21
Sequence of Operation / Settings
Priority switch OFF
Master / Slave switch: Master
Status During Priority switch: OFF
•
A demand occurs from any T-stat (T-stat
closes TT terminals). The “PUMP ON” LED
illuminates for that zone.
•
ZSR control sends 120 VAC to the
corresponding zone pump and the primary
pump outputs, XX contacts close to signal
boiler of a demand.
•
When the demand from the T-stat is satisfied
(T-stat opens TT terminals), the XX contacts
are opened, the “PUMP ON” LED turns off and
the 120 VAC to the zone pump and primary
pump outputs are turned off.
•
ALTERNATE WIRING: The boiler pump can be
controlled by the Mod/Con boiler if equiped to
do so.
Description of terminals
= Ground
N
= Neutral (Common leg of 120 VAC)
L
= Line (Hot 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.
Dip switch description
Master / Slave: Used when joining 2 or more
controls together. Only one Master per group
Priority OFF / Priority ON: Used to set Zone #1
as the priority zone. All other zones will hold off
during priority. Priority has a one hour time out
feature to prevent freeze up.
Primary OFF / Primary ON: Sets the status of the
primary pump when there is a priority call. This
allows the DHW pump to be on either side of a
hydro separator.
Exercise OFF / Exercise ON: When enabled the
pumps will rub for 30 seconds after 72 hours
without a demand.
Post Purge OFF / Post Purge ON: Allows the DHW
pump to run for 2 minutes after the DHW demand
has been satisfied.
WARNING:
NEVER CONNECT R & C DIRECTLY,
this will be a direct short on the 24 VAC supply
