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STULZ GPS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL1.4General DesignGPS models are designed to meet a wide range of application requirements, as defined by pressure drop flow rate andefficiency. They are selected for a given application using theperformance curves shown in Appendix A on page 18.Figure 1 on page 4 illustrates a typical single pump GPSunit and identifies its major components. Figure 2 on page4 illustrates a typical dual pump unit.Pump motors range from ½ to 10 HP, with two or three pumpvariations available for most HP ratings. Pumps are classifiedas type “A,” “B” and “C,” with the letter incorporated as a suffixin the unit model number. These letters roughly correspond todifferent application requirements, where: “A” models are ideal for applications with high head pressures and low flow rate. “B” models are best for average head pressure and flowrate to achieve higher efficiencies. “C” models are designed for applications with low headpressures and high flow rate.1.4.1 PumpPumps are mounted on an aluminum frame with vibration isolators to eliminate noise and vibration during operation. Eachpump is driven by a direct drive motor rated for continuousoperation.1.4.2 Pump MotorPump motors are rated at the horsepower indicated by the unitmodel number. The pump motor has individual motor contactors. Each pump motor is protected from over-current by fuseslocated in the electric box.1.4.3 Electric BoxElectrical components are protected in a NEMA 3R enclosurelocated on the front of the unit. The electric box has a lockablefront access door which is safety interlocked with the servicedisconnect switch to prevent the door from opening when theswitch is in the ON position. The switch must be turned to OFFto gain access to the electrical components.The service disconnect switch may be used to turn the unitoff for emergency shutdown or during routine maintenance.The handle of the switch may be locked in the “Off” position toprevent unintended activation.1.4.4 Expansion TankThe automatic air vent includes an air separating trap and liquidcontrol baffle to assure unrestricted airflow to the tank and airfree liquid flow from the tank. It also includes a manual vent foradjusting the air volume in the tank. The expansion tank is tobe installed at the highest point of the glycol system with theair vent facing down.WARNINGInstall the tank with the two vent openingsfacing down. The air vent must be installedon the underside of the tank facing downwardto avoid dangerous pressure building insidethe tank.1.4.5 Flow Switch (Dual Pump Systems)A field-installed flow switch verifies fluid flow while the unit isoperating. If flow is lost for at least 10 seconds, (the time delayis adjustable), the unit automatically switches operation fromthe primary pump to the back-up pump. See “Table 1. PumpTiming Adjustments” on page 4 for information about setting the time delay.1.4.6 Pump Selector Switch (Dual PumpSystems)The pump selector switch is mounted on the front of the pumppackage electric box. It is used to select which pump—A orB—operates as the primary pump.1.4.7 Optional Automatic Pump SequencingTimer (Dual Pump Systems)Also called a “lead/lag switch”, this option provides equal pumprun time by automatically cycling operation between the twopumps. The adjustable timer is typically set to rotate pump dutyevery 7 days of operation. A selector switch labeled “Manual/Auto” is provided with the automatic pump sequencing option. The switch must be set to “Auto” to enable automaticsequencing.See “Table 1. Pump Timing Adjustments” on page 4 forinformation about setting the timer.A 15 gallon expansion tank stores excess coolant as it changesin volume due to thermal expansion. The expansion tank is ratedat 75 psi; inlet/outlet holes are 3/4” NPT. The tank is providedwith a field installed automatic air vent.3

STULZ GPS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL1.4.8 Pump Timing AdjustmentsThe following timing adjustments can be made to the GPS unit. See “Figure 9. Electric Box Components” on page 10 forthe location of electric box components referenced in the following table.Table 1.Pump Timing AdjustmentsTimerComponentLocationTiming RangeFlow Loss TimerFlow Delay TimerElectric BoxVariable. Consult STULZ ProductSupport for assistance.Pump Sequencing TimerSmart RelayElectric BoxPer component control labels.WEATHER COVERPUMPINLETSERVICEDISCONNECT SWITCHELECTRIC BOXOULETRECOMMENDED ENTRYLOCATION FOR FIELD WIRINGELECTRIC BOXMOUNTING HOLES (4)Top View- Weather Cover RemovedFigure 1.Front ViewTypical Layout- GPS with Single PumpPUMP BAUTO SEQUENCINGSELECTOR SWITCH (OPTIONAL)PUMP SELECTORSWITCHWEATHER COVERPUMP ASERVICE DISCONNECTSWITCHELECTRIC BOXINLETRECOMMENDED ENTRYLOCATION FOR FIELD WIRINGOULETELECTRIC BOXMOUNTING HOLES (4)Top View- Weather Cover RemovedFigure 2.4Front ViewTypical Layout- GPS with Dual Pumps

STULZ GPS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL2.02.1INSTALLATIONReceiving the EquipmentYour GPS unit has been tested and inspected prior to shipment. To ensure that your equipment has been received inexcellent condition, make a visual inspection of the equipmentimmediately upon delivery. Carefully remove the shippingcontainer and all protective packaging.Check the equipment against the packing slip to verify theshipment is complete. Report all discrepancies to the shipperand/or STULZ.Open the electric box door and thoroughly inspect the unit forany signs of transit-incurred damage. If there is shipping damage, it must be noted on the freight carrier’s delivery formsbefore signing for the equipment. Any freight claims must bedone through the freight carrier; STULZ ships all equipmentFOB factory and is not liable for any damage to equipment intransit. Should any such damage be present, STULZ can helpfile a claim with the freight carrier. Notify the STULZ ProductSupport Group before attempting any repairs. Refer to section5.0 of this manual for instructions.A data package was sent with your unit. It contains this manual, system drawings, applicable SDS’s and other applicableinstructions based on the configuration and options of yourunit. The data package has been placed in your unit in a clearplastic envelope. These documents should be kept with theunit for future reference.2.2Site PreparationSTULZ GPS series units are designed for easy service access.Install the GPS unit in a secure location where it cannot beaccessed by unauthorized personnel and where the mainpower disconnect switch cannot be inadvertently turned off.Allow access to the unit for routine operation, servicing andmaintenance.drawing provided with your unit. If using an overhead liftingdevice, utilize lifting bars that exceed the cabinet width toavoid crushing the sides of the unit. GPS units are shippedon a skid to facilitate moving prior to installation. Units shouldalways be stored in a dry location prior to installation.2.4Mounting/Placement2.4.1 Pump PackageGPS units are designed for mounting to a flat surface. Locatethe unit with the suction side as close to the suction supplyas possible. Install the GPS unit in a secure location withadequate space for accessing components for installation,maintenance and repair procedures. In order to have fullservice access, the unit must be placed so that there are noobstructions in front or overhead. The components may beaccessed from all four sides of the unit and from the top byremoving the cover. The electric box is accessed from thefront of the unit.GPS units must not be located in the vicinity of steam, hot airor fume exhausts. Avoid areas that are prone to flooding. Avoidground level sites that are accessible to the public.Install the unit on a solid base capable of supporting theweight of the equipment. Refer to the installation drawingfor the system weight. The base should be at least 2 incheshigher than the surrounding grade and 2 inches larger thenthe dimensions of the GPS unit base (see Figure 3).In order to reduce the amount of vibration transmitted to themounting surface, insert the factory provided vibration isolators between the GPS unit and the base, as shown in Figure3. Secure the unit with fasteners (supplied by others) so thatthe system will not move during operation.HEX NUTHEX NUTLOCK WASHERFLAT WASHERBUSHINGFRAMENOTEWorking clearance requirements should be established before mounting the unit. Refer to theinstallation drawing provided with your unit for thedimensions of the GPS unit and local and nationalelectrical codes for installation guidelines.FLAT WASHERVIBRATIONPADMOUNTING STUD2.3RiggingFigure 3.Recommended MountingThe GPS unit is designed to be kept level in a vertical position. Move the unit with a suitable device, such as a forklift oroverhead lifting sling, and support the unit from the mountingbase. Avoid dropping or jarring the unit to prevent damageto the motor bearings or pump parts. Use an appropriatecapacity lifting device that can safely handle the weight of theequipment. Weight estimates can be found on the installation5

STULZ GPS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL2) SHUT-OFF VALVES, BYPASS VALVE, FILLVALVES,FLOW BYPASS VALVE, FLOWSWITCH, STRAINERS AND UNIONS ARETO BE FIELD SUPPLIED.Figure 4.Single Pump PipingFigure 5.6Dual Pump Piping

STULZ GPS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL2.4.2 Expansion TankNOTEThe expansion tank must be installed at the highest point of theglycol system with the vent holes facing downward. The pumpshould be at least 3 feet below the height of the expansion tank.Install the automatic air vent in the expansion tank so it facesdownward, as shown in Figure 4 and Figure 5.WARNINGWhen making the connections to the pump(s), aTeflon tape thread sealant is recommended tominimize internal fouling of the piping.2.5.1 Minimum Recommended Suction-SidePipingInstall a concentric reducer at the pump suction openingand make all suction piping at least one size larger than thediameter of the suction inlet. Install a suction strainer witha net area two to three times larger than the suction piping.The piping leaving the heat exchanger should enter the pumpsuction port. Install an isolation valve in the suction line formaintenance purposes.Install the tank with the two vent openingsfacing down. The air vent must be installedon the underside of the tank facing downward to avoid dangerous pressure buildinginside the tank.2.4.3 Flow Switch (Dual Pump Systems)The flow switch (shipped loose) is to be installed directly inthe suction pipeline to detect the total amount of coolantflow. When installing the flow switch, refer to the piping diagram provided with your unit and follow the manufacturer’sinstallation instructions provided in the box with the switch.When installed, the paddle of the flow switch must be allowedto fully travel (swing) to the point where the mechanism of theswitch actuates. If the switch is too high above the body ofthe “Tee” fitting, the paddle could be obstructed by the insideof the fitting, as shown in Figure 6.2.5.2 Minimum Recommended Discharge-SidePipingInstall a concentric reducer at the pump discharge openingand make all discharge piping at least one size larger thanthe diameter of the discharge outlet. Install a check valve inthe discharge line to prevent back flow that may damage thepump on shut down. Install an isolation valve in the dischargeline for maintenance purposes.CAUTIONA bypass flow valve must be provided around thepump suction and discharge connections. Thisprovides a path for the coolant to return to thesuction side of the pump, allowing the pump tocontinuously operate at full speed. This will preventdamage to the pump seals which would result froman insufficient load on the pump and cause themotor to overheat.FLOW SWITCHDO NOT ALLOW PADDLETO STRIKE PIPE FITTINGFigure 6.GOODFlow Switch2.6Utility Connections2.6.1 Main Power and Control Wiring2.5PipingThe pump system will require a field-installed suction lineand discharge line. Refer to the piping diagram providedwith your unit for details. The pump inlet and outlet use NPTfittings. Pipe size may not necessarily be the same size asthe unit connection.Piping should be sized to match the total system pressuredrop and pump capacity. Piping must be sized accordingto the piping distance from the pump to the rest of theequipment. Each valve, fitting and bend in the line must beconsidered in the calculation.The piping should be isolated from the building by the use ofvibration isolating supports. To prevent damage and to reducevibration transmission, use a soft flexible material to packaround the pipes when sealing openings in walls.The GPS unit requires field power and control wiring (seeFigure 7). The unit electric box is provided with main powerand control terminal positions for connection of field-wiring(supplied by others). It is important to identify the options thatwere purchased with the unit in order to confirm which fieldconnections are required. The number of control conductorsneeded will vary depending on the type of control being usedwith your equipment. Refer to the electrical drawing suppliedwith your unit to determine the total number of interconnecting conductors required for your system and for the properwire terminations.The GPS unit is available in the following voltages: 208-230 VAC 1-phase208-230 VAC 3-phase277 VAC 1-phase7

STULZ GPS INSTALLATION, OPERATION, AND MAINTENANCE MANUAL 460 VAC 3-phaseNOTE575 VAC 3-phaseAll wiring must conform to local and national electrical code requirements. Use copper conductorsonly. Wiring terminations may become loose duringtransit of the equipment, therefore, verify all wiringterminations are secure prior to operation.Verify that the main power supply coincides with the voltage,phase and frequency information specified on the systemnameplate. The supply voltage measured at the unit mustbe within 10% of the voltage specified on the nameplate(see Figure 8). The nameplate also provides: The full loadamps (FLA), which is the current that the unit will draw underfull design load; the minimum circuit ampacity (MCA) for wiresizing; and the maximum fuse size (MFS) for circuit protection. The unit's nameplate is located inside the electric box.It is important to note that the control transformer suppliedwith the equipment is sized and selected based upon theexpected load for the system.CAUTIONEntrance holes for the conduit may be made in the side ofthe electric box. The main power wires are terminated at theline side of the service disconnect switch, located within theelectric box. A separate equipment ground lug is providedwithin the electric box for termination of the earth groundwire (see Figure 9).Do not connect any additional loads to the systemcontrol transformer. Connecting additional loads tothe factory-supplied control transformer may overload the transformer and cause the transformercircuit breaker to trip.NOTEWARNINGThe disconnect switch handle must be in the OFFposition to open the electric box.High voltage is used in the operation of thisequipment. Death on contact may result ifpersonnel fail to observe safety precautions.CAUTIONWARNINGImproper wire connections will result in reverserotation of the pump. To correct this problem, exchange any two of the incoming main power wiresat the service disconnect switch. Do not re

for water/glycol-based A/C condensing systems. Any use beyond this is deemed to be not intended. STULZ is not liable for any damage resulting from improper use. The system is designed to be installed outdoors unless otherwise noted on the equipment nameplate. 1.2 Product Description STULZ GPS units are designed to be the most compact and