What are the brass boxes on my boiler pipes?
Those are zone valves. Each one opens the hot water to one part of the house when that area’s thermostat calls for heat. Three valves means three zones, and usually three thermostats.
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From one of our jobs
Zone valves on the piping above a new boiler
Right now: Turn the cold zone’s thermostat up, then feel that zone’s pipe by the valve. Cool means the valve isn’t opening.
A small motor in each brass head opens the valve. The wires run to a zone control, the board that tells the boiler and pump to fire when any zone calls. Most heads have a little lever on the side that opens the valve by hand.
If one zone stays cold while the others heat, the valve head for that zone is the first suspect: the motor wears out and the valve stays shut. It’s one of the more common boiler repairs, and usually a quick one, because the head comes off without draining the system.
Quick answers
What people ask about boiler zone valves
What does a zone valve do on a boiler?
It opens hot water flow to one zone of the house when that zone’s thermostat calls for heat, and closes it once it’s warm.
Why is one zone in my house cold?
Usually a zone valve that won’t open, a thermostat that isn’t calling, or air trapped in that loop.
How do I know if a zone valve is bad?
The thermostat calls for heat but that zone’s pipe stays cool. A tech checks whether the valve head gets power and opens.
Can I open a zone valve by hand?
Most have a manual lever. It can get you heat until the repair, but set it back afterward.
Who repairs boiler zone valves in Northern Virginia?
Call SwiftPro at (703) 997-9757. We repair zone valves, pumps and boilers across Northern Virginia.
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SwiftPro Heating, Cooling & Plumbing
4230 Lafayette Center Dr N, Chantilly, VA 20151
44679 Endicott Dr, Suite 211, Ashburn, VA 20147
SwiftPro Plumber & Water Heaters
4200 Lafayette Center Dr, Suite N, Chantilly, VA 20151
Virginia Class A contractor license #2705192276