Marley Liquid Level Control System
Contents
1. Probes Probes 115 VAC 4 AC Line 115 VAC AC Line O Step 3 Step 4 1 Touch a jumper to the H and C terminals Meter 1 Remove the jumper from L to C Meter should read should read infinity open contact 0 ohms indicating contacts have closed 2 Remove the jumper from H to C leaving the jumper Note Check out procedure for 5212 relay uses from L to C in place Contacts should remain open normally open contacts verses normally closed for 5611 See page 10 Checkout Procedure 5611 0000 Relay Low Alarm Circuit Probes 115 VAC AC Line O Step1 1 Disconnect all wires from relay card Connect power to the relay 2 Connect ohmmeter across contacts COM and NC Meter should read 0 ohms closed contact Load Contacts 115 VAC AC Line O Step 3 1 Touch a jumper to the H and C terminals Meter should read infinity open contact 2 Remove the jumper from H to C Contacts should remain open 10 Probes 115 VAC AC Line O Step 2 1 Attach a jumper to C and L probe terminals Meter should still read 0 ohms Probes 115 VAC AC Line O Step 4 1 Remove the jumper from L to C Meter should read 0 ohms indicating contacts have closed Note Check out procedure for 5211 relay uses normally closed contacts verses normally opened for 5612 See page 9 Replacement Part2. Marley Liquid Level Contro System User Manual 98 1482A SPX COOLING TECHNOLOGIES Contents IntrodUCtION m E pt Want Sateen leider dense t tons 2 WING RE D D 3 OPO ATOM ayes cc czsescsteactccnessnsezsehesaghasecbascaed lt cdraeyedssaphabaiascacs Aea a AaS IREE 4 Troubl Shooting 5 58882 retraite eee 8 Checkout Procedure Water Makeup and High Alarm 9 Checkout Procedure LOW Alarm 10 Replacement Parts ic cccscissisiccssstecsssvescs ctu cssevs sacdedesnieccadeseensstisseeccsusexensts 11 SPECITICATIONS ssiri inda ne d ennt reed a i ae ia Naaa 12 Introduction The Liquid Level Control systems are used to accomplish several func tions e Electronic Water Makeup e Low water Alarms e Low water Cutoff e High water Alarms e High water Cutoff The most common application is electronic water makeup This system is used with a remotely installed water solenoid valve to add water to the system as required Conductivity probes are utilized to electronically monitor the water level Problems associated with freezing water lines are avoided in a properly designed system by installing all pressurized water lines in a protected environment Makeup water is added to the cooling system and supplied to the tower through non pressurized self draining lines Low water and high water alarms can be utilized to give warnings as sociated with abnormal operating conditions The system provides dry contacts to interface w
3. e completing the circuit across this probe and the ground reference See Figure 2 At this point the valve is de energized and closes Operation Valve Circuit 115 VAC Complete m Fill Start Figure 2 The high level alarm is provided by the shortest probe and provides warning that the water level is exceeding the proper operational level This alarm signal is produced when the water makes contact across the shortest probe and the ground reference and ceases when the water level drops below this level See Figure 3 High Signal 115 VAC High Normal Figure 3 Figure 4 Operation All the probes are contained in a single assembly and protected by a sheet metal stilling chamber The probe assembly is connected to a bracket for mounting in the cold water basin See Figure 4 All wires are routed to the relay enclosure in a liquid tight conduit Conduit to be routed so relay box is high point in system and probe holder is low point Each function low alarm water makeup or high alarm requires a separate relay All relays are powered by a 115 VAC supply voltage connected to terminals labeled AC line on the terminal strip at the bottom of the relay circuit board Terminals COM NO and NC provide outputs to alarms or fill valves Terminals C L and or H on the terminal strip at the top of the relay circuit board are connected to the probes See Figures 1 2 and 3 Fig
4. ed in USA Manual 98 1482A
5. ith digital control systems or user supplied alarm indicators to signal when corrective action is required Low water cutoffs are commonly applied to protect pumps and basin heaters from operating without water thus preventing costly repairs as sociated with unintended operation 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 Wiring Make Up 0 15 3 and 4 1and2 16 or 17 13 5 and 6 7 and 8 1 and 2 18 or 19 13 9 and 10 11 and 12 1 and 2 N lt 115 VAC solenoids connected as shown 5 Terminal Strip Legend Connection for Outgoing Lines T 2 3n 12 115 VAC Water Make Up High Level Alarm High Level Cut Off Low Level Alarm Low Level Cut Off Connection for Probe Wiring 13 14 15 16 18 19 Note Reference Probe Make Up On Probe Make Up Off Probe High Alarm Probe High Cut Off Probe Low Alarm Probe Low Cut Off Probe Diagram shows internal wiring One relay is required for each alarm or cutoff level Ground screw is provided on the relay panel Relay cards provide dry contacts Power for alarm signals or solenoid valves must be supplied externally 10 amp resistive load or 1 3 hp 120V AC Figure 1 Operation The Liquid Leve
6. l Control System consists of special purpose liquid sens ing relays connected to a probe assembly located in the cold water basin The relay cards are powered by a 115 VAC power supply The relay cards produce a current limited 17 5 VDC signal to detect water level This cur rent is conducted through the water across probes of dissimilar length 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 The longest probe is the ground reference probe and is shared by all the functions of the system For low level control the ground reference probe and a slightly shorter probe provide the circuit The distance from the tip of this 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 See Figure 1 When the water level drops below this level the connection between these probes is broken and the relay contacts transfer Low Signal 115 VAC Min ee Fill control utilizes two additional probes The longest of these two probes determines the level at which fill begins and the shorter probe determines the point at which fill is complete The fill valve opens when the water level drops below the longer probe breaking contact between it and the ground reference The fill valve remains energized until the water level reaches the shorter prob
7. s High Cutoff or Low Cutoff 4 BW Relay 5611 0000 Low Alarm or Low Cutoff 5 BW Relay 5612 0000 High Alarm High Cutoff or Makeup C32349D C32350D C745160 A87493D A87492D 11 Series 56 Relay Specifications ei ia 187 SLOT 2 FLAGES 4 0 3 87 jt 1 5 3 16 3 0 PC BOARD TT 1 25 E PVC SNAP IN MOUNTING TRACK NET WEIGHT 7 25 OUNCES Voltage 120 Volts AC 50 60 Hertz 240 Volts AC 50 60 Hertz Other voltages available on special order Power Required 4 Volt amperes 2 watts Load Contacts Single pole double throw Gold flashed silver cadmium oxide Contact Ratings 10 amperes resistive load or 1 3 hp at 120 Volts AC 6 amperes resistive load at 240 Volts AC or 28 Volts DC Sensing Circuit 17 5 Volts DC open circuit 400 microamperes short circuit Includes a lock in feature for greater versatility Sensitivity 50 000 ohms cm fixed is standard Other sensitivities fixed or adjustable are available on special order SPX COOLING TECHNOLOGIES 7401 WEST 129 STREET OVERLAND PARK KANSAS 66213 UNITED STATES 913 664 7400 spxcooling spx com spxcooling com In the interest of technological progress all products are subject to design and or material change without notice 2009 SPX Cooling Technologies Inc Print
8. ure 5 Operation For a single function system requiring only one relay the relay is housed in a6 x 6 NEMA 4X enclosure normally mounted on the side of the cooling tower For two or more functions relays are located in a 12 x 14 NEMA 4X enclosure and all relay wiring is connected to terminal strips located in the enclosure See Figure 5 Water Makeup High Alarm i High Cutoff or Low Cutoff LE set r ee en a 1121341516171819 40111112 13 14 15 16 17 18 19 AC To To Power Outputs Probes There are two types of relays used in the system The two relays appear exactly alike and are identifiable only by the numbers printed on the circuit board The relay used for low level control is designated TYPE 5611 0000 and is described as direct operation This means that when power is applied to the relay the contacts remain in their normal position until the probe circuit is completed across C ground reference and L low at which time the contacts transfer The relay used for fill control and high level alarm is designated TYPE 5612 0000 and is described as inverse operation The contacts operate the opposite of direct operation transferring when power is applied to the relay and returning to their normal position when the probe circuit across C and H is completed Troubleshooting Trouble Probable Ca
9. use Remedy Tower Basin Overflows Low Water Level Low Level Alarm Fails 1 Faulty Sol Valve 2 Faulty Fill Relay See Checkout Procedure 3 Deposits Plating on Probes 4 Low Liquid Conductivity de mineralized water etc 1 Faulty Sol Valve 2 Faulty Fill Relay See Checkout Procedure 3 Contamination foam in Stilling Chamber 1 Contamination foam in Stilling Chamber 1 Replace Valve 2 Replace Relay 3 Clean Probes 4 Contact Marley 1 Replace Valve 2 Replace Relay 3 Clean Stilling Chamber 1 Clean Stilling Chamber False High Water Alarm 1 Contamination foam in Stilling Chamber 2 Faulty High Alarm Relay See Checkout Procedure 1 Clean Stilling Chamber 2 Replace Relay False Low Water Alarm 1 Faulty Low Alarm Relay See Checkout Procedure 1 Replace Relay Note Checkout procedure for relay circuit boards is provided on pages 9 and 10 Checkout Procedure 5612 0000 Relay Water Makeup and High Alarm Circuits Load Contacts Contacts Probes Probes 115 VAC AC Line 115 VAC AC Line O O Step1 Step 2 1 Disconnectall wires from relay card Connect power 1 Attach a jumper to C and L probe terminals Meter to the relay should still read 0 ohms 2 Connect ohmmeter across contacts COM and NO Meter should read 0 ohms closed contact Load Contacts
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