Specification
Effective: December 8, 2020
Supersedes: February 12, 2016
Submittal Data Information
Job: Engineer:
Contractor:
Rep:
ITEM NO. MODEL NO.
101-051
1 2 3 4
ZONE 1
1 2 3 4
ZONE 2
1 2 3 4
ZONE 3
1 2 3 4
ZONE 4
PRIORITY
ZONE
2 WIRE
ZONE VALVE
(NO END SWITCH)
MUST USE JUMPER
TACO
3 WIRE
ZONE VALVE
1
2
3
JUMPER
3 & 4
MOTOR END
SWITCH
4 WIRE
ZONE VALVE
(POWER OPEN,
SELF CLOSING)
JUMPER
3 & 4
POWER
CONTROLS
SEE NOTE
ZVC 404-EXP-4
FOUR ZONE EXPANDABLE
ZONE VALVE CONTROL
24 VAC
FACTORY
INSTALLED
TRANSFORMER
120 VAC
INPUT
WHITE
BLACK
POWER IN
24 VAC
24 VAC
FACTORY
INSTALLED
TRANSFORMER
120 VAC
INPUT
WHITE
BLACK
TO
CIRCULATOR
DRY
CONTACTS
N/O COM N/C
PUMP END
SWITCH
ZONE 4 PUMP
END SWITCH
SLAVE
PRIORITY ON
RESET
POST PURGE ON
PRIORITY PROTECTION ON
PUMP EXERCISE ON
30 SEC/2 WK
MASTER
OFF
NORMAL
OFF
OFF
OFF
4 MIN/24 HOUR
NOTE: When a circulator is used
on the priority zone instead of a
zone valve, jumper 3 and 4 of
the priority zone.
THERMOSTATS (24 VAC)
INDIRECT
WATER HEATER
AQUASTAT OR
THERMOSTAT
T STAT 1
VALVE 1
T STAT 2
VALVE 2
T STAT 3
VALVE 3
T STAT 4
VALVE 4
POWER
LED
INDICATORS
TO: "TT" ON BOILER
TO: "TT" ON BOILER WITH
DHW "TT" INPUT
ZONE 1
ZONE 2 ZONE 3 ZONE 4 NET
EXPANSION
MAIN
PRIORITY
X X X X A B C R W C R W C R W C R W C 1 2
END SWITCH THERMOSTATS (24 VAC PRIORITY
24 VAC ZONE VALVES
ACCESSORY
PORT
PRIORITY
X X
FUSE
5 AMP
FUSE
5 AMP
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B
A
B
A B
N/O
COM
N/C
PUMP END
SWITCH
ZONE 4 PUMP
END SWITCH
X X
DHW
PUMP
SYSTEM PUMP AND BOILER TURN ON WHEN ANY ZONE VALVE OPENS.
DHW PUMP TURNS ON
ONLY WHEN PRIORITY ZONE CALLS.
SECONDARY PUMP COMES ON WHEN ANY ZONE CALLS EXCEPT PRIORITY ZONE.
SYSTEM
PUMP
SECONDARY
PUMP
120
VAC
HOT
NEUTRAL
Optional System
and/or DHW and/or
Secondary Circulators
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Features
Front Diagnostic Lights
Switchable Priority
Built-in Priority Protection
Simplied Wiring
Works with 2, 3, or 4-Wire Zone Valves
Compact Design
Fuse Protected
100% Factory Tested
Two Pump End Switches can control up to
3 pumps; System, Secondary and DHW
Contractor Friendly PC Board Layout
Universal Thermostat Compatibility
24 Volt Power Output for hard wired thermostats
Field Replaceable Transformer
UL Approved
Extended 3 Year Warranty
Additional -EXP Features
Add-on Power Control Plug
Built-in; Post Purge and Pump Exercise Functions
Two boiler contacts, utilizes full
functionality of Mod-Con boilers
Expandable to 20 Zoning Panels
(120 zones if all are 6 zone panels)
Interface with -EXP Switching Relays
The Taco Connection
Combine the reliability of the Taco Zone Valves,
Priority Zoning Circulators, Thermostats, and the
00
®
family of circulators with the advanced features
f the Taco Zone Controls to achieve total system
integration. No matter the application, Taco now
provides the products to maximize system
performance while simplifying both installation
and service.
External Diagnostics
It’s no longer necessary to remove the box cover to
troubleshoot the system. External visible indicator
lights show full functionality of all products wired
to the zone valve controls. When the thermostat
calls for heat, both the appropriate zone valve and
yellow indicator lights are energized. When the
zone valve is fully opened, the end switch relay
and red indicator light is then energized.
Zone Valve Controls
Taco Zone Valve Controls work with two-, three-, or four-wire zone valves. Fully fuse
protected, they also include two isolated end switches and built-in priority protection.
The contractor friendly PC board layout eliminates the problems caused by incorrect
wiring and the “unnished” look of conventional zone valve installations. The sturdy
screw connections add additional reliability, while the external indicator lights provide
instant diagnostic feedback, reducing installation time. All Taco Zone Valve Controls
are UL listed and carry an extended 3 year warranty.
Taco Expandable Zone Valve Controls
Whether you want to expand up to 120 zones or utilize the advanced features of the
Add-on Power Controls, Taco -EXP controls allow for simple integration of advanced
features. Built-in Post Purge and Pump Exercise functions can optimize the operation
of any system.
Zone Valve Controls
Product Number Transformer Transformer Dimensions of Enclosure
Number of Zones Rating Voltage Width Height Depth
ZVC403 3 Zone with Priority 40 VA 120 VAC Input 10-1/4” 7” 2-3/4”
ZVC404 4 Zone with Priority 40 VA 120 VAC Input 10-1/4” 7” 2-3/4”
ZVC405 5 Zone with Priority 80 VA 120 VAC Input 12-1/4” 8” 3”
ZVC406 6 Zone with Priority 80 VA 120 VAC Input 12-1/4” 8” 3”
Expandable Zone Valve Controls
Product Number Transformer Transformer Dimensions of Enclosure
Number of Zones Rating Voltage Width Height Depth
ZVC404-EXP 4 Zone with Priority 80 VA 120 VAC Input 12-1/4” 8” 3”
ZVC406-EXP 6 Zonewith Priority 80VA 120 VAC Input 12-1/4” 8” 3”
The pump end switches are rated 1⁄6 hp, 5 amps at 120 VAC. The main and priority end switch connections are rated 24 VAC, 1 amp.
All thermostat and zone valve connections supply a 24 VAC class 2 output.
Add-On Power Controls*
PC700 Boiler Reset Control
PC702 2-Stage Boiler Reset Control
PC705 Variable Speed Pump Injection Mixing Control
* For use with -EXP controls
Wiring Diagram
Zone Valve Control
2020