27
Sequence of Operation / Settings
Priority Jumper: OFF
Master / Slave Jumper: Master
Status During Priority: OFF
•
A demand occurs from any T-stat (T-stat
closes TT terminals). The “T-STAT CALL” LED
illuminates for that zone.
•
ZVR control sends 24 VAC to the corresponding
zone MOTOR terminals to open the zone
valve.
•
When the end switch on the zone valve closes,
the control sends 120 VAC to SEC PUMP and
SYSTEM PUMP. The “VALVE OPEN” LED
illuminates for that zone and the XX contacts
close to signal a heat demand to the boiler.
•
When the demand from the T-stat is satisfied
(T-stat opens TT terminals), both the “T-STAT
CALL” and “VALVE OPEN” LED’s turn off.
•
24 VAC is dropped from the corresponding
zone MOTOR terminals.
•
If no other zones are calling, power is turned
off to the SEC PUMP and SYSTEM PUMP and
the XX contacts are opened.
Description of terminals
= Ground
N
= Neutral (common leg of 120 VAC)
L
= Line (live leg of 120 VAC)
Thermostat terminals
R = 24 VAC
W = Heat call
C = Common of 24 VAC
Boiler terminals
XX = Dry contacts rated up to 120 VAC, 2 Amps.
Closes when any zone calls including priority.
Typically connected to TT on boiler control.
DHW (ZR/ZC) = Dry contacts rated up to 120 VAC,
2 Amps. Closes only when priority is enabled and
calling. Typically used to close ZR\ZC (120 VAC)
or DHW contacts (24 VAC) on boiler controls
equipped with these features.
Pump terminals
SYSTEM PUMP = Runs when any zone calls for
heat. When priority is enabled, the status of the
pump (on\off) during a priority call is selected via
a jumper
SEC PUMP = Runs when any zone calls for heat
except the priority zone when it is enabled.
PRIORITY PUMP = Runs when the priority zone
calls. A jumper is required between the END
SWITCH terminals when using a pump.
Valve terminals
Motor = 24 VAC to power the zone valve motor
End Switch = Connects to end switch on zone
valve. Must be jumpered if using a 2 –wire zone
valve.
WARNING:
NEVER CONNECT R & C DIRECTLY,
this will be a direct short on the 24 VAC supply
