Controls repair
Three-port and two-port valve faults
If your heating comes on whenever you run hot water — or a zone won't shut off — the motorised valve is the first suspect. It's a cheap component doing a lot of work, and its actuator head is a common failure point.
For: Homes with cylinders and zoned systems
Head or body?
Most failures are in the actuator head, which can be swapped without draining the system. Only when the valve body itself is seized or leaking does the job need a drain-down. Diagnosis is simple: manual lever operation and continuity testing at the wiring centre distinguish the two in minutes.
Included in the repair
- Wiring centre continuity check to confirm call signals reach the valve
- Head-only replacement where the body is sound
- Full valve replacement with new isolation where corrosion warrants it
- System recommissioned with correct hot-water priority behaviour verified
Frequently asked
- Is an S-plan better than a Y-plan?
- Two separate two-port valves (S-plan) give cleaner zoning and simpler fault finding. On a system rebuild we'd normally propose it.
- Why does the pump keep running?
- Usually the valve isn't reaching its end switch, so the boiler and pump never see the demand end.
- Can I still use the heating meanwhile?
- Often yes, by setting the valve's manual lever, but it's a stopgap not a fix.
Cheap fault, common misdiagnosis
Valve faults are regularly blamed on the boiler or the thermostat. Testing the wiring centre first avoids replacing parts that were never faulty.
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