• PRIORITY: This is typically used in domestic hot water
applications where it may be desirable to give hot water
production a priority over space heating requirements for a
certain period of time. Zone 1 is the priority zone and the
functionality is enabled via DIP switch 1. The priority timer is
selectable for 30 or 60 minutes, via DIP switch 3.
• PURGE: In normal operation, the last circulator will stop and
the boiler will shut down as soon as there is no longer a call
for heat. If the purge functionality is enabled via DIP switch
2, the boiler will shut down, but the circulator will continue
to run for 90 seconds to extract additional BTUs from the
boiler.
• EXERCISE: When the exercise functionality is enabled via
DIP switch 4, each circulator will run for 10 seconds after
every 72 hours of inactivity. This prevents scale and other
deposits from accumulating around the rotating parts and
ensures a trouble free start up at the beginning of each
heating season.
DIP SWITCH SETTINGS
Switch
ON
OFF
1
Priority OFF
Priority ON
2
Purge On
Purge Off
3
Priority 30 minutes
Priority 60 minutes
4
Exercise On
Exercise Off
5
Not Used
Not Used
6
Power Delay On
Power Delay Off
MECHANICAL INSTALLATION
INSTRUCTIONS
The pump controller should be securely mounted on a wall
near the pumps using four #8 screws (not included).
DESCRIPTION
The Bell & Gossett ZoneTrol II and McDonnell & Miller Zone-
Smart Pump Controllers are designed to control 120 VAC
circulating pumps in hydronic systems.
Max.
T-stat
Number of
Max. HP
Model
Current
Zones
per Pump
Z-2 / ZS-2
0.085
2
1/3
Z-3 / ZS-3
3
FEATURES
• Indicator lights visible without removing cover.
Power LED will illuminate when input power is applied to the
controller. Zone LEDs will illuminate when relay is energized.
Installation, Operation and Service Instructions
Bell & Gossett
®
ZoneTrol II
™
Models Z-2, Z-3
McDonnell & Miller ZoneSmart
™
Models ZS-2, ZS-3
SAFETY
INSTRUCTION
This safety alert symbol will be used in this manual and on the
unit safety instructions decal to draw attention to safety related
instructions. When used, the safety alert symbol means
ATTEN-
TION! BECOME ALERT! YOUR SAFETY IS INVOLVED!
FAILURE TO FOLLOW THE INSTRUCTIONS MAY RESULT
IN A SAFETY HAZARD.
INSTALLER:
PLEASE LEAVE THIS MANUAL FOR THE OWNER’S USE.
Instruction Manual 210712
REVISION B
UL
®
C
US
LISTED
15 amps maximum combined load.
