Discuss Controls and zone valve in the UK Plumbers Forums area at Plumbers Forums


Gas Engineer
Is there anyway of testing electrically with a multimeter or any other way. Of testing that when you turn a room stat up it is creating a demand and opening the zone valve? Thank you

  • Call for demand on the programmer and the room stat down
  • Turn your multi meter to 600~ or what ever is similar. Put one probe into terminal 3 and the other into terminal 5. You should get 0 on the meter
  • Turn the room stat up. You should now get 230-240 on the meter. If you don't the room stat isn't working or the test was incorrect.
  • Now put one probe into 10 and 3. You should still get 230-240 on the meter. If you don't the valve isn't working
  • To confirm you've done the above correctly, turn the room stat down again and testing 10 and 3 you should get 0 on the meter

We've skipped a load of steps to start with, If you don't know much about electrical diagnostics I would start from the beginning and confirm the fused circuit and programmer are all working first.
240v on the orange to blue or green/yellow earth wire
You need to test AC (alternating current) on brown and blue to the valve when the call for heat is there. They are live and neutral to the motor. I would check the live to earth too. The grey is permanent live into a micro-switch and the orange is switched live from the micro-switch to boiler/pump etc.

Using Ohms, you can test the resistance through the synchron motor inside the valve. They can be replaced if it is that. It does not matter which wire off the motor is live or neutral.

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