Microprocessor-Based Leaving Water Control Model AS-UNT33n-l. Installation Maintenance Bulletin No. IM 552 December, 1993 No.

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1 nstallation Maintenance Bulletin No. M 552 December, 1993 Form No Y and Data Microprocessor-Based Leaving Water Control Model AS-UNT33n-l This controller is offered as an option on ALR C vintage and sor-based Leaving Water Controller and accessories contact WHR D vintage packaged chillers where control of Leaving SnyderGeneral Corporation for specification sheets for each Water Temperature is desired. On these units with the control- individual control, er factory installed, the control is preset and calibrated and The controller and sensor covered in this installation and should not need any adjustment other than the control setpoint. maintenance data bulletin are available as substitute replace- For further information on the AS-UNT33n-l microproces- ments for earlier ALR and WHR units. Table Of Contents introductionas-unt33n-l...2 General Description...2 Standard Control Characteristics...2 AS-UNT33n-l Specifications...2 AS-UNT33n-l Accessories...2 nstallation...3 Standards Compliance...3 Dimensional Data...4 Mting...5 Operation...7 Chiller System...7 Leaving Water Temperature Control Operation...7 Johnson Controls Leaving Water Sensor,...8 Hone~ell Leaving Water Sensor...8 Additional Features...9 Settings and Adjustments...l O System Checkout and Troubleshooting...10 Features Requiring Factory Configuration Reset Options Zone Terminal ntroduction Getting Started...ll User s Guide...l3...l3...l4 Making Zone Terminal Adjustments...15 Zone Terminal Glossary...l SnyderGeneral Corporation

2 The AS-UNT33n-l microprocessor-based leaving water control is designed to control multiple capacity steps of coolin9from a single sensor. The AS-UNT33n-l operation is based on an adjustable setpoint and control band as shown in the operation section of this document. f the Leaving Chilled Water Temperature begins to rise to the desired setpoint plus control band/2 (upper limit), Cooling Stage 1 brings on the first stage of cooling. Additional stages of cooling will follow as long as the Leaving Water Temperature remains above the upper limit of the control band. As the leaving water temperature begins to drop to setpoint minus control band/2 (lower limit), cooling stages will ntroduction General Description Standard Control Characteristics begin to de-energize. There will be no energizing orde-energizing of cooling stages as long as the leaving water temperature is between the upper and lower limits of the control band. As a rule, anytime the leaving water temperature is above the upper limit of the control band, stages will be energized, and anytime the leaving water temperature falls below the lower limit of the control band, stages will be de-energized. At the initial start of the unit a time delay will occur. There is a 60-second nterstate On Delay between stages. Each stage incorporates minimum on and off timers with a maximum cycle rate of six cycles per hour. Table 1: Standard Control Characteristics Setpoint DESCRPTON AS-UNT33n-l Range SETTNG 10 F to 60 F (-12-C to +15-C) Adjustable Control Band Range O-F to 10F (O-Cto 60 ) Adjustable nterstate Stages On Delay Between Minimum Off Time (each stage) Minimum On Time (each stage) 60 seconds 5 Minutes 60 Seconds Soft Start During Start-up 50% command over 5 minutes AS-UNT33n-l Table 2: Controller Specific Characteristics CONTROLLER NUMBER OF LEAVNG WATER DESCRPTON STAGES SENSOR AS-UNT330-4or6 Honeywell AS-UNT332-8 Honeywell AS-UNT or6 Johnson Controls AS-UNT Johnson Controls Caution: Offering this control device is not intended to imply that rapid cycling of compressors iscondoned bysnydergeneral. f an application produces rapid cycling, the control and/or the application must be reviewed and altered to prevent compressor failure. Specifications Electrical Ratings : nput voltage and frequency (terminals 24 VAC-COMMON) 20 to 30 VAC at 50/60 Hz (50 Hz requires download.) Power Consumption: 25 VA at 24 VAC and 50/60 Hz nput Signal: Honeywell sensorpositive temperature coefficient of 4.8 ohms/degree F; resistance of 3484 ohms at 77 F. Johnson Controls sensorpositive temperature coefficient of 3 ohms/ Degree F; resistance of 1000 ohms at 70 F. Number of Stages Selection: Refer to Table 5, Figure 1 for stage selection. Temperature Ranges: Ambient: -40 F to +150 F. AS-UNT33n-l Humidity Rating: 5 to 90% RH noncondensing. Leaving Water Sensor: The Honeywell C7173AO 7, Honeywell C7170A 010, or Johnson Controls TE senses Leaving Water Temperature on control terminals A13 and A13 COM. Table 3: Contact Rating CONTACT VOLTAGE (V) NRUSH (VA) RUNNNG (VA) N.O NC, NO. 120/ NC, 120/ Accessories Model No. McQuay Pert No. Quantity Description Application Johnson TE-6313P Outdoor Air Sensor Used for reset of Leaving Water Setpoint. Johnson TE mmersion Sensor (30 ft. cord) Senses Leaving or Return Water Temperature Sensor Well mmersion Well Used with TE Johnson TE-6410S depends on Zone Temperature Sensor Used for zone temperature reset #of zones Johnson AS-ZW Zone Terminal Used for monitoring and local control of designated Honeywell C7173A mmersion Sensor (30 ft. cord) Sensing of Leaving Water Temperature Honeywell C7170A mmersion Sensor (10 ft. cord) Sensing of Leaving Water Temperature Honeywell A Copper mmersion Well Used with C7173AO17 or C7170AO0 Honeywell E Stainless Steel mmersion Well Used with C7173A017 or C77OA1OO Johnson AS-KTOO-O 1 Resetor Test Kit Used for field diagnostics. Page 2 M 552 points

3 nstallation Standards Compliance The UNT Controller complies with the following standards: 1 CSA C22.2 No. 205 UL916 EEE 472 EEE 446 VDE 0871 Class B EEE 587 Category A EEE 518 FCC Part 15, Subpart NEMA CS 2, Part A, Class J All wiring must comply with local codes and ordinances: Disconnect power supply before making connections to avoid electrical shock and/or equipment damage. Check ratings given in the specification and on the product to make sure the controller fits the application. Choose a location for the AS-UNT33n-l controller that is not exposed to the weather and where controls, connections, and the zone bus phone jack are accessible. Mount the controller with three No. 8 screws through the mounting holes in the base. (See Figure 2,) nstall immersion well and sensor bulb in the Leaving Chilled Water piping as instructed bythe installation manual for the unit being controlled. Connect 24 VAC to terminals marked 24 VAC and COM. CAUTON: Never spark the 24 V power leads to check for power. Do not run low-voltage wiring in the same conduit as linevoltage wiring (30 VAC or above) or wiring that switches power to highly inductive loads (such as contractors, coils, motors, or generators). 7. Wire the compressor and capacity controls steps to the individual controller relay terminals as shown in the unit wiring diagram. 8. Adjust SW1 and SW2 on A12 for the appropriate number of cooling stages. The AS-UNT330-l/AS- UNT334-1 is factory set for 6 stages by Johnson Controls. The AS-UNT332-l/AS-UNT336-l is factory set for 8 stages. Refer. o Table 5 and Figure 1. L Table 5: Dipswitch Settings AS-UNT330- Oipswitch ettings Factory Stage Factorv Set Sat Select AS-UNT334-1 AS-UNT 13n-1 Al 1 A12 SW2 10 v 2V A13 A14 A15 A16 Figure 1: Analog nput Switches 4 stage selection (set by others) Swl T v AS-UNT330-1 AS-U NT334-1 SW2 10 v 2V 6 stage selection (set by others) Swl T v AS-UNT332- AS-UNT336-1 SW2 10 v 2V, wardog nputswitches 6 stage selection (set by others) Swl T v M 552 Page 3

4 Dimensional Data Figure 2: Dimensional Data r 1-1eF -. m Ly +mrl3l-,uiuullin u i: ~lll_l 1,0 &p-- L ~ = mounting holes A 7il * o Page4/ M 552

5 Wiring Figure 3: Wiring Diagram (1) DEMAND LMT* 0-10 VDC LEAVNG 25 (-) (+) Al CM A12 SHUTDOWN* COMP LEADLAG* A= T, 00 Al CM A16 h ~~ p +15VDC +15VDC G 24VAC B1 (2) FLOW NTERLOCK B14 ~ g; g;. ; * ndicates z 18 optional 512/518 feature. 24VAC ) ~ n # : (1) Sensor for Outdoor, Return Water, or Zone Temperature Reset optionsare connected to Al-1 and Al-CM. (2) Field connections must be made betweentb3-18 and B-4 for unit to operate. Figure 4: Stage Relay Configuration Note: Refer to Unit Wiring Diagram for Stage Wiring. M 552/ Page 5

6 Table 6: Wiring Location Cross Reference Lead # H~Y# Stages Johnson Controls (JC) AS-UNT33n-l 512 TB3-18 to TB3-29 (4,6,8, Stages) Not Needed (See Note 0 and@) 518 Tb3-29 to TR TB3-18 to 24 VAC 519 TR Common 522 Ground Not Needed Not Needad (See Note@) 525 TB3-23 to TB3-24 Not Needed Not Needed (see Note 0) 527 P to Pi Not Needed or Zone Terminal Adjust A-3 (JC or HN Leaving Water Sensor. See appropriate sensor section) 529 Tl A-CM (JC or HANLeaving Water Sensor. See appropriate sensor section) 400 OHM 7 to 6 4 Stages Resister 600 OHM 7 to e 6 Stages Resister See Table OHM 7 to e 8 Stages Resister 523 Ground 8 Stages Not Needed ,, Not Needed 536 2,, Not Needed ,, Not Needed Not Needed To install Flow Switch Contacts, connect between TB3-18 and UNT To install Time Clock Contacts. connect between TB3-18 and UNT B1-1. ~ The options areas follows. (Option A is standard; options B, C, and D require field download, See Features Requiring Configuration and/or Field Adjustment section for more information): A. The standard is Demand Limit nput. O-1OVDC signal is required. Connect leads to Al-1 and Al-CM on the controller. B. Johnson Controls Outdoor Air Sensor if Outdoor Air Reset is used. C. Johnson Controls Zone Temperature Sensor if Zone Temperature Reset is used. D. Johnson Controls Return Water Sensor if Return Water Reset is used. Page 6/ M 552

7 Operation Chiller System Chiller systems are used to provide cold water for comfort Figure5: Chiller System cooling or process applications. Control of the compressor operation to supply that cold water maybe initiated by sensing Return Water Temperature or Leaving Water Temperature. f precise control of Leaving Water Temperature is desired a AS- UNT33n-1 controller is recommended. LEAVNG WATER SENSOR CONTROL w=ensor J RESET (optional) UMP COOLNG LOAD Leaving Water Temperature Control Operation Leaving Water Temperature will be controlled to the Actual Leaving Water Setpoint. The Actual Leaving Water Setpoint will be a function of what mode of operation the controller is in and if a reset option is used. The Control Band potentiometer located on the front of the controller is used to determine the Actual Leaving Dead Band and Prop Band. Actual Leaving Dead Band: Control Band (A16)/2. Actual Leaving Prop Band: Dead Band * Number of Stages. Example: Control Band = 4 Deg F Number of Stages = 6 Dead Band. 4/2 = 2 Deg F Prop Band= 2*6=12 Deg F As the Leaving Water Temperature rises above the Actual Leaving Water Setpoint, but within the Leaving Dead Band, there will be no increase in the Compressor Command. As the Leaving Water Temperature continues to rise above the Dead Band and into the Prop Band, the Compressor Command will be increased. When Leaving ntegration Gain is used, a Proportional Plus ntegral command will be calculated. As the Compressor Command increases, stages of cooling capacity will be energized. Minimum on, off, interstage times, and cycles per hour attributes will control the stages. As the Leaving Water Temperature decreases towards the Actual Leaving Water Setpoint, the Compressor Command will be decreased. Upon reentering the Dead Band, the current Compressor Command will be maintained. f the Leaving Water Temperature falls below the Actual Leaving Water Setpoint (using the same Dead Band), the Compressor Command will again start to decrease. The Control Band is the non-staging area of the control. Anytime the Leaving Water Temperature isoutside of the control Figure 6: AS-UNT33n-l Leaving Water Control Algorithm Operation l\ J band limits, staging will occur. Anytime the Leaving Water Temperature is within the control band limits, no staging occurs. As shown in Figure 6, with a 45 F setpoint and a 4 F control band setting, stages of cooling energize when the Leaving Water is 47 F or higher. Stages de-energize when the Leaving Water is 43 F or lower (4 F difference). All stages will remain in their current state between 43 F and 47 F. AS-UNT33n-l LED OPERATON The AS-U NT33n-l has one LED for each staged output. The LED on the AS-UNT33n-l will light simultaneously as that stage relay energizes. f the LED is not lit, the stage is not energized. When a stage relay energizes, the normally closed contacts open, and the normally open contacts close, M 552/ Page 7

8 Johnson Controls Leaving Water Sensor Note: Johnson Controls or Honeywell Leaving Water Sensors may be used with the AS-UNT33n-l. Refer to Table 2, page 2. A description of the Honeywell sensor follows the description of the Johnson Controls sensor. Table 7: Johnson Controls Leaving Water Sensor TE Temperature Resistance (OHMS) F c Nickel o i Accuracy can be determined by measuring sensor resistance and making a comparison to the temperature and resistance chart. See Table 7. The thin-film nickel sensor has a reference resistance of 1000 ohms at 70 F (21 C) and a change in resistance of approximately 3 ohms/f (5 ohms/c). See Table 7 for resistance values at selected temperatures. Temperature Resistance (OHMS) F c Nickel Honeywell Leaving Water Sensor The C71 73A and C71 70A are sensors for use in applications requiring a broad temperature sensing range. Unlike thermistors, the C71 73A and C71 70A have a positive temperature coefficient (PTC); resistance increases as the temperature increases. As shown in Table 8, the resistance curve increases by 4.8 ohms per degree F temperature rise [8.6 ohms/c]. Resistance in the sensor wiring positively offsets the temperature sensed by 1 degree F every 4.8 ohms [8.6 ohms/c] of resistance. Use short wire lengths or larger gauge wire when longer lengths are necessary. With an accurate thermometer (+/-1 F [,5 C]), measure the fluid temperature at the sensor location, allowing time for the thermometer to stabilize before reading. Use an ohmmeter to measure the resistance across the sensor wires. Then verify sensor accuracy with the temperature/resistance values in Table 8. Table 8: Honeywell Temperature/Resistance Table for C71 73A, Leaving Water Sensor T~:P or.r~s y OHMS T~~p OHMS y OHMS T~:P OHMS y OHMS T~~P ohms T!:p OHMS , , , , , , , , , ,6 Page 8 M 552

9 Additional The following features are also included with the controller algorithm operation, Where there is a point number specified after the feature name (e.g., A13), a sensor or contact closure input is required. Leaving Water Low Limit f the leaving water sensor reads a reliable value below an adjustable Leaving Water Low Limit (LWLL) for more than 3 seconds, the compressor command will be forced to 0% immediately. Once the Leaving Water Temperature rises above the LWLL by a LWLL Differential (LWLLD), a normal control sequence will be initiated. Default values are 15 F for the LWLL and 5eF for the LWLLD. Leaving Water Low Limit will effect compressor commands only. The default value for the Leaving Low Limit and Differential is adjustable through the Zone Terminal, HVAC PRO Software, or Johnson Controls Facility Management System. Demand Limit nput - Analog nput (All) Demand Limit nput will effect the control strategy as follows. This Al will inversely limit the compressor command for external demand limiting control strategies. As the input goes from 0-10 VDC, the compressor command will be proportionally limited from 100% to O%. For example, if the Demand Limit nput is 5 VDC, the compressor command cannot exceed 50%, if 8 VDC is present, the maximum compressor commands will be 20% and so on. The Demand Limiting function can operate when the control is in the Occupied mode only. Demand limiting will not occur while in the ce Mode. CAUTON: For the demand limit nput feature, use only 0-10 VDC input. Features Cooling Diagnostics The leaving water temperature sensor will be used to determine a drop in leaving water temperature overtime whenever a stage is energized. When a stage is energized, if the Leaving Water Temperature does not drop by 1F in five minutes, this is considered a Cooling Stage Failure. This failure point can be monitored with the use of a Zone Terminal or Johnson Controls Facility Management System. Once a Failure has occurred for a particular stage, the alarm can only be cleared by producing the change in temperature over time or by cycling power. Shutdown Mode (B1-1) When shutdown mode is enabled, all stages will be de-energized. Compressor Lead/Lag Control (B12) f Lead/Lag Control is desired, a B (Binary nput) point can be configured to initiate the mode of operation. When B12is open, circuit 1 isthe lead, When B12isclosed, circuit 2 isthe lead. The lead circuit will not change unless all stages are off. Flow nterlock nput (B14) After a transition from Shutdown Mode or Restart Delay the controller will wait 10 seconds for a verification of Pump Status. f Pump Status is verified during this time, normal control will occur. f Pump Status is not verified, a Pump Failure point will be initiated. f Pump Status had previously been verified, and then is lost for a period of three seconds, the compressor c ommands will be forced to zero. f Pump Status is lost for a period of 10 seconds (Pump Status Delay Timer), the Pump Failure Alarm will be initiated. Once Pump Status is again verified, normal control will occur and the Alarm will be cleared. M 552 Page 9

10 Setting and Adjustments Setpoint Knob HVAC ApplicationsTypical setpoints for HVAC applications or rapid cycling occurs, widen the control band setpoint. range from 42 F to 50 F [5 C to 10C]. These setpoints may SnyderGeneral recommends the following formulator calculatchange due to many factors, including desired space temperi- ing the minimum Control Band Setpoint: ture, required/desired humidity conditions, etc. Temperature drop across vessel (AT) at full load/number of stages +.5 F. Control Band Knob Example: Set for the desired control band in accordance with the following 10 F AT/4 stages of cooling +.5 F = 3 F control band. formula. ncreasing the control band slows down the response of the AS-UNT33n-l. and increases the temperature deviation. Reset Knob Lowering the control band speeds up the response of the AS- This adjustment adds to the Leaving Water Setpoint, when the UNT33n-1, while decreasing the temperature deviation from control is factory downloaded to incorporate an Outdoor Air, Setpoint. Zone Temperature, or Return Water Reset function. The The control band setpoint should be as narrow as possible standard application does not include reset; therefore, this without causing hunting or rapid cycling. f instability, hunting setpoint is disregarded in the algorithm. Equipment needed: 1.Digital Voltmeter 2. Resistor Harness (AS-KT 00-0) Table 9: Troubleshooting System Checkout and Troubleshooting Step Action Verification 1 Disconnect power to AS-UNT33n-l. 2 Disconnect compressor and unloader line voltage power. Check for OVAC at compressor and unloader contactor: 3 Remove Fast-On for Control Band input from A16 and connect resistors as shown. or relays. Al CM A16 E Y + 15VDC & + 4 Set Setpoint knob on AS-UNT33n-l to 10OF (-12C). 5 Turn 24 VAC power onto the AS-UNT33n-l. Check for 24 VAC power at AS-UNT33n-l 6 After approximately 70 seconds, all stages will be All LED s should be ON, The number of stage LED s energized quickly in an ascending order. illuminated should correspond to the control model num 7 Move Setpoint to60 F(16C). ber. f there is a discrepancy, the stage selection DP switch (A12) should be checked for proper settings. to page 2, Figure 1, Table 5. 8 All stages should now be turned off quickly in a All LED s should be OFF. descending order. 9 Remove power from AS-UNT33n-l terminals. Check for OVAC at compressor and unloader contactors 10 Reconnect all wiring as originally installed. or relays. 11 Reconnect AS-UNT33n-l power supply, close System is now operational. Compressor disconnects and place setpoints as desired Refer Page 10/ M 552

11 FeaturesRequiringFactoryConfigurationand/orFieldAdjustment One of the following three reset options can be selected: Outdoor Air Reset, Zone Temperature Reset, and Return Water Reset. The reset options described below operate on identical strategies. The main differences are Setpoints and sensor locations. Leaving Water Setpoint and Leaving Water Reset Band are adjustable using the Setpoint adjustment knobs on the front of the AS-UNT33n-l. Outdoor Air, Zone Temperature, and Return Water High Limits and their respective Reset Bands are values that can be adjusted by use of a Zone Terminal, HVAC PRO Software, or Johnson Controls Facility Management System. Ramping Strategy This ramping strategy applies to all three reset options. When a reset function is used, a Ramping of the Compressor Command is also used. Two adjustable variables setup the ramp as needed. These are Ramp Output and Ramp Time. The Ramp is used to meter the Proportional Command into the Sequencer when conditions don t require a quick startup of all stages. For example, if the Outdoor Air Temperature (OAT) is at Outdoor Air Low Limit (OALL), with OALL being equal to Outdoor Air High Limit minus Outdoor Air Reset Band (OAHL - OARB), the stages do not need to be energized as quickly as they do if the OAT is at the Outdoor Air High Limit (OAHL). When the OAT is at OAHL, the Proportional Command is fed to the Sequencer at the same rate as it is calculated. But if the OAT drops below the OAHL, the Proportional Command is ramped to the Sequencer. This allows for a slower startup of stages. Outdoor Air Reset When this option is chosen, an Outdoor Air Temperature sensor (All )is required. Reset Options (OAT) Four variables are used to setup the reset ramp that calculates the Actual Leaving Water Setpoint. These are: Leaving Water Setpoint (A14), Leaving Reset Band (A15), Outdoor Air High Limit (OAHL); and Outdoor Air Reset Band (OARB). Figure 7: Sensor Wiring for Reset Options: 1 c Al-1 Al-1 COM Figure 8: Outdoor OALL=OAHL - OARB) Air Reset OALL~oAH OARB As the OAT increases above the Outdoor Air Low Limit (OALL), the Actual Leaving Water Setpoint is decreased from its Leaving High Limit (Leaving Water Setpoint plus Leaving Reset Band) to the Leaving Water Setpoint. When OAT reaches the OAHL, the Actual Leaving Water Setpoint equals the Leaving Water Setpoint (A14). f the OAT sensor is missing or unreliable, no reset occurs and the Actual Leaving Water Setpoint equals the Leaving Water Setpoint. f the Leaving Water Sensor (A13) becomes unreliable, the compressor command is forced to 0 %.. Outdoor Temperature Lockout: fan Outdoor Air Temperature sensor is installed and reliable, the shutdown mode is initiated whenever it senses, for more than five minutes, an input below the adjustable Outdoor Temperature Lockout (OTL) Setpoint (45 F). The default value for this Setpoint is adjustable through the Zone Terminal, HVAC PRO Software, or Johnson Controls Facility Management System. Zone Temperature Lockout: When this option is chosen, a Zone Temperature must be made available to the controller, There are two ways to do this. The first is through an adjustable Analog Data Float (ADF) point. With the use of a Johnson Controls Facility Management System, a Zone Temperature or average of multiple Zone Temperatures can be shared with the controller through the ADF point. The second isthrough a Zone Temperature Sensor connected directly to the controller. Regardless of which method is used, the control strategy is the same. M 552 Page 11

12 Figure 9: Averaging Zone Temperature Using Multiple Johnson Controls TE-641OS-2OO-O (METASTAT) Sensors sensor sensor sensor Return Water Reset When this option is chosen, a Return Water Temperature (RWT) sensor (All) is required. Four variables are used to setup the reset ramp that calculates the Actual Leaving Water Setpoint. These are: Leaving Water Setpoint (Ai4), Leaving Reset Band (.15), Return Water High Limit (RWHL), and Return Water Reset Band (RWRB). Figure 11: Return Water Reset LWRB r ~ \ LWSP RWLL=RWHL- RWRB) tirb Four variables are used to setup the reset ramp that calculates the Actual Leaving Water Setpoint. These are: Leaving Water Setpoint (A14), Leaving Reset Band (A15), Zone Temperature High Limit (ZTHL), and Zone Temperature Reset Band (ZTRB). Figure 10: Zone Temperature Reset LWRB ZTU=ZTHL r \ LWSP - ZTRB) As the RWT increases above the Return Water Low Limit (RWLL), the controller decreases the Actual Leaving Water Setpoint from its Leaving High Limit (Leaving Water Setpoint plus Leaving Reset Band) to the Leaving Water Setpoint. When RWT reaches the RWHL, the Actual Leaving Water Setpoint equals the Leaving Water Setpoint (.14). f the RWT sensor is missing or unreliable, no reset occurs and the Actual Leaving Water Setpoint equals the Leaving Water Setpoint. f the Leaving Water Sensor (.13) becomes unreliable, the compressor command is forced to O%. When Return Water Reset is chosen, a Fail Smart Logic option is also available. This option works as follows. f the Leaving Water Sensor (A13) becomes unreliable, the controller switches from Leaving Water control to Return Water control. Actual Return Water Setpoint equals Leaving Water Setpoint (A14) plus an adjustable Leaving Water Setpoint Offset. This value takes into account the temperature differential between Leaving and Return water temperatures, which is typically about 10F. f both the Leaving and Return water sensors are unreliable, the compressor is forced to 07.. As the Zone Temperature increases above the Zone Temperature Low Limit (ZTLL), the controller decreases the Actual Leaving Water Setpoint from its Leaving High Limit (Leaving Water Setpoint plus Leaving Reset Band) to the Leaving Water Setpoint. When the Zone Temperature reaches the ZTHL, the Actual Leaving Water Setpoint equals the Leaving Water Setpoint (.14). f the Zone Temperature sensor is missing or unreliable, or if there is an unreliable Zone Temperature value at the Analog Data Float (ADF) point, no reset occurs and the Actual Leaving Water Setpoint equals the Leaving Water Setpoint. f the Leaving Water Sensor (A13) becomes unreliable, the compressor command is forced to 0%.. Page 12/ M 552

13 Zone Terminal User s Guide ntroduction This user s guide contains step-by-step instructions for using the Zone Terminal (AS-ZTU330-1 ) on a McQuay Reciprocating Chiller (AS-U NT33n-l ). This guide assumes you are familiar with the McQuay Reciprocating Chiller. This guide contains examples of the Zone Terminal (ZT) screen that is standard with the ZT accessory to the McQuay Reciprocating Chiller. User s Guide Organization Three major sections describe how to use the Zone Terminal. ntroduction and Overview Explains in general terms the features and operating modes of the Zone Terminal. Getting Started ncludes an explanation of the keys, displays, and symbols on the Zone Terminal. Also includes an explanation of the Zone Terminal labels and how to install them. n addition, this section instructs the user about handling Alarm Status and connecting the Zone Terminal. Making ZT Adjustments ncludes specific instructions with the Zone Terminal. for making set point adjustments Overview of the zone Terminal The Zone Terminal (ZT) is a hand-held or wall-mounted device that monitors and adjusts your McQuay Reciprocating Chiller information. A standard telephone-style jack connects the ZT to the McQuay Reciprocating Chiller controller directly or through the TE-6410S Zone Temperature Sensor. Features The ZT provides:. Portability. Simultaneous monitoring of three different setting: or values Easy operation with only seven buttons. Flashing numbers to show which items are ZT adjustable Flashing symbols to notify you of alarm conditions Capabilities With the ZT, you can:. Quickly identify a chiller alarm and its location. Monitor and adjust up to 18 different settings To familiarize yourself with the ZT, refer to Figure 12. Fiaure 12: Zone Terminal Template (See Glossary for definition of template terms) so m k\diqlay lndcat3rdmol flaming Signal,CmOf S@hJs Male 2 F-++%% i stage3 Fai 1 stage 3 1 Fai 1 Staa. 4 i Fail Stage 5 St.~e7 Fai 1 stage 7 St,.. 8 M 552 Page 13

14 Operating Modes Two operating modes are included: Monitor and Adjust. Monitor Mode Assoon as the ZT is connected, it completes a self-check, and starts up in the Monitor Mode. Monitor Mode lets you view up to three of chiller settings/sensed values at a time. To allow you to monitor your system, a clear plastic nsert (factory made and installed) relates the ZT s output to your McQuay Reciprocating Chiller system. You can simultaneously monitor the chiller in three ways:. Monitor up to three settings/sensed values, A maximum of six items are accessible in each of the three displays.. Read the symbols to the right of the display numbers to learn the on/off status of various inputs, outputs, or modes (1= On status; O = Off status). This provides continuous monitoring of 18 different statuses (on/off).. Monitor alarm status-a flashing red alarm light and any flashing symbol (1, O, A) visually notifies you when your chiller has an alarm condition. Adjust Mode n Adjust Mode, the ZT displays information in each of the three numerical displays. Typically, the displays are set up so that the relationship between the values can be viewed simultaneously. For example: Display 1 = Lvg Water Temp Display 2 = Lvg Setpoint Display 3. Comp Command This operating mode allows you to adjust any flashing setpoints. Setpoints adjusted by the ZT remain in effect until you change them. Displays, Symbols, Keys and Buttons The Zone Terminal simultaneously displays three set points or sensed values. n addition, flashing symbols indicate when items are in a state of alarm. The keys, buttons, displays, and symbols are explained below Getting Started nstalling the Plastic Labels Note: The insert is normally factory-installed. These steps are required only if the insert is not already installed. To use the Zi_, you ll need the plastic label which is included with your ZT. Table 10: Displays, Symbols, Keys, Buttons Displays, Symbols, Keys, Buttons Display Button Description Select the value you want to 1,2,3 monitor or adjust. Enter Key Use to commit your changes. Adjustments are not processsd unless you press Enter. Flashing Numbers Appear in Display 1, 2, or 3 to indicate numbers you can adjust. Numbers that do not flash are monitor only numbers. Flashing Shows an item is in alarm A, O,(l) Mode Selector Button Press this button to select Operating 1 Modes: Monitor, Adjust, Password, Time Scheduling. A green Mode ndicator light moves through the modes. On/Off Status Observe On/Off conditions of a point Symbols( ) for On/a circle (0) for Off in the HVAC controller with these symbols. A bart(l ) for On, a circle (0) for Off. These are always monitor only items. f the symbol Red Alarm Light Up (f)or Down (/) Arrow Keys flashes, item is in alarm. Flashes anytime a problem exists regardless of which Operating Mode vou have enterad. Use these flashino keys to adjust a number. Appears in the displays, and corresponds to the item you are monitoring or adjusting. nsert The clear plastic nsert is a custom-made label unique to your chiller. Use this nsert when monitoring or adjusting specific items of your system: 1. With the ZT on a flat surface, press the white tab with your index finger (Figure 13). 2. Pull the front cover of the ZT away from the back and slide the nsert into position. 3. Press the ZT together, With the nsert in place and the ZT connected, the in the top position of each displav,. lines up with the first word. Figure 13: nstalling the nsert Page 14 M 552

15 Connecting The Zone Terminal You can wall-mount the ZT, or use it as a portable tool for convenient access to any chiller information. McQuay Reciprocating Controller Connection A standard telephone-style jack connects the ZT to a McQuay Chiller Controller directly or through ate-6410s sensor. Figure 15: Connecting ZT to ate-6410s (METASTAT) Sensor Using Coiled 6 to 6 Pin Cable Figure 14: Connecting ZT to a Reciprocating Chiller Controller Using 6 to 8 Pin Cable Pin Connection Open cover. Alarm Status The ZT indicates an alarm as follows (see Figure 12):. The warning signal (s) flashes to the right of the Display ndicator dot ( ) if the system operating values are in alarm.. The On/Off Status bar() or circle (m) flashes when an On/ Off status is in alarm.. The red alarm light to the right of the Mode Selector Panel flashes when any of the above items are in alarm. Alarms cannot be cleared with the ZT. The problem must be corrected by maintenance or repair of the affected item. Making Zone Terminal Adjustments Adjusting Control Settings You can adjust only a flashing number with the ZT. f the number does not flash, that item is a monitor only item. Adjust Control Settings in Display 1,2, or 3 as follows: 1. Press the Mode Selector Button until the green Mode ndicator Light moves next to the word Adjust. 2. Press either Display Button 1, 2, or 3 to locate adjustable items, which are indicated by flashing numbers. f you continue pressing the display buttons, the dot ( ) in each display changes positions and the corresponding number appears. 3, Press the Up (!) or Down(J) Arrow key until you reach the number you want to enter. f you hold down the Up (~) or Down (J) Arrow keys, you can speed through the numbers more quickly. Press Enter. After you press Enter, the numbers stop flashing for a few seconds. This pause tells you the ZT has processed your adjustment. 4. Press any of the Display Buttons to make other adjustments, and repeat Steps 2 and 3. Note: Some adjustable set points have high and low limits beyond which you cannot adjust them. Adjustable Points The following McQuay Reciprocating Chiller points are adjustable by the Zone Terminal. Table 11: Adjustable Points Full Point Name Template name Leaving Low Limit Lvg Low Limit Low Limit Differential ce Mode Setpoint Failsoft Setpoint Low Limit Diff ce mode Setpt Failsoft Setpt Cool Diagnostic Time Cool Diag Time Cool diagnostic Temperature Cool Diag Temp Refer to the Glossary (next section) for definitions of template terms. M 552/Page 15

16 Zone Terminal Glossary Chiller Off A 1 indicates the chiller is in Shutdown Mode. Ckt 2 Lead A 1 indicates Comp Command circuit 2 is lead circuit. The Compressor Command is the percent of Chiller capacity that is required. Cool Diag Time/Temp When a compressor stage is started, the controller must sense the Leaving Water Temperature change (Cool Diag Temp) within a time span (Cool Diag Time) or a Full Stage Alarm will occur, Demand Limit The percentage by which the maximum Compressor Command of 100% is reduced. Failsoft Setpt f the adjustable Leaving Water Setpoint setting ion the face of the controller fails, the failsoft setpoint is the value the Leaving Water Setpoint defaults to. Fail Stage n A 1 indicates a possible fault condition exists. Low Limit Diff The amount the Leaving Water Temperature has to increase above the Leaving Water Low Limit to allow compressors to restart. Lvg Cntrl Band The Leaving Water Control Band is centered around the Leaving Water Setpoint. When the Leaving Water Temperature is within the Leaving Water Control Band, stages will not be energized or de-energized. Lvg Dead Band The Leaving Water Dead Band is one half of the Leaving Water Control Band. Lvg Low Limit When Leaving Water reaches the Leaving Water Low Limit, the Compressor Command will be forced to 0%. Lvg Prop Band The Leaving Water Proportional Band is the Leaving Water Dead Band multiplied by the number of stages, Lvg Reset Band When reset functions are used, the Leaving Water Reset Band is the amount the Leaving Water Setpoint is automatically increased. The Leaving Water Reset Band adjustment can be found on the face of the controller. Lvg Setpoint The Leaving Water Temperature setting by which the controller will control to. The Leaving Water Setpoint adjustment can be found on the face of the controller. Lvg Water Temp of the leaving water from a McQuay Recipro- The temperature cating Chiller. Ramp Output/Time Ramp Output and Time are used to determine softstart. They define the percentage rate of increase for the Compressor Command. Stage n A 1 indicates stage is energized. SnvderGenem ndustrial Park Blvd., P.0, Box 1551, Minneapolis, MN (612) Printed on Recycled Paper Containing At Least 10% Post-Consumer Recycled Material