terms are used throughout this manual to
bring attention to the presence of hazards of various risk levels, or
to important information concerning the life of the product.

3
introduction
These instructions are intended to assure that field connections are completed
properly and the control system operates for the maximum time possible. Since
product warranty may depend on your actions, please read these instructions
thoroughly prior to operation.
If you have questions about the operation and/or maintenance of this control
system and you do not find the answers in this manual, please contact your
Marley sales representative.
Hazard of electrical shock or burn. Be sure to turn off power to the
panel before servicing. If working on equipment out of site of panel
disconnect, lockout using standard lockout procedure.
Safety First
The Marley control system uses UL listed components installed in accordance
with the National Electric Code. The location of the cooling tower and field
installation of the control system can affect the safety of those responsible
for installing, operating or maintaining the tower and controls. However,
since SPX Cooling Technologies does not control the tower location, or field
installation, we cannot be responsible for addressing safety issues that are
affected by these items.
The following safety issues should be addressed by those responsible
for installation, maintenance or repair of the tower and controls:
• Access to and from the control panel (including the customer supplied
main disconnect/branch circuit protection.)
• Proper grounding of electrical control circuits.
• Sizing and protection of branch circuits feeding the control panel.
• Qualification of persons who will install, maintain and service the electri-
cal equipment.
These are only some of the safety issues that may arise in the design and
installation process. Marley strongly recommends that you consult a safety
engineer to be sure that all safety considerations have been addressed.
Other safety issues are addressed in literature supplied with your tower. You
should closely review the literature prior to installing, maintaining or repairing
your tower.
Warning
Warning

4
quick start guide
Connect incoming power here.
Panel requires 120VAC 1 phase,
6 amp power with ground.
If a makeup solenoid circuit is
provided, connect the solenoid
wires here at points 4A and 2A.
This circuit provides 120 VAC
power for the solenoid.
Connect alarm and/or cutoff
control wiring to the grey terminal
points.
Connect water level probe wiring
to the blue terminals. The probes
are generally located in the
cold water basin of the cooling
tower.
To avoid water getting into the
control panel, all conduit entries
should be into the bottom of the
enclosure.
Note: If the control panel is furnished with a water makeup selector switch
located on the right-hand side of the enclosure:
HAND: position: Solenoid will energize. OFF: position: Solenoid is de-energized
AUTO: Solenoid will operate depending on water level in relation to water probe height.

5
description
The Liquid Level Control systems are used to accomplish
five different functions:
• Water Makeup • High Water Alarm
• Low Water Alarm • High Water Cutoff
• Low Water Cutoff
The most common application of a water level control
system is water makeup. The system regulates the amount
of water in the tower basin and keeps it within normal
operating levels. This makeup system is used to control
a remotely installed water solenoid valve. When the water
level drops below a prescribed, preset level, the solenoid
valve is energized by the control system to fill the basin
to its proper level.
LLC
Control Panel
Probe
System
30'-0 Lead
High and low cut-off dry contacts
High and low alarm dry contacts
MU powered with 120V Solenoid
Pump
Pump
BMS
Stilling
Chamber
Basin Floor
6amp 120/1/60
Utility Supply
Junction Box
by others if required
Extension
if required
Display
SYSTEM DIAGRAM
LLC Components Optional Field Components—by others
High and low water alarms can be utilized to give warn-
ings associated with abnormal operating water levels. To
provide indication of these types of alerts, the control sys-
tem provides dry contacts to interface with various digital
control systems or can be connected to user supplied alarm
indicators to signal when corrective action is required.
Low-water cutoffs are commonly used to protect pumps
from operating without sufficient water. When used in
unattended operating environments, the low-water cutoff
is configured to shut the pump off, thus preventing costly
repairs. Dry contacts can be wired directly in series with
pilot duty controls or to digital control systems to initiate
the shutdown of protected equipment during low-water
situations.

6
operation
Operation
The LLC water level control system consists of special purpose liquid sensing
relays on one or more individual circuit cards connected to a probe assembly
located in the cold-water basin. Each circuit card contains one relay and external
signaling is provided by each of these special purpose cards. The individual
relay provides a “Form C” normally open and normally closed dry contact. The
circuit card activates the relay using “through the water” continuity by way of
the senor probes located in the cold-water basin of the cooling tower.
Utilizing water’s ability to conduct electricity, a circuit path can be established
between one probe tip and the other. Current conducts through the water
across probes of dissimilar length. One common or reference probe is present
in all systems and is shared by all functions of the system. This probe can be
identified by its length. It is the longest probe in the system and extends the
deepest into the basin. The current path is routed between all other probe tips
and this one “common”. When the water level reaches the shorter probe, the
circuit is completed and the relay responds, opening or closing relay contacts
corresponding to a fixed level. For low-level control, the ground reference
probe and a slightly shorter probe provide the circuit. When the water level
drops below this tip, the continuity between this probe and the reference
probe is interrupted and the relay contacts transfer. The distance from the tip
of the low probe to the floor of the basin determines the minimum water level
that is allowed before an alarm is produced or pump operation is interrupted.
The number of additional probes is determined by the individual application.
As an example, in a “water makeup” system there are three probes. One
reference and two standard or short-tipped probes. The tip of the reference
probe is normally positioned slightly above the basin floor with the additional
probe tips positioned at different heights dictated by their specific function.
The Makeup system would have one probe at a height to begin or start filling
the basin and another positioned higher to complete or stop filling. A probe
for a High Alarm or High Cutoff would be positioned at a level to activate
when the basin water exceeds its normal operating level and logically a Low
Alarm or Low Cutoff would be positioned to detect a low water level nearer
the bottom of the basin. Again, signaling is achieved in two ways. High Level
and Makeup cards react when the water provides a completed circuit or
continuity between its sensor and the reference probe. The second type of
signal is for Low Level detection. The Low Level cards react when the water
is not present and opens the circuit or disrupts the current flow between its
probe and the reference.

7
operation
A water level control system can be configured to meet various combination
requirements. Since one individual circuit card is responsible for each func-
tion, the size and circuitry varies in proportion to the number of operations
desired. For example, a water level makeup control will require a control panel
with one circuit relay card and three probes. A system configured for water
makeup that includes a high alarm and a low alarm, will require three circuit
cards and five probes—one circuit card for the water makeup option, one for
high operation and one for low.
Water Makeup Function
A system is designed for alarms and/or cutoff indication only would not be
equipped with the water makeup function.
The circuitry for water makeup in the LLC control panel provides an indepen-
dent circuit breaker for direct connection to a 110-120VAC water solenoid
valve. This added feature allows customer installation without having to
provide an additional power circuit to energize the solenoid. The solenoid is
connected to terminals 2A and 4A as represented on the control’s specific
wiring diagram.
Purpose and Function of the HAND-OFF-AUTO Switch
Located on the right side of the control’s enclo-
sure is a HAND-OFF-AUTO switch. This switch
is used primarily at cooling tower startup and in
maintenance procedures where the tower basin
is empty or has been drained. When the tower’s
basin needs to be manually filled, the switch is
placed in the HAND position. This selection
bypasses the probe assembly’s feedback and
directly energizes the solenoid valve connected
to the water supply. Once the cooling tower basin
is filled, the switch is placed in the AUTO position to allow the adjusted probe
assembly to monitor and sustain the proper operating level. Placing the switch
in the OFF position completely interrupts any monitoring or fill action normally
provided by the LLC control panel. Normal tower operation depends upon the
HAND-OFF-AUTO switch being positioned in the AUTO mode at all times.

8
Internal Components of the LLC Control Panel
LLC control panels are built to UL and CUL standards and are designed to
provide the numerous configurations needed for cooling tower applications.
All LLC control panels include a main circuit breaker with an additional circuit
breaker and a HAND-OFF-AUTO switch provided when the system includes
a water makeup circuit. The additional circuit breaker provides an exclusive
control circuit for a 120VAC water solenoid valve. High and low circuit relay
cards and the appropriate terminal connections comprise the rest of the
components necessary for the specific configuration. The raised terminal strip
provides easier access to make the necessary connections of the water probe
assembly and customer interface.
Inside view of an LLC Control Panel with Makeup,
High Alarm, and Low Alarm.
operation

9
operation
Stainless Steel Electrode Probe Assembly
The electrode probe tips are stainless steel suspended from a noncorrosive
PVC enclosure box with 30 feet of wire for each probe. A galvanized or stain-
less steel stilling chamber is installed over the probes to calm the water for
accurate readings.
Illustrations Describing Operation Sequence
The next three pages are simplified illustrations representing the sequence of
operation for each type of circuit card:
Page 10 – Makeup
Page 11 – High Alarm – High Cutoff
Page 12 – Low Alarm – Low Cutoff
Each relay circuit card has two green indicator lights.
The ON light indicates the card is powered and ready
to function. The ENERGIZED light indicates when
the probe system is functioning and should be used
when troubleshooting.

10
operation
REFERENCE
PROBE
13
14
15
MAKE-UP
ON
PROBE
MAKE-UP
OFF
PROBE
Water
Level
CIRCUIT CARD
with RELAY
SOLENOID
VALVE
DE-ENERIZED
CONTROL PANEL
Power OFF
Relay
Contact
Open
4A
2
Valve
Closed
Water Level
Dropping
Water Level
Drops Below
MAKEUP
ON Probe
120VAC
REFERENCE
PROBE
13
14
15
MAKE-UP
ON
PROBE
MAKE-UP
OFF
PROBE
CIRCUIT CARD
with RELAY
SOLENOID
VALVE
SOLENOID
VALVE
ENERIZED
CONTROL PANEL
Power ON
Relay
Contact
Closed
4A
2
Valve
Open
120VAC
Water
Level
Rising
REFERENCE
PROBE
13
14
15
MAKE-UP
ON
PROBE
MAKE-UP
OFF
PROBE
CIRCUIT CARD
with RELAY
ENERIZED
CONTROL PANEL
Power ON
Relay
Contact
Closed
4A
2
Valve
Open
120VAC
Water
Level
Rising
REFERENCE
PROBE
13
14
15
MAKE-UP
ON
PROBE
MAKE-UP
OFF
PROBE
CIRCUIT CARD
with RELAY
SOLENOID
VALVE
ENERIZED
CONTROL PANEL
Power ON
Relay
Contact
Open
4A
2
Valve
Closed
120VAC
Water Level
Rises
To MAKEUP
OFF Probe
REFERENCE
PROBE
13
14
15
MAKE-UP
ON
PROBE
MAKE-UP
OFF
PROBE
CIRCUIT CARD
with RELAY
SOLENOID
VALVE
SOLENOID
VALVE
ENERIZED
CONTROL PANEL
Power ON
Relay
Contact
Open
4A
2
Valve
Closed
120VAC
REFERENCE
PROBE
13
14
15
MAKE-UP
ON
PROBE
MAKE-UP
OFF
PROBE
CIRCUIT CARD
with RELAY
ENERIZED
CONTROL PANEL
Power ON
Relay
Contact
Closed
4A
2
Valve
Open
120VAC
1.
2.
3.
4.
5.
6.
ENERGIZED ENERGIZED
ENERGIZED
Water Makeup Control – Sequence of Operation – B Card
Selector Switch in AUTO Position

11
REFERENCE
PROBE
13
16
HIGH
ALARM
PROBE
Water
Level
CIRCUIT CARD
with RELAY
CUSTOMER
CONNECTION
DE-ENERIZED
CONTROL PANEL
Power OFF
Relay
Contact
Closed
6
5
CIRCUIT CARD
with RELAY
ENERIZED
CONTROL PANEL
Power ON
Relay
Contact
Open
Water
Level
Rising
ENERIZED
CONTROL PANEL
Power ON
Relay
Contact
Closed
High
Alarm
Condition
1.
2.
3.
REFERENCE
PROBE
13
16
HIGH
ALARM
PROBE
CIRCUIT CARD
with RELAY
REFERENCE
PROBE
13
16
HIGH
ALARM
PROBE
REFERENCE
PROBE
13
17
HIGH
CUTOFF
PROBE
Water
Level
CIRCUIT CARD
with RELAY
DE-ENERIZED
CONTROL PANEL
Power OFF
Relay
Contact
Open
CIRCUIT CARD
with RELAY
ENERIZED
CONTROL PANEL
Power ON
Relay
Contact
Closed
Water
Level
Rising
ENERIZED
CONTROL PANEL
Power ON
Relay
Contact
Open
High
Cutoff
Condition
1.
2.
3.
REFERENCE
PROBE
13
17
HIGH
CUTOFF
PROBE
CIRCUIT CARD
with RELAY
REFERENCE
PROBE
13
17
HIGH
CUTOFF
PROBE
5A
CUSTOMER
CONNECTION
CUSTOMER
CONNECTION
6
5
5A
6
5
5A
CUSTOMER
CONNECTION
7
8A
8
CUSTOMER
CONNECTION
CUSTOMER
CONNECTION
7
8A
8
7
8A
8
ENERGIZED
ENERGIZED
operation
High Level Alarm – Sequence of Operation – B Card
High Level Cutoff – Sequence of Operation – B Card

12
Low Level Alarm – Sequence of Operation – A Card
Low Level Cutoff – Sequence of Operation – A Card
operation
REFERENCE
PROBE
13
18
LOW
ALARM
PROBE
CIRCUIT CARD
with RELAY
DE-ENERIZED
CONTROL PANEL
Power OFF
Relay
Contact
Closed
CIRCUIT CARD
with RELAY
ENERIZED
CONTROL PANEL
Power ON
Relay
Contact
Open
Water
Level
Dropping
ENERIZED
CONTROL PANEL
Power ON
Relay
Contact
Closed
Low
Alarm
Condition
1.
2.
3.
REFERENCE
PROBE
13
18
CIRCUIT CARD
with RELAY
REFERENCE
PROBE
13
18
13
19
CIRCUIT CARD
with RELAY
DE-ENERIZED
CONTROL PANEL
Power OFF
Relay
Contact
Open
CIRCUIT CARD
with RELAY
ENERIZED
CONTROL PANEL
Power ON
Relay
Contact
Closed
ENERIZED
CONTROL PANEL
Power ON
Relay
Contact
Open
1.
2.
3.
13
19
CIRCUIT CARD
with RELAY
13
19
LOW
ALARM
PROBE
LOW
ALARM
PROBE
REFERENCE
PROBE
LOW
CUTOFF
CUTOFF
CUTOFF
PROBE
REFERENCE
PROBE
REFERENCE
PROBE
LOW
PROBE
LOW
PROBE
Water
Level
Dropping
Low
Cutoff
Condition
CUSTOMER
CONNECTION
10
9
9A
CUSTOMER
CONNECTION
CUSTOMER
CONNECTION
10
9
9A
10
9
9A
CUSTOMER
CONNECTION
10
9
9A
CUSTOMER
CONNECTION
CUSTOMER
CONNECTION
10
9
9A
10
9
9A
Water
Level
Water
Level
ENERGIZED
ENERGIZED

13
troubleshooting
The control panel has been tested before shipment and most issues lie outside
of the control panel e.g. proper probe connections to the control panel and
probe tip level heights in the basin of the cooling tower.
In an effort to troubleshoot the system please check the following:
• Check probe heights in the stilling chamber. The levels may be factory set
but if in question contact your Marley sales representative for level height
information. Probe wire height is secured using an adjustable cord grip
located inside the conduit box located on top of the stilling chamber.
• Check if probe wires are connected correctly at the user terminal strip lo-
cated inside the control panel. Each probe wire is printed with an identifying
number on the black insulation of the wire every few inches. For example
the reference probe is always #13 and needs to be connected to terminal
point #13 in the control panel.
• If probe wires are extended in the field, check to make sure the extension
wire is numbered correctly and connections are secure.
• After time, contaminates may build up on the probe tips. Clean tips with
an abrasive cleaning pad and make sure the tips are screwed in making a
good connection.
• If provided, the make-up selector switch on side of the control panel must
be in AUTO position
Checking the power circuit for the makeup solenoid
• Rotate the selector switch to the HAND position. The solenoid should ener-
gize allowing makeup water to flow into the cooling loop. Inside the control
panel is a single-pole circuit breaker which must be in the ON position to
power the circuit.
Checking control panel functionality
• To determine the control panel works as designed check the green LED
lights on each circuit card and watch the relays change state in the clear
cased relays located on each level card. Refer to the charts on pages 10
through 12 for LED light sequence of operation.
• Another method is to remove probe wiring from the terminal strip and simulate
water level by using jumper wires at the probe terminal points. For example
a jumper wire from #13 to #16 would indicate high-water alarm.

14
parts list
Probe,
Reference/GND
“Tip Only”
Part Number D20718
Threaded Probe Tip Standard
Part Number 2580240
Includes red cap and
small hat-shaped copper
crimp-on connector
Additional part numbers can be found on the next page
Electrode Probe Assembly

15
parts list
Relay Circuit Card
Part Number D55194 – Used for Makeup, High Alarm and High Cutoff (LLC24B2F50N)
Part Number D55195 – Used for Low Alarm and Low Cutoff (LLC24A2F50N)
Part Number Description
2038884 H-O-A Switch
D55194 Makeup Relay Card
D55194 High Alarm Relay Card
D55194 High Cutoff Relay Card
D55195 Low Alarm Relay Card
D55195 Low Cutoff Relay Card
C74516 Standard Probe Sensor (Complete with tip and 30 ft wire)
D20711 Standard Probe Sensor (Complete with tip and 30 ft wire)
D20707 Reference / GND Probe Sensor (Complete with tip and 20 ft wire)
D20712 Reference / GND Probe Sensor (Complete with tip and 50 ft wire)
2580240 Standard Probe Sensor 3.5" Stainless Steel Tip
D20718 Reference / GND Probe Sensor 6" Stainless Steel Tip
203887 Terminal Blocks Kit (2 Gray, 2 Blue and 1 End)
D81756 EMI Filter
D20707 Reference Marked #13
2220852 Makeup On Marked #14
2220854 Makeup Off Marked #15
2220855 High Alarm Marked #16
2220856 High Cutoff Marked #17
2220857 Low Alarm Marked #18
2220859 Low Cutoff Marked #19
C74516 Generic Level No Wire #

16
wiring diagrams – contents
Drawing Number Description Page
08-24248 Makeup High Alarm High Cutoff Low Alarm Low Cutoff 17
08-24233 Makeup High Alarm Low Alarm 18
08-24218 Makeup 19
08-24219 High Alarm 20
08-24220 Low Alarm 21
08-24221 High Cutoff 22
08-24222 Low Cutoff 23
08-24230 High Cutoff Low Alarm 24
08-24231 Low Cutoff Low Alarm 25
08-24232 High Cutoff Low Cutoff 26
08-24228 High Cutoff High Alarm 27
08-24229 Low Cutoff High Alarm 28
08-24225 Makeup High Cutoff 29
08-24224 Makeup Low Alarm 30
08-24223 Makeup High Alarm 31
08-24234 Makeup High Alarm High Cutoff 32
08-24235 Makeup High Alarm Low Cutoff 33
08-24236 Makeup High Cutoff Low Alarm 34
08-24237 Makeup Low Alarm Low Cutoff 35
08-24238 Makeup High Cutoff Low Cutoff 36
08-24239 High Alarm High Cutoff Low Alarm 37
08-24240 High Alarm Low Alarm Low Cutoff 38
08-24241 High Alarm High Cutoff Low Cutoff 39
08-24242 High Cutoff Low Alarm Low Cutoff 40
08-24243 Makeup High Alarm High Cutoff Low Alarm 41
08-24244 Makeup High Alarm Low Alarm Low Cutoff 42
08-24245 Makeup High Alarm High Cutoff Low Cutoff 43
08-24246 Makeup High Cutoff Low Alarm Low Cutoff 44
08-24247 High Alarm High Cutoff Low Alarm Low Cutoff 45

17

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