How to Replace a Motorised 3-Port Valve (UK)
Fit a Honeywell V4073A or Drayton MA1 3-port mid-position valve on a Y-plan heating system.
HoneywellDrayton
Actuator vs body
Actuator only — Honeywell 22750 replacement head clips onto existing body. Full body — 22 mm compression on all three ports, requires drain.
Fit
Wiring: brown (HW), white (CH), orange (call for heat), grey/blue neutral. Confirm at wiring centre before energising.
Frequently asked questions
- Y-plan constantly asks for HW even in summer?
- Actuator microswitch failed. Replace actuator.
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