Two-Port Zone Valves for Separate Heating Zones
Two-port zone valves isolate individual circuits — upstairs and downstairs heating, or a separate hot water loop — so each can be called for independently.
Two-port zone valves isolate individual circuits — upstairs and downstairs heating, or a separate hot water loop — so each can be called for independently. Homes with more than one heating zone usually have one per zone.
What it does
A spring-return actuator opens the valve when its zone calls for heat and closes it when satisfied, stopping water flowing round a zone that isn't asking for warmth.
How it fails
The actuator motor burns out, the end switch that confirms the valve is open fails, or the valve seizes shut or open with age and debris.
Repair or replace
The actuator head clips off and can be swapped without disturbing the pipework in most cases. A seized valve body usually needs full replacement.
Questions we get asked
Is this gas or electrical work?
It's low-voltage electrical and heating-circuit work, not gas work, though on a gas boiler installation we'll usually check it alongside the appliance.
Why do I have zone valves and my neighbour doesn't?
It depends on whether the heating was designed with separate zones — a single-zone system doesn't need them.
Can a faulty zone valve damage the boiler?
A valve stuck closed on every zone can cause the boiler to overheat against a blocked circuit, so it's worth fixing promptly rather than leaving.