DCWW Cynwyd Pumps Control Installation

DCWW Cynwyd Pumps Control Installation

Client: DCWW
Station Name and Location: Cynwyd Sewage Pumping Station
No of Pumps and Installation type: Two Submerged in Wet-well
Operating Arrangement: Duty/standby
Date of Arfon Rewinds Installation: December 2011

In June 2011, Arfon Rewinds were invited to tender by DCWW for the design and installation of the completion of a mechanical and electrical installation at their newly constructed sewage pumping station in the village of Cynwyd, Nr Corwen, North Wales. The Pumping Station had to be designed to accommodate flows from an initial first phase of 20 domestic properties followed by a future second phase of a further 10 properties.

The main criteria for the design was to meet the Water UK standard for Sewers for Adoption 6th Edition to enable the client to future submit a Section 102 agreement for adoption by the local water authority.



Cynwyd Control PanelAfter a successful tender application Arfon Rewinds and its engineers took ownership for the design, installation and commissioning of all mechanical and electrical apparatus. Arfon engineers set the design flow to be maintained at 9 Ltr per second.

A duty standby submersed pump arrangement was installed on a standard guide rail system controlled via a Siemens Hydroranger ultrasonic controller housed in a multi compartment control panel with a standard water authority telemetry system for future alarm monitoring.


Wilo FA-008.23W installed at Cynwyd SPSDescription: Cynwyd Sewage Pumping Station Data
Pump Type: Wilo FA08.23W 3.9kw
Impellor Type: Wilo Single Channel
Number of Pumps: Two (2) off
Method of start: DOL
Pass Forward Flow: 9 L/sec



Arfon engineers worked closely with Wilo UK application engineers to determine the correct pump and control selection was made:-

The following key determining factors had to be accounted for:

  • A maintained pump duty of 9ltrs /sec utilising maximum pump efficiency
  • Pumped free solids passage of 80mm
  • Pump and control design to current adoptable standards
  • Full Telemetry installation to Water authority standard
  • Provision of over-pumping and generator connection in the event of failure


Method of Work and Risks

  1. Method for the project:
    • Cynwyd Wet Well 12 months following InstallationArfon engineers mechanically installed new 80mm discharge pipework in the wet well area
      and continued with the pipework into the discharge chamber, where new check and
      isolation valves fitted to the outgoing rising main.
    • Arfon engineers installed the new control kiosk on the per cast plinth and carried the
      electrical connections to the main incoming isolator and pump control.
    • Functional testing was then carried out on the control panel before a dry run test was
      successful made on both duty pumps.
    • Arfon Engineers then arranged for a full electrical installation test to be carried out before a
      wet test of the pumps.
    • Full documentation inclusive of pump tests, lifting test certification, telemetry commission,
      and electrical test certification was successfully completed and forwarded to the client.
  2. Risks Eliminated:
    • Fully functional sewage pumping with telemetry
    • Large free solids passage of pumps eliminating blockages and resulting failures
    • Full failure contingency with the addition on over pumping and generator faculties


Results and Environmental Efficiencies

Arfon Rewinds engineers undertook a successful pump commissioning test with the following results:

 Pump Details Static Head Total (Bar) Pumped Head Bar) Flow Rate (Ltrs/Sec) Running Current Pump Efficiency
Foul Pump No1 Serial No 650096260 n/a 1.05 9.5 Ltrs/sec 6.6 amp 79%
Foul Pump No2 Serial No650096261 n/a 1.10 9.0 Ltrs/sec 5.9 amp 82%


In the preceding 12 months no pump failures have been recorded, resulting in no operational callouts and hence no operator intervention for clearing blockages.