Motorised valve heads (diverter valves)

Motorised valve heads (diverter valves)

Reasons a motorised valve head will fail to start:

  • Motorised valve head lead faulty
  • Burnt out motor windings
  • Motor axle/spindle seized
  • Faulty printed circuit board

These devices are energised or de energised (via the printed circuit board) to operate a motorised axle/spindle. The movement of the motorised spindle communicates with the diverter valve via a bobbin assembly, controlling the path of heated primary water, either to the secondary plate exchanger or to the central heating circuit.

To test a motorised valve head lead:

240v Warning Sign240 V LIVE TEST

Lead:
Set multimeter to correct voltage scale and check at connections

Central heating on:240Vac between connections 1 and 2 25Vac-35Vac between connections 2 and 3Hot water on:240Vac between connections 2 and 3 25Vac-35Vac between 1 and 2.

Incorrect voltages maybe faulty printed circuit board or lead – needs further investigating. Correct voltages but motor axle not moving – replace motorised valve head

To test motorised valve head:

Set multimeter to Ohms scale and measure coil resistance:

0 Ohms between connections 1 and 3
9.6 K Ohms between connections 1 and 2 (resistance may vary)
9.6 K Ohms between connections 1 and 3 (resistance may vary)

Motor axle retracts on hot water or hot water pre-heat facility – ok
Motor axle visible on heating – ok

Got the right tools for your trade?

Heating Engineer’s Toolkit