Motorised Valve Replacement in Guildford
A homeowner in Guildford reported that their heating was working but they had no hot water, even when the programmer called for it. The boiler was firing for heating but not for ho...
Response time
Booked in 2 days
Time on site
2.5 hours
Cost range
£245
Warranty
12 months
The Problem
A homeowner in Guildford reported that their heating was working but they had no hot water, even when the programmer called for it. The boiler was firing for heating but not for hot water. The system had a Y-plan configuration with a single 3-port mid-position motorised valve.
The homeowner had noticed that the motorised valve actuator was making a buzzing noise and was hot to the touch. The lever under the valve body could not be moved manually.
The Diagnosis
We tested the motorised valve and confirmed the actuator motor had failed — the valve was stuck in the heating-only position and would not divert to hot water. The actuator was overheating because the motor was jammed and constantly trying to move.
The valve body itself was in good condition and moved freely when tested manually (after removing the actuator). Only the actuator needed replacing, not the entire valve body — which meant the system did not need to be drained down.
The Repair
We isolated the power to the heating system, removed the failed actuator from the valve body, and confirmed the valve mechanism moved freely. A new mid-position actuator was fitted to the existing valve body and the electrical connections were made.
The power was restored and the system was tested: heating-only mode, hot water-only mode, and both mode. The valve actuator moved correctly between all positions and the boiler responded to each demand. The buzzing and overheating were eliminated.
Diagnosed failed 3-port mid-position actuator
Replaced actuator without draining system
Tested all modes — heating, hot water, and both
Outcome & Advice to the Homeowner
Hot water was restored and the heating system was working perfectly in all modes. The buzzing noise was gone and the new actuator operated quietly and reliably. The homeowner was relieved to have hot water again.
We recommended having the motorised valve checked during the annual boiler service, and advised that the actuator should last 5 to 10 years before needing replacement again.
Job Summary
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