1 HVACR216 - Hydronics Zone valves. 2 2 way zone valve Hydronic heating systems often use two or more piping circuits to supply heat to different areas

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HVACR216 - HydronicsHVACR216 - Hydronics

Zone valvesZone valves

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2 way zone valve 2 way zone valve

• Hydronic heating systems often use two or more piping circuits to supply heat to different areas in a building.

• Such areas are called zones.

• One device often used to allow or prevent flow in a given zone circuit is called a 2 way zone valve.

• Hydronic heating systems often use two or more piping circuits to supply heat to different areas in a building.

• Such areas are called zones.

• One device often used to allow or prevent flow in a given zone circuit is called a 2 way zone valve.

32 way zone valve2 way zone valve

• Hydronic boiler with three zones• Hydronic boiler with three zones

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• Several types of zone valves are available.

• They all consist of a valve body combined with an electrically powered actuator.

• Several types of zone valves are available.

• They all consist of a valve body combined with an electrically powered actuator.

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Taco Honeywell B & G Taco Honeywell B & G


• The actuator is the device which causes movement of the valve shaft when supplied with an electrical signal (voltage)

• The actuator is the device which causes movement of the valve shaft when supplied with an electrical signal (voltage)

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• Some actuators use small electric motors and a gear train to produce a rotary motion of the valve shaft.

• These type of valves can move from fully closed to fully open in about 3 seconds

• Some actuators use small electric motors and a gear train to produce a rotary motion of the valve shaft.

• These type of valves can move from fully closed to fully open in about 3 seconds

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Electric motor with a gear trainElectric motor with a gear train

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• Others use a heat motor that expands and contracts to produce a linear motion that moves the valves shaft up and down.

• Heat motor types require 2 – 3 minutes from when the electrical signal is turned on and the valve moves to the fully open position.

• Others use a heat motor that expands and contracts to produce a linear motion that moves the valves shaft up and down.

• Heat motor types require 2 – 3 minutes from when the electrical signal is turned on and the valve moves to the fully open position.

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Heat MotorHeat Motor

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Heat MotorHeat Motor

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• On multiple zone systems, a separate zone valve is installed in the line going to or returning from each zone.

• Each zone valve is controlled by its own thermostat

• End switches in each zone valve control the Circulator and/or the burner/burner control

• On multiple zone systems, a separate zone valve is installed in the line going to or returning from each zone.

• Each zone valve is controlled by its own thermostat

• End switches in each zone valve control the Circulator and/or the burner/burner control

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• Zone valves are available in two-wire, three wire, or four wire configurations.

• Two wires are always required to operate the valves actuator.

• The third, and in some cases the fourth wire is connected to an end switch.

• Zone valves are available in two-wire, three wire, or four wire configurations.

• Two wires are always required to operate the valves actuator.

• The third, and in some cases the fourth wire is connected to an end switch.

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• All end switches are wired in parallel• All end switches are Normally Open

• The circulator and burner are also powered when any zone is calling for heat.

• A circulator pump is always required with zone valves.

• All end switches are wired in parallel• All end switches are Normally Open

• The circulator and burner are also powered when any zone is calling for heat.

• A circulator pump is always required with zone valves.

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• End switches

– When the valve reaches the nearly open or fully open position, the end switch closes.

– The switch closure is used to signal other portions of the heating circuit that the zone is “calling” for heat.

• End switches

– When the valve reaches the nearly open or fully open position, the end switch closes.

– The switch closure is used to signal other portions of the heating circuit that the zone is “calling” for heat.

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• When soldering a zone valve to copper tubing the actuator needs to be removed from the zone valve body.

• The disk or ball should be positioned away from the seat to prevent overheating

• When soldering a zone valve to copper tubing the actuator needs to be removed from the zone valve body.

• The disk or ball should be positioned away from the seat to prevent overheating

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• All zone valves have a lever to manually override the motor and to open the valve in emergencies or for servicing.

• All zone valves have a lever to manually override the motor and to open the valve in emergencies or for servicing.

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4 zone hydronic system4 zone hydronic system

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Lever for manual valve operation

Zone valve motor

Valve cover

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Zone ValvesZone Valves

• Both two (2) way and three (3) way zones valves are available.

• The two way zone valve either allows full flow through the valve or totally stops the flow.

• This is the most commonly used zone valve in the residential application.

• Both two (2) way and three (3) way zones valves are available.

• The two way zone valve either allows full flow through the valve or totally stops the flow.

• This is the most commonly used zone valve in the residential application.

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• Another type of zone valve is the Three way zone valve.

• A three way zone valve has an additional port called the bypass.

• When installed in certain piping arrangements, there is always flow through the valve.

• Another type of zone valve is the Three way zone valve.

• A three way zone valve has an additional port called the bypass.

• When installed in certain piping arrangements, there is always flow through the valve.

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• Three way zone valve• Three way zone valve

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3 way zone valves3 way zone valves

• The three way zone valve is useful when flow must be maintained in a certain portion of the piping system.

• This is often necessary in modern low mass boilers with constant firing rates are used

• The three way zone valve is useful when flow must be maintained in a certain portion of the piping system.

• This is often necessary in modern low mass boilers with constant firing rates are used

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• Three way zone valves can also be used as a diverter valve.

• When used in this application, the valve directs the incoming water flow into one of two possible outlets.

• Three way zone valves can also be used as a diverter valve.

• When used in this application, the valve directs the incoming water flow into one of two possible outlets.

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• In some systems, three way zone valve functioning as a diverter valve, are used to direct hot water from the boiler either to the space heating distribution system, or an indirect water heater, but never both at the same time.

• In some systems, three way zone valve functioning as a diverter valve, are used to direct hot water from the boiler either to the space heating distribution system, or an indirect water heater, but never both at the same time.

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2 way and 3 way zone valves2 way and 3 way zone valves

• Most zone valves for residential and light commercial applications operate on a 24 VAC control voltage.

• Most zone valves for residential and light commercial applications operate on a 24 VAC control voltage.

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Taco zone valve wiringTaco zone valve wiring

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Honeywell zone valve wiringHoneywell zone valve wiring

Documents

1 HVACR216 - Hydronics Zone valves. 2 2 way zone valve Hydronic heating systems often use two or more piping circuits to supply heat to different areas