Star-Z 20-1 Hot Water Circulator Pump
Instruction Manual
Wilo-Star-Z 20/1, 25/2, 25/2 DM, 25/6, ZD 25/6
Star-Z 20-1 Hot Water Circulator Pump


General
Installation and service by qualified personnel only
1.1 Fields of Application
This circulator is suitable for drinking water only. Series Star-Z circulating pumps are suitable of handling liquids in the fields of service/drinking water and food-related liquids.
1.2 Product Information
1.2.1 Technical Data
Maximum working pressure: 10 bar Minimum inlet pressure at the suction port at 40 °C: 0.5 bar (50 kPa) at 65 °C: 0.2 bar (20 kPa)
Permissible temperature range of fluid: Service water systems +2°C up to +65°C
Maximum permissible ambient temperature: 40°C.
Mains supply voltage: refer to the nameplate.
Input power P 1: refer to the name plate.
Max. motor speed: refer to name plate Pipe connection size: (screw-ended pump)
Z 20/1: R 1/2, DN15 (G: R1)
Z 25/2: R1, DN 28 (G: R1/2)
Z 25/6: R1, DN 28 (G: R1/2)
ZD 25/6: R 1, DN 28 (G: R 1½)
The minimum inlet pressure at the pump suction port must be maintained to avoid cavitation noise.
Safety
These instructions contain basic references to safety aspects that must be strictly adhered to. It is therefore imperative for the Installer and the Operator to carefully read these instructions prior to installation and commissioning. Please observe, not only the safety rules under the main heading safety considerations but also those added and specially marked under the ensuing headers.
2.1 Safety Symbols contained in these Instructions
Safety rules contained herein which, if not complied with, may be harmful to persons are especially highlighted by the following danger symbols:
Danger from general causes:
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Danger from electrical causes:![]()
Safety references which, if not complied with, may cause damage to the pump/plant or impair its function is highlighted by the word:
ATTENTION!
2.2 Trade Qualifications
Only suitably qualified personnel may work on this equipment.
2.3 Dangers from Non-Observance of Safety Rules
Non-observance of safety references may cause bodily harm to persons or damage to the plant. Failure to comply with safety references could invalidate the warranty and/or damage claims. In detail, non-compliance may, for example, cause the following dangerous situations:
- failure of vital plant functions or damage to pump/plant,
- causing personal injury from electrical and/or mechanical causes.
2.4 Safety Consideration for the Operator
Local regulations for the prevention of accidents must be observed.
Danger from electrical energy must be excluded (conforming to local or general regulations such as IEC, VDE, etc.).
2.5 Safety Considerations for Inspections and Installation Work
It is the Operator’s responsibility to ensure that inspections and installation work are carried out by authorized and qualified personnel only, having themselves made fully conversant with these instructions.
Work must principally be carried out only with the plant switched off and at a complete standstill.
2.6 Arbitrary Alterations and Spare Parts Procurement
Any alterations to the plant are only permitted in agreement with the manufacturers. Original spare parts and authorized accessories serve safety and reliability. The use of unauthorized parts could invalidate any claims for consequential damages.
2.7 Non-Permissible Operating Conditions
Operational safety of the plant is only ensured if used in accordance with Chapter 1 of these instructions. The limits stated in the catalog/data sheets must not be exceeded under any circumstances.
Transport and Storage
ATTENTION!
The pump must be protected from moisture and mechanical damage at all times during transport and intermediate storage.
Description of Product and Accessories
4.1 Description of Water Service Pumps
Series Star-Z circulating water service pumps have been specially designed for use in conjunction with domestic/drinking water service systems.
They are, by material selection and design, corrosion proofed against any residual parts in domestic/drinking water. Speed setting: Z 25/6 and ZD 25/6 pump is equipped with a rotary switch in the terminal box to enable manual; 3-speed control [1 – 2 – 3)].
At minimum speed, the maximum speed is reduced to approx.
40 …50%. The power input is reduced to approximately 50 %.
Particular features of the pumps
Double pumps contain two identically constructed pump heads in a common pump housing with an integrated change-over flap. Each pump can run in a single mode, and both pumps can also run simultaneously in parallel mode. The operating modes are main/reserve operation or incremental/peak-load operation. The pump heads can be selected in different capacities. Double pumps are suitable for adapting a pipe system to suit individual load characteristics.
4.2 Scope of Supply
- Pump, complete.
- Installation and Operating
Instructions.
4.3 Accessories
Accessories available and/or required on separate order:
- Union for pipe connections,
- S1R-h plug-in timer module for 1-phase motors only, except Z 25/6.
4.2 Scope of Supply
- Pump, complete.
- Installation and Operating
Instructions.
4.3 Accessories
Accessories available and/or required on separate order:
- Union for pipe connections,
- S1R-h plug-in timer module for 1-phase motors only, except Z 25/6.
Siting/Installation
5.1 Installation
- Install the pump only after all welding/soldering on the pipe system is completed and the pipe system has been thoroughly flushed out to be clear of foreign matter and impurities, as these may cause damage to the pump.
- Mount the pump in an easily accessible position in order to facilitate later inspection and exchange.
- If used to handle domestic/drinking water a non-return valve must be provided and installed at the discharge side.
- To avoid draining and re-filling the whole of the pipe system on the exchange of the pump it is recommended to provide and install isolating valves at the suction and discharge ports of the pump, to be positioned in such a way to prevent leakage dripping on the pump motor or its terminal box.
- The pump to be mounted with the shaft in the horizontal plane in such a way that it is not stressed by the pipework. Observe mounting positions as shown in Fig. 1.
- The arrow on the pump housing indicates the direction of flow (Fig. 2, Pos. 1).
ATTENTION!
Star- Z 25/2 DM:
The motor terminal box must not face downwards to avoid possible moisture entry. If necessary, rotate the pump head after undoing the screws holding the stator housing.
ATTENTION!
Take care not to damage the housing gasket.
- Due care must be given that free ventilation is not restricted to pumps equipped or refitted with plug-in modules.
ATTENTION!
Thermal insulation of the pump, if applied, must be restricted to the pump’s housing only. Ensure that drain holes at the motor flange remain fully open (Fig. 2, Pos. 2).
5.2 Electrical wiring
- Electrical work is to be carried out by qualified and licensed electricians in strict conformity to ruling national conditions and local regulations.
- All wiring and external switchgear to comply with ruling local regulations (use of conduits, all-pole switches, air gaps, etc.) in accordance with the latest edition of IEE wiring regulations).
- In order to preserve protection against moisture entry and to ensure a firm gland grip, the mains cable must have a sufficiently large outside diameter (f.e. H 05 V V-F 3 (4) G 1,5).
- Cable leads are to be routed in such a way as to avoid any contact with pipework and/or pump or stator housings.
- Check available power supply and voltage.
- Observe pump name plate data
- All wiring is to be carried out according to the wiring diagram (Fig. 4/5):
- 4: 3~400/415 V, 2a:non-overloading
- 5: 1~230/240 V, 2b:non-overloading
- Observe locally ruling earthing regulations.
Commissioning
6.1 System filling and venting
Ensure that the pipe system is properly filled. The pump vents itself automatically after a short operational period. Short-term dry-running will not harm the pump. If necessary, the pump can be directly vented in accordance with the following procedure:
- Switch-off pump,
- close discharge isolating valve,
- Carefully slacken and remove the central access plug using a screwdriver (Fig. 3).
- Depending on the liquid temperature and system pressure, hot liquid or vapor can be released when undoing the central access plug. Beware!
The danger of scalding!
- Protect electrical parts from leaking water,
- switch-on pump again,
- after 15 … 30 secs close the access plug again,
- open the isolating valve again.
ATTENTION!
It is possible that the pump shaft jams with the access plug open, depending on system pressure.
- The pump can become extremely hot, depending on the operating state of the pump or pipe system (fluid temperature).
Beware of scalding when touching the pump!
6.2 Pre-Start Adjustments
- The direction of rotation check on 3-phase motors:
Remove the central access plug at the non-drive end of the motor. Briefly switch on the motor and check whether the sense of rotation corresponds to the arrow on the nameplate; if necessary, change any two-phase wires.
Maintenance
Prior to maintenance or repair work switch off the pump and secure it against unauthorized switching.
Fault Findings Causes and Remedies
8.1 Pump is switched on, but fails to run:
- Check power supply fuses.
- Check voltage at pump terminals (refer to name plate data).
- Check capacitor size (refer to name plate data!).
- The rotor shaft has jammed, e.g. by incrustations.
Remedy: Remove the central access plug, and check the free movement of a shaft or free respectively at the slotted shaft end by means of a screwdriver.
Observe safety procedures as for 6.1!
At high water temperatures and system pressures, close isolating valves at both pump ports. First, allow the pump to cool down.
8.2 Noise
- Cavitation due to insufficient inlet pressure.
Remedy: Increase system pressure within permissible limits.
If the fault cannot be located or rectified, please contact your nearest Wilo representative.
Spare Parts
State all nameplate data when ordering spare parts.
Spare parts
Spare parts are ordered via a local specialist dealer and/or Wilo customer service. In order to avoid queries and incorrect orders, make sure to mention all data indicated on the rating plate when placing your order.
Subject to technical alterations!
Declaration of conformity
according to 2004/108/EC annex IV,2 and 2006/95/EC annex III, B,
Herewith, we declare that this product:
Stratos ECO
Stratos ECO Z
Stratos ECO L
Stratos ECO ST
Stratos ECO BMS
in its delivered state complies with the following relevant provisions:
Electromagnetic compatibility – directive
2004/108/EG
Low voltage directive
2006/95/EG
and with the relevant national legislation.
Applied harmonized standards, in particular:
EN 6035-2-51
EN 61000-6-2
EN 61000-6-3
If the above-mentioned series are technically modified without our approval, this declaration shall no longer be applicable.
WILO SE
Nortkirchenstraße 100
44263 Dortmund
Germany
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Germany
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