CALEFFI Z-one ZSR10 Series User manual

NA10334
Z-one™ Relay Multi-Zone Pump Control
ZSR10X series
www.caleffi.com
© Copyright 2014 Caleffi
Function
The ZSR series is multi-zone pump and boiler operating
control for multiple zone hydronic heating or cooling
systems. The ZSR series interfaces with low voltage
thermostats, or any other low voltage controllers having
a switching action. The ZSR series controls up to
3, 4, 5 or 6 heating circulator pumps (depending
on model selected) a primary pump and has LED
indicators to provide functional status and easy system
troubleshooting. In addition, a primary pump system
circulator is switched on whenever any zone calls for
heat.
• Compatible with low voltage 2, 3, or 4 wire thermostats
• R, W, C and TT Comm dual labeling at thermostat terminals
• Z-oneLink unlimited zone expansion
• 120 VAC pump outputs
• Selectable Priority with 1 hour time-out feature
• Selectable Post Purge and excercise
• Dry contacts for DHW (ZR/ZC), capable of switching line voltage
• High capacity transformer
• Large terminal connections
• Simplified wiring with extra ground terminals
• Heavy duty sealed relays
• Fuse protected (with spare fuse)
• Front LED Lights
• 100% Factory tested with 3 year warranty
• ETL Approved
Technical specifications
Materials
Housing plastic: ABS
Front display lights: LED
Electrical knockouts: (12) 1/2" size
Performance
Power supply: 120 VAC, 50/60 Hz
Transformer voltage: 24 VAC
Maximum transformer load: 12 VA (ZSR103/4), 20 VA (ZSR106)
Electrical switch rating: 20A max combined
Electrical switch rating pump output: 120 VAC, 5A each
Dry contact rating, ZR/ZC, DHW, XX: 120 VAC max, 2A each
Replaceable fuses: Type 2AG, 5A slow blow
Temperature limits for:
Shipping and storage max: 110°F (43°C)
Maximum Operating: 110°F (43°C)
Maximum Humidity: 90% non-condensing
Approvals: Certified to CSA C22-2 No.24
Conforms to UL Standard 873
Product Range
Code ZSR103 Z-one™Relay switching relays...............................................................three zone
Code ZSR104 Z-one™Relay switching relays.................................................................four zone
Code ZSR106 Z-one™Relay switching relays...................................................................six zone

SAFETY INSTRUCTION
This safety alert symbol will be used in this manual to draw attention to safety
related instructions. When used, the safety alert symbol means ATTENTION!
BECOME ALERT! YOUR SAFETY IS INVOLVED! FAILURE TO FOLLOW
THESE INSTRUCTIONS MAY RESULT IN A SAFETY HAZARD.
CAUTION: All work must be performed by qualified personnel trained in the
proper application, installation, and maintenance of systems in accordance
with all applicable codes and ordinances.
CAUTION: Electrical shock hazard. Disconnect power before installation to
prevent electrical shock or equipment damage. Make sure all connections
are in accordance with the electrical wiring diagram and in accordance with
national and local electrical codes.
WARNING: Avoid electrical noise interference. Do not install near large
conductors, electrical machinery, or welding equipment. Avoid locations
where excessive moisture, corrosive fumes, vibration, or explosive vapors are
present.
Caleffi shall not be liable for damages resulting from misapplication or misuse of it products.
Dimensions
ZSR106
Six switching relays - Input: 120VAC 50/60Hz 20A MAX
Conforms
toUL 873
4009064
CAUTION:RISKOF ELECTRIC SHOCK - DISCONNECT ALL
INPUTPOWER PRIOR TO SERVICING
Milwaukee,WI 53208 USA
POWER
ZONE 1
ZONE 2
ZONE 3
ZONE 4
ZONE 5
ZONE 6
PUMP
ON
Code Zones A B C Wgt. (lbs)
ZSR103 3 9 1/4"11"3"3.2
ZSR104 4 9 1/4"11"3"3.2
ZSR106 6 9 1/4"11"3"3.2
A
B C
C

Installation
6 Zone
T-STAT 2
C
RW
T T COM
COMMS
DP
DHW
ZR/ZC
X X
T-STAT 3
C
RW
T T C
OM
T-STAT 1
C
RW
T T COM
L
PUMP 2
N
PRIMARY
PUMP
L
PRIORITY
PUMP 1
N
L
POWER IN
N
GROUNDS
L
PUMP 3
N
TRANSFORMER
LN
T-STAT 4
C
RW
T T COM
L
PUMP 4
NL
PUMP 5
NL
PUMP 6
N
T-STAT 5
C
RW
T T COM
T-STAT 6
C
RW
T T COM PWR
ZONE1
ZONE2
ZONE3
ZONE4
ZONE5
ZONE6
DipSwitches
Master Slave
Priority OFF Priority ON
Primary OFF Primary ON
Exercise OFF Exercise ON
Post Purge OFF Post Purge ON
ZSR106
When a zone has a demand from a thermostat (T T or R W) the relay will close
sending 120 VAC to the corresponding zone pump, primary pump and closes
(X X) dry contacts signaling the boiler of a heating demand. Zone 1 can be used
for priority by positioning the Priority dip switch to ON, a demand from T-Stat 1
will activate priority pump 1 and all other zone pumps will be switched OFF, plus
DHW (ZR/ZC dry contact rated to switch max 120 VAC, 2A) will close during
priority. Depending on Primary pump dip switch position, the primary pump will
remain either ON or OFF.
The DIP Switches on the ZSR series can
be positioned for the following operations.
Master / Slave: allows for unlimited
expansion to additional ZSR relays.
Priority OFF / Priority ON: When priority
mode is ON, upon demand, zone 1 will
operate as priority and all other zones
are temporarily switched off (with 1 hour
time-out). When priority mode is OFF, all zones remain active.
Primary OFF / Primary ON: When primary mode is ON, the primary pump will
continue to operate during priority.
Exercise OFF / Exercise ON: When exercise mode is ON, each circulator is
switched on for 30 seconds following 72 hours of inactivity.
Post Purge OFF / Post Purge ON: When post purge is ON, the priority pump
continues operating for 2 minutes after the priority zone is switched off.
6 Zone
T-STAT 2
C
RW
T T COM COMMS
DP
DHW
ZR/ZC
X X
T-STAT 3
C
RW
T T COM
T-STAT 1
C
RW
T T COM
L
PUMP 2
N
PRIMARY
PUMP
L
PRIORITY
PUMP 1
N
L
POWER IN
N
GROUNDS
L
PUMP 3
N
TRANSFORMER
LN
T-STAT 4
C
RW
T T COM
L
PUMP 4
NL
PUMP 5
NL
PUMP 6
N
T-STAT 5
C
RW
T T COM
T-STAT 6
C
RW
T T COM PWR
ZONE1
ZONE2
ZONE3
ZONE4
ZONE5
ZONE6
DipSwitches
Master Slave
Priority OFF Priority ON
Primary OFF Primary ON
Exercise OFF Exercise ON
Post Purge OFF Post Purge ON
ZSR106
6 Zone
T-STAT 2
C
RW
T T COM COMMS
DP
DHW
ZR/ZC
X X
T-STAT 3
C
RW
T T COM
T-STAT 1
C
RW
T T COM
L
PUMP 2
N
PRIMARY
PUMP
L
PRIORITY
PUMP 1
N
L
POWER IN
N
GROUNDS
L
PUMP 3
N
TRANSFORMER
LN
T-STAT 4
C
RW
T T COM
L
PUMP 4
NL
PUMP 5
NL
PUMP 6
N
T-STAT 5
C
RW
T T COM
T-STAT 6
C
RW
T T COM
PWR
ZONE1
ZONE2
ZONE3
ZONE4
ZONE5
ZONE6
DipSwitches
Master Slave
Priority OFF Priority ON
Primary OFF Primary ON
Exercise OFF Exercise ON
Post Purge OFF Post Purge ON
ZSR106
Large screw terminal connections makes wiring easy. Three extra ground screw
terminals connection allows fast grounding of pumps. Pump terminals have 120
VAC outputs for simplified pump connection.
Z-oneLink unlimited expansion allows adding
addition ZSR series relay controls to a Master
ZSR. Communication is accomplished by
connecting three wires (bell or thermostat
wire) to the communication terminals located
in the upper right hand corner. The dip switch
is positioned to Master / Slave position. A
demand for heat from any zone will fire the
boiler and start the pump.
6 Zone
T-STAT 2
C
RW
T T COM
COMMS
DP
DHW
ZR/ZC
X X
T-STAT 3
C
RW
T T COM
T-STAT 1
C
RW
T T COM
L
PUMP 2
N
PRIMARY
PUMP
L
PRIORITY
PUMP 1
N
L
POWER IN
N
GROUNDS
L
PUMP 3
N
TRANSFORMER
LN
T-STAT 4
C
RW
T T COM
L
PUMP 4
NL
PUMP 5
NL
PUMP 6
N
T-STAT 5
C
RW
T T COM
T-STAT 6
C
RW
T T COM PWR
ZONE1
ZONE2
ZONE3
ZONE4
ZONE5
ZONE6
DipSwitches
Master Slave
Priority OFF Priority ON
Primary OFF Primary ON
Exercise OFF Exercise ON
Post Purge OFF Post Purge ON
ZSR106

Inspection
Inspect packages for damage. If damaged, notify the appropriate carrier immediately. If
undamaged, open the package and inspect the device for obvious damage. Return damaged
products.
• Use only copper conductor supply wire suitable for at least 105°C
• All circuits must have a common disconnect and be connected to the same pole of the disconnect
Maintenance and Repair
The Caleffi Z-one™switching relay box contains a spare fuse and requires no maintenance. If
any product fails or is damaged, replace product with functional one.
Mounting
Mount the Caleffi Z-one™switching relay box to a suitable surface. Slotted holes are provided
for mounting purposes. Do not mount to a surface that exceeds 115°F (45°C). The unit must be
only located in dry interior locations. It is not suitable for installation in hazardous locations and
should not be placed close to any electromagnetic fields.
Installation
• Remove cover of relay box.
• Identify the four mounting
holes on relay box, mark on
the wall the desired location of
mounting.
• Drill, anchor, and fasten four
screws for mounting.
• Hang relay box and fasten tight
to desired locations.
• Complete wiring connections
in accordance with terminal
locations.
• Place cover back on relay box.

Cover removal
Hold either the left or the right
end of the box up and at an
angle. Use body for stabilizing
relay box.
Insert screwdriver and push tabs
inward, cover should release from
base.
Roll cover off base.

Example Wiring Diagram
VENT
6 Zone
Z6P
THM 2
C
RW
T T COM COMMS
DP
DHW
ZR/ZC
X X
THM 3
C
RW
T T COM
THM 1
C
RW
T T COM
L
PUMP 2
N
PRIMARY
PUMP
L
PRIORITY
PUMP 1
N
L
POWER IN
N
GROUNDS
L
PUMP 3
N
TRANSFORMER
12/20VA
LN
THM 4
C
RW
T T COM
L
PUMP 4
NL
PUMP 5
NL
PUMP 6
N
THM 5
C
RW
T T COM
THM 6
C
RW
T T COM PWR
ZONE1
ZONE2
ZONE3
ZONE4
ZONE5
ZONE6
DipSwitches
Master Slave
Priority OFF Priority ON
Primary OFF Primary ON
Exercise OFF Exercise ON
Post Purge OFF Post Purge ON
L N G
C1
C2
C3
C4
space heating thermostats
ZSR106
PRIMARY!
PUMP
C1 C2 C3 C4
PRIMARY!
PUMP
4 Zone!
ZSR104
ModCon boiler
with primary/secondary
Please reference Z-one™ Relay wiring guide for complete listing of wiring diagrams.

6 Zone
Z6P
THM 2
C
RW
T T COM COMMS
DP
DHW
ZR/ZC
X X
THM 3
C
RW
T T COM
THM 1
C
RW
T T COM
L
PUMP 2
N
PRIMARY
PUMP
L
PRIORITY
PUMP 1
N
L
POWER IN
N
GROUNDS
L
PUMP 3
N
TRANSFORMER
12/20VA
LN
THM 4
C
RW
T T COM
L
PUMP 4
NL
PUMP 5
NL
PUMP 6
N
THM 5
C
RW
T T COM
THM 6
C
RW
T T COM PWR
ZONE1
ZONE2
ZONE3
ZONE4
ZONE5
ZONE6
DipSwitches
Master Slave
Priority OFF Priority ON
Primary OFF Primary ON
Exercise OFF Exercise ON
Post Purge OFF Post Purge ON
T T
L N G
C1
C2
C3
C4
space heating thermostats
ZSR106
C1 C2 C3 C4
L
N
G
T T
ZR
ZC
outdoor!
temperature!
sensor
boiler!
reset!
controller
DHW!
aquastat
space
heating
demand
domestic water
heating demand
VENT
C5
C5
Non-Condensing boiler with
indirect DHW

Caleffi North America, Inc.
3883 West Milwaukee Road
Milwaukee, WI 53208
T: 414.238.2360 F: 414.238.2366
CALEFFI
6 Zone
Z6P
THM 2
C
RW
T T COM COMMS
DP
DHW
ZR/ZC
X X
THM 3
C
RW
T T COM
THM 1
C
RW
T T COM
L
PUMP 2
N
PRIMARY
PUMP
L
PRIORITY
PUMP 1
N
L
POWER IN
N
GROUNDS
L
PUMP 3
N
TRANSFORMER
12/20VA
LN
THM 4
C
RW
T T COM
L
PUMP 4
NL
PUMP 5
NL
PUMP 6
N
THM 5
C
RW
T T COM
THM 6
C
RW
T T COM PWR
ZONE1
ZONE2
ZONE3
ZONE4
ZONE5
ZONE6
DipSwitches
Master Slave
Priority OFF Priority ON
Primary OFF Primary ON
Exercise OFF Exercise ON
Post Purge OFF Post Purge ON
6 Zone
Z6P
THM 2
C
RW
T T COM COMMS
DP
DHW
ZR/ZC
X X
THM 3
C
RW
T T COM
THM 1
C
RW
T T COM
L
PUMP 2
N
PRIMARY
PUMP
L
PRIORITY
PUMP 1
N
L
POWER IN
N
GROUNDS
L
PUMP 3
N
TRANSFORMER
12/20VA
LN
THM 4
C
RW
T T COM
L
PUMP 4
NL
PUMP 5
NL
PUMP 6
N
THM 5
C
RW
T T COM
THM 6
C
RW
T T COM PWR
ZONE1
ZONE2
ZONE3
ZONE4
ZONE5
ZONE6
DipSwitches
Master Slave
Priority OFF Priority ON
Primary OFF Primary ON
Exercise OFF Exercise ON
Post Purge OFF Post Purge ON
VENT
high flow
resistance heat
source
temperature!
sensor!
(in well)
to / from zone loads
L N G
C1
C2
C3
C4
space heating thermostats
ZSR106
L N G
C7
C8
C9
C10
space heating thermostats
ZSR106
C5
C6
C11
C12
C1 C2 C3 C4 C5 C6 C7 C8 C9 C10 C11 C12
PRIMARY!
PUMP
ModCon boiler with
primary/secondary and
zone expansion

WIRING GUIDE
4009064
Certified to CSA C22-2 No.24
Conforms to UL Standard 873
The ZSR101 is a versatile single relay control with two outputs for operating a 120 VAC pump with boiler enable, or two 120
VAC devices without boiler enable. Features include rear knock outs for 4x4 junction box mounting, convenient pre-installed
jumper for pump operation, and 10 amp total load rating.
The ZSR Series of controls is for zoning using pumps. Up to 6 zone pumps (model dependent) along with a primary pump
can be operated. Zone priority is selectable with 1-hour time-out feature. Other features include pump exercising, selectable
post purge, and 3 pump ground terminals for simplifi ed wiring.
The ZVR Series of controls is for zoning using zone valves. Up to 6 valves (model dependent), along with a system pump,
secondary pump(s), and primary pump can be operated. Zone priority is selectable with 1-hour time-out feature. System
pump status (on\off) during priority is also selectable. Replaceable snap-fi t 40 VA transformer standard for 3 & 4 zone mod-
els – expandable to 80 VA with 2nd transformer. 6 zone model has two 40 VA (80 VA) transformers.
Form 031914 rev.1

2
INDEX
Z-one Relay thermostat connections
Thermostat wiring ........................................................................................................................................................................... 3
ZSR101 - single zone relay
Product overview ............................................................................................................................................................................ 4
Operation and cover removal ........................................................................................................................................................................5
A1 - Single thermostat ...................................................................................................................................................................................6
A2 - Multiple thermostats....................................................................................................................................................................8
A3 - Single master thermostat, with TRVs, variable speed pump.................................................................................................... 10
ZSR103, ZSR104 & ZSR106 - multi-zone pump relay
Product overview ........................................................................................................................................................................... 12
Circuit board .................................................................................................................................................................................. 13
Cover removal................................................................................................................................................................................ 14
Product details............................................................................................................................................................................... 15
B1 - Mod/Con boiler, hydro separator or buffer tank, zone pumps ................................................................................................. 16
B2 - Traditional boiler, indirect DHW w/ priority, zone pumps .......................................................................................................... 18
B3 - Mod/Con boiler, primary loop, closely spaced tees, zone pumps............................................................................................ 20
ZVR103, ZVR104 & ZVR106 - multi-zone valve control
Product overview ........................................................................................................................................................................... 22
Circuit board .................................................................................................................................................................................. 23
Cover removal, Transformer Installation .................................................................................................................................................24
Product details............................................................................................................................................................................... 25
C1 - Mod/Con boiler, hydro separator, zone valves ........................................................................................................................ 26
C2 - Mod/Con boiler, indirect DHW on primary side of hydro sep, zone valves............................................................................... 28
C3 - Mod/Con boiler, indirect DHW on load side of hydro sep, zone valves.................................................................................... 30
C4 - Mod/Con boiler, indirect DHW on primary side of hydro sep, master and slave control ........................................................... 32
C5 - Traditional boiler, indirect DHW (no priority) with valve............................................................................................................. 34
C6 - Traditional boiler with reset control, priority indirect DHW with valve........................................................................................ 36
C7 - Mod/Con boiler, hydro separator, zone valve (more than 6), multiple secondary pumps.......................................................... 38
Caleffi shall not be liable for damages resulting from misapplication or misuse of it products.

3
All Caleffi Z-one controls use the same interface
to connect to thermostats. This interface is
very flexible and allows many different types
of thermostats to be connected to the control
including 2, 3 and 4 wire versions. In addition, any
type of switching device can be used to signal a
heat demand by connecting the R & W (T & T)
terminals together. The terminals are dual labeled
to help simplify wiring.
Z-one Thermostat Connections
6 Zone
T-STAT 2
C
RW
T T COM
COMMS
DP
DHW
ZR/ZC
X X
T-STAT 3
C
RW
T T COM
T-STAT 1
C
RW
T T COM
L
PUMP 2
N
PRIMARY
PUMP
L
PRIORITY
PUMP 1
N
LPOWER IN
NGROUNDS
L
PUMP 3
N
TRANSFORMER
LN
T-STAT 4
C
RW
T T
COM
L
PUMP 4
NL
PUMP 5
NL
PUMP 6
N
T-STAT 5
C
RW
T T COM T-STAT 6
C
RW
T T COM PWR
ZONE1
ZONE2
ZONE3
ZONE4
ZONE5
ZONE6
DipSwitches
Master Slave
Priority OFF Priority ON
Primary OFF Primary ON
Exercise OFF Exercise ON
Post Purge OFF Post Purge ON
ZSR106
Z-one T-stat interface
Description
R = 24 VAC Supply
W = Heat Call
C = 24 VAC Common
Function
R&W: When connected, signals a heat demand.
R&C: Provides 24 VAC to powered thermostats.
There are a few different types of 2 wire thermostats
including bi-metallic, power stealing and battery
powered. All of these thermostats connect in
the same manner to the Caleffi Z-one series of
controls. Connect R to R and W to W. See below.
2-Wire Thermostats
6 Zone
Z6P
T
HM 2
C
R
W
T
T COM COMMS
DP
DHW
ZR/ZC
X X
THM 3
C
RW
T T COM
THM 1
C
RW
T T COM
L
PUMP 2
N
PRIMARY
PUMP
L
PRIORITY
PUMP 1
N
L
POWER IN
N
GROUNDS
L
PUMP 3
N
TRANSFORMER
12/20VA
LN
THM 4
C
RW
T T COM
L
PUMP 4
NL
PUMP 5
NL
PUMP 6
N
THM 5
C
RW
T T COM
THM 6
C
RW
T T COM
PWR
ZONE1
ZONE2
ZONE3
ZONE4
ZONE5
ZONE6
DipSwitches
Master Slave
Priority OFF Priority ON
Primary OFF Primary ON
Exercise OFF Exercise ON
Post Purge OFF Post Purge ON
To connect a 4-wire thermostat to the Z-one
series controls, connect R to R, W to W and C
to C. A jumper in the thermostat is also required
between R & Rh as shown below. Similar to a
3-wire thermostat, R & C from the Z-one Control
supply constant 24 VAC to the thermostat.
4-Wire Thermostats
Three wire thermostats get their power from the
control they are connected to. R & C from the
Z-one Control supply 24 VAC to the thermostat at
all times while the W lead signals a heat demand.
3-Wire Thermostats
6 Zone
Z6P
TH
M 2
C
R
W
T
T COM COMMS
DP
DHW
ZR/ZC
X X
THM 3
C
RW
T T COM
THM 1
C
RW
T T COM
L
PUMP 2
N
PRIMARY
PUMP
L
PRIORITY
PUMP 1
N
L
POWER IN
N
GROUNDS
L
PUMP 3
N
TRANSFORMER
12/20VA
LN
THM 4
C
RW
T T COM
L
PUMP 4
NL
PUMP 5
NL
PUMP 6
N
THM 5
C
RW
T T COM
THM 6
C
RW
T T COM
PWR
ZONE1
ZONE2
ZONE3
ZONE4
ZONE5
ZONE6
DipSwitches
Master Slave
Priority OFF Priority ON
Primary OFF Primary ON
Exercise OFF Exercise ON
Post Purge OFF Post Purge ON
6 Zone
Z6P
TH
M 2
C
R
W
T
T COM COMMS
DP
DHW
ZR/ZC
X X
THM 3
C
RW
T T COM
THM 1
C
RW
T T COM
L
PUMP 2
N
PRIMARY
PUMP
L
PRIORITY
PUMP 1
N
L
POWER IN
N
GROUNDS
L
PUMP 3
N
TRANSFORMER
12/20VA
LN
THM 4
C
RW
T T COM
L
PUMP 4
NL
PUMP 5
NL
PUMP 6
N
THM 5
C
RW
T T COM
THM 6
C
RW
T T COM
PWR
ZONE1
ZONE2
ZONE3
ZONE4
ZONE5
ZONE6
DipSwitches
Master Slave
Priority OFF Priority ON
Primary OFF Primary ON
Exercise OFF Exercise ON
Post Purge OFF Post Purge ON
6 Zone
Z6P
THM 2
C
RW
T T COM
COMMS
DP
DHW
ZR/ZC
X X
THM
3
C
RW
T T
COM
THM 1
C
RW
T T COM
L
PUMP 2
N
PRIMARY
PUMP
L
PRIORITY
PUMP 1
N
L
POWER IN
N
GROUNDS
L
PUMP 3
N
TRANSFORMER
12/20VA
LN
THM 4
C
RW
T T COM
L
PUMP 4
NL
PUMP 5
NL
PUMP 6
N
THM 5
C
RW
T T COM
THM 6
C
RW
T T COM P
WR
ZONE1
ZONE2
ZONE3
ZONE4
ZONE5
ZONE6
DipSwitches
Master Slave
Priority OFF Priority ON
Primary OFF Primary ON
Exercise OFF Exercise ON
Post Purge OFF Post Purge ON
C R Rh W1
A heat demand can also be initiated by any type
of device that has dry contacts (dry contacts are
a set of contacts that open and close but do not
have any voltage present until supplied from an
outside source). The end switch on a Z-one series
zone valve is an example of a dry contact. Using
a dry contact to connect R to W will initiate a heat
demand.
Dry Contacts
Always refer to the thermostat manufacturer’s instructions.
SAFETY INSTRUCTION
This safety alert symbol will be used in this manual to draw attention to safety
related instructions. When used, the safety alert symbol means ATTENTION!
BECOME ALERT! YOUR SAFETY IS INVOLVED! FAILURE TO FOLLOW THESE
INSTRUCTIONS MAY RESULT IN A SAFETY HAZARD.
CAUTION: All work must be performed by qualified personnel trained in the
proper application, installation, and maintenance of systems in accordance with all
applicable codes and ordinances.
CAUTION: Electrical shock hazard. Disconnect power before installation to prevent
electrical shock or equipment damage. Make sure all connections are in accordance
with the electrical wiring diagram and in accordance with national and local electrical
codes.
CAUTION: Avoid electrical noise interference. Do not install near large conductors,
electrical machinery, or welding equipment. Avoid locations where excessive
moisture, corrosive fumes, vibration, or explosive vapors are present.
Caleffi shall not be liable for damages resulting from misapplication or misuse of it products.
WARNING: NEVER CONNECT R & C DIRECTLY,
this will be a direct short on the 24 VAC supply

4
Overview
•Compatiblewith2,3and4-wirethermostatsorother
low voltage controllers with switching action
•120VACinput
•Heavyduty,sealed,DPDT,fuseprotectedrelay 
(with spare fuse)
•Twodrycontactoutputs(Relay1andRelay2)for
operating 120 VAC pump with boiler enable or two
devices without boiler enable
•5Acapacityeachrelay-10Atotal
•Rearknock-outsformountingonto4”x4”junctionbox
•Highcapacity6VAtransformer
•Simplifiedwiringwithpre-installedjumper
•100%factorytestedwith3yearwarranty
•ETLcertified
See technical brochure 01284-14 NA for more product
information.
4009064
Certified to CSA C22-2 No.24
Conforms to UL Standard 873
ZSR101 - Single Zone Switching Relay

5
When a zone has a
demand from a thermostat
(TT or R W) the relay will
close sending 120 VAC
to Relay #1 NO terminal
and switching the pump
on, and the C to NO dry
contact on relay #2 closes,
signaling the boiler of a heating demand.
1 Zone
ZSR101
C
RW
T T COM
L
POWER IN
NC
RELAY #1
NO NC C
RELAY #2
NO NC
TRANSFORMER
PWR
ZONE
1 Zone
ZSR101
C
RW
T T COM
L
POWER IN
NCRELAY #1
NO NC CRELAY #2 NO NC
TRANSFORMER
PWR
ZONE
Operating Principles
R, W, C and T T Comm dual labeling at thermostat terminals.
Compatible with low voltage 2, 3, or 4 wire thermostats or any
other low voltage devices having a switching action.
Supply 120 VAC hot to terminal L and 120 VAC neutral to N.
A factory installed jumper from L terminal to the C terminal of
Relay 1 is supplied for simplified pump connection.
Dual labeled T-stat terminals.
Compatible with 2, 3 and 4
wire T-stats.
Replaceable fuses.
6 VA Transformer.
Keyhole mounting
which fits a 4X4
junction box.
Pre-installed jumper. Rear knockout for
4X4 junction box.
If dry contacts are desired from relay #1, remove the factory
installed jumper between L and C.
Cover removal
Hold either the left or the right end
of the box up and at an angle. Use
body for stabilizing relay box. Insert
screwdriver and push tab inward.
Turn box and repeat inserting
screwdriver and pushin tab inward on
opposite side, cover should release
from base.
Slide cover off base.
Mounting: Do not mount to a
surface that exceeds 115°F (45°C).
The unit must be only located in dry
interior locations. Use only copper
conductor supply wire suitable for
at least 105° C. All circuits must
have a common disconnect and
be connected to the same pole of
the disconnect. It is not suitable for
installation in hazardous locations.
120VAC input
power connection

6
T
T
RWC
TTcom
power
zone
transformer
N LL RELAY 1
C N/O N/C C N/O N/C
RELAY 2
CalefÞ!
single zone relay
L
N
A1 - Single thermostat
Hydronic diagram is for illustration purposes only, some components have been removed for simplicity.

7
Sequence of Operation / Settings
• A demand occurs and closes RW (TT)
• Relay #1 and relay #2 both fire connecting the
common terminal to the NO terminal.
• If the factory installed jumper has not been
removed, the NO terminal of relay #1 will
deliver the hot leg of 120 VAC. Relay #2 has
dry contacts.
• The zone LED illuminates.
• The demand is satisfied and opens RW (TT).
• The relay contacts return to their normal
position (common to normally closed).
• The zone LED turns off.
Description of terminals
= Ground
N = Neutral (Common leg of 120 VAC)
L = Line (live leg of 120 VAC)
C = Common terminal
NO = Normally Open terminal
NC = Normally Closed terminal
Note: There is a factory installed jumper between the 120
VAC line (L) and the common terminal of relay #1 (C).
Thermostat terminals
R = 24 VAC
W = Heat call
C = Common of 24 VAC
WARNING: NEVER CONNECT R & C DIRECTLY,
this will be a direct short on the 24 VAC supply

8
RWC
TTcom
power
zone
transformer
N LL RELAY 1
C N/O N/C C N/O N/C
RELAY 2
CalefÞ!
single zone relay
4-wire zone valve 4-wire zone valve 4-wire zone valve
R W
24 VAC
T
T
RWRW
End switch wires
L
N
A2 - Multiple thermostats
Hydronic diagram is for illustration purposes only and could be missing system components.

9
Sequence of Operation / Settings
• There is a demand by one of the t-stats which
sends power to the corresponding zone valve.
• When the zone valve opens, its end switch
contacts close and signal a demand to the RW
(TT) contacts on the single zone relay control.
• Relay #1 and relay #2 fire
• If the factory installed jumper has not been
removed, the NO terminal of relay #1 will
deliver the hot leg of 120 VAC thus firing the
pump.
• Relay #2 closes the TT contacts on the boiler
signally a demand.
• The Zone LED illuminates.
• When the last of the T-stats is satisfied, the
corresponding zone valves closes which
opens the end switch contacts.
• The relay contacts return to their normal
position turning off power to the system pump
and opening the RW (TT) contacts.
• The Zone LED turns off.
WARNING: NEVER CONNECT R & C DIRECTLY,
this will be a direct short on the 24 VAC supply
Description of terminals
= Ground
N = Neutral (Common leg of 120 VAC)
L = Line (live leg of 120 VAC)
C = Common terminal
NO = Normally Open terminal
NC = Normally Closed terminal
Note: There is a factory installed jumper between the 120
VAC line (L) and the common terminal of relay #1 (C).
Thermostat terminals
R = 24 VAC
W = Heat call
C = Common of 24 VAC

10
buffer tank
thermostatic!
radiator valves!
(TRV) on each!
radiator
TRV
TRV
TRV
TRV
TRV TRV
RWC
TTcom
power
zone
transformer
N LL RELAY 1
C N/ON/C C N/ON/C
RELAY 2
CalefÞ!
single zone relay
T
T
L
N
A3 - Single master thermostat, panel radiators with TRVs, variable speed pump
Hydronic diagram is for illustration purposes only, some components have been removed for simplicity.

11
Sequence of Operation / Settings
• A single “master” thermostat is wired to the
ZSR101 control. The master thermostat is set
to a slightly higher set point than the desired
room temperatures on the thermostatic
radiator valves.
• When the temperature drops below the
thermostat’s set point, a heat demand is
initiated by closing the R & W terminals.
• Relay #1 and relay #2 both fire.
• If the factory installed jumper has not been
removed, the NO terminal of relay #1 will
deliver 120 VAC line to the variable speed
circulator.
• Relay #2 closes the TT contacts on the boiler
signaling a demand.
• The Zone LED illuminates.
• Using an outside air sensor and system
temperature sensor located in the buffer tank,
the boiler determines if the water in the boiler
meets the target temperature based off the
outside air reset curve.
• As long as the master thermostat is calling,
the boiler will maintain the buffer tank to the
target temperature.
• The thermostatic radiator valves modulate the
flow through the panel radiators because the
variable speed circulator is enabled.
• When the master thermostat reaches set
point, the master thermostat will open the
contact between R & W.
• The relay contacts return to their normal
position turning off power to the variable
speed circulator and opening the RW (TT)
contacts. Both the boiler and pump are
no longer enabled.
• The Zone LED turns off.
WARNING: NEVER CONNECT R & C DIRECTLY,
this will be a direct short on the 24 VAC supply
Description of terminals
= Ground
N = Neutral (Common leg of 120 VAC)
L = Line (live leg of 120 VAC)
C = Common terminal
NO = Normally Open terminal
NC = Normally Closed terminal
Note: There is a factory installed jumper between the 120
VAC line (L) and the common terminal of relay #1 (C).
Thermostat terminals
R = 24 VAC
W = Heat call
C = Common of 24 VAC

12
ZSR10X - Multi-Zone Pump Control
Overview
• Compatible with low voltage 2, 3, or 4 wire
thermostats
• R, W, C and TT Comm dual labeling at thermostat
terminals
• Z-oneLink unlimited zone expansion
• 120 VAC pump outputs
• Selectable priority with 1 hour time-out feature
• Selectable post purge and exercise
• Dry contacts for DHW (ZR/ZC), capable of switching
line voltage
• High capacity transformer
• Large terminal connections
• Simplified wiring with extra ground terminals
• Heavy duty sealed relays
• Fuse protected (with spare fuse)
• Front LED lights
• 100%Factorytestedwith3yearwarranty
• ETL approved
See technical brochure 01286-14 NA for more product
information.
4009064
Certified to CSA C22-2 No.24
Conforms to UL Standard 873