Zone Valve Brands, Types and Applications
Zone valves serve the purpose of controlling supply of water to hydronic, radiant or geothermal zones and fan coils, in order to maintain desired temperatures. In a typical residential heating application, where boiler or other heat source produces hot water, installing zone valves will allow for independent temperature control in each room or floor via the thermostat. Multiple zone valves are commonly installed in combination with a zone valve control, which serves as an intermediary between the boiler, circulator pump, zone valves and thermostat(s) and allows for better control and simplified wiring.
Zone Valve Anatomy
The two main components of a zone valve are valve body and an actuator head (with a motor which rotates the valve shaft to a closed or open position). This design allows to replace actuator or actuator motor if it stops functioning without removing or replacing the entire valve. A typical zone valve also has a lever which allows to manually open or close the valve for repairs, maintenance and other purposes.
NC - Normally Closed and NO - Normally Opened zone valve types
Zone valves are either "normally closed" (NC) or "normally open" (NO) with former being the most common. The NC valves are closed by default (when power is off) and only open when power is supplied. The opposite applies to the NO valves. Without any power present, a zone valve returns to its' original state (NC or NO).
Difference between 2, 3 and 4-wire zone valves
Most zone valves today are either 2-wire or 4-wire. In 4-wire zone valves, 2 wires are dedicated to an end switch. 3-wire valve only have (1) wire or terminal connection dedicated to the end switch - this can often be found in older models. The purpose of the end switch is to delay start of the circulator pump until the valve is fully opened (preventing premature wear and tear of components).
Wiring - Terminal Block or Leads
Zone valves with terminal block connections have screw terminals to which the installer must connect the wires from the control panel. Valves with pre-installed leads or wires (usually ~18-20" in length) can be easier to install when control panel is in close proximity to the valve, eliminating the need to measure, cut, strip and secure the wires.
Zone Valves by Taco
Taco manufactures a wide array of products for heating and cooling zone control with application-specific zone valves designed to meet the individual project needs. Taco zone control valve series include the gear-driven, energy-efficient Sentry series and heat-motor type, heavy-duty classic 570, 560, 550 and geothermal series for hydronic, radiant, geothermal and other hot water heating and chilled water cooling applications.
Zone Valves by Honeywell
Honeywell brand zone valves sold at PexUniverse include 2-way V8043 series with terminal connections or wire leads and end switch options. Honeywell zone valves are among the most popular in the industry and can be used for applications such as baseboard or radiator heating, radiant floor heat, chilled water cooling and others. Removable actuator head and replaceable motor makes servicing the valve easy and does not require shutting off the water supply.