Zone
Controller
Instruction manual
• WMR-21 DPST (Double-pole/single throw)
• WMR-22 DPDT (Double-pole/double throw)
WMR-21
Switching Relay
24V
C
T
R
T
W
Made in U.S.A.
Circuit ON
WMR-22
Switching Relay
L2 L1 3
5
4
6
T
W
24V
C
NO NC
5
6
6
3
4
4
Circuit ON
T
R
120 VAC
Weil-McLain
Michigan City, IN
L2 L1
120 VAC
85902
Weil-McLain
Michigan City, IN
NO NC
Made in U.S.A.
This manual must only be used by a qualified heating installer/service
technician. Failure to comply could result in severe personal injury, death
or substantial property damage.
Part Number 550-141-859/0799
WMR Switching Relays
Contents
Hazard definitions and “To the installer” .............................................................. 2
Specifications and replacement parts ................................................................... 2
WMR-21 layout, schematic diagram and cross reference table ......................... 3
WMR-22 layout, schematic diagram and cross reference table ......................... 3
WMR-21 and WMR-22 General wiring .................................................................. 4
WMR-21 Typical application wiring ..................................................................... 4
Hazard definitions
Indicates presence of hazards that will cause severe personal injury, death
or substantial property damage.
Indicates presence of hazards that can cause severe personal injury, death
or substantial property damage.
Indicates presence of hazards that will or can cause minor personal injury
or property damage.
Indicates special instructions on installation, operation or maintenance that
are important but not related to personal injury or property damage.
To the installer
Electrical shock hazard — Disconnect power before installing or servicing.
Can cause severe personal injury, death or substantial property damage if
ignored.
To avoid severe personal injury, death or substantial property damage, never
connect the load terminals to a load that takes more current than the amount
listed for the relay in the electrical ratings.
Use copper wire only. Use of any other type of wire could cause a fire hazard
resulting in severe personal injury, death or substantial property damage.
All wiring must be installed in accordance with:
U.S.A. — National Electrical Code and any other national, state or local
code requirements. Wiring must be N.E.C. Class 1.
Canada — C.S.A. C22.1 Canadian Electrical Code Part 1 and any other
national, provincial or local code requirements. Wiring must be C.S.A.
C22.1 C.E.C. Part 1.
Specifications
Replacement parts
Weil-McLain
model
number
Transformer Switching Thermostat
voltage
action
current
amps
120 VAC
240 VAC
WMR-21
120 V 60 HZ
15 VA
DPST
.18
10 A,
¹⁄₃ HP
10 A,
¹⁄₂ HP
WMR-22
120 V 60 HZ
15 VA
DPDT
.18
10 A,
¹⁄₃ HP
10 A,
¹⁄₂ HP
Part description
Plug-in relay (24 VAC coil)
2
Single-phase motor
rating
Weil-McLain part number
510-311-021
Part Number 550-141-859/0799
Instruction manual
WMR-21 — Double pole/single throw switching relay
T/W
24V
Switching Relay
C
T
R
85903
T/R
C
Relay coil
WMR-21
T
W
4
6
3
5
Made in U.S.A.
Circuit ON
Jumper
24 VAC
120 VAC
L2
24 VAC field wiring
24 VAC factory wiring
120 VAC field wiring
120 VAC ground lead
L1
120 VAC factory wiring
WMR-21 cross reference table
L2 L1 3
5
4
6
120 VAC
Weil-McLain
Michigan City, IN
WMR-22
WeilMcLain
Argo
Honeywell Taco
WhiteRodgers
WMR-21
AR821 RA 89A
SR501 809A-189
WMR-21
AR821 RA 832A
SR501 829A-832
WMR-21
AR821 R 845A
SR501 829A-845
— Double pole/double throw switching relay
T/W
WMR-22
C
T
W
24V
C
Relay coil
Switching Relay
T
R
NO NC
5
6
85904
T/R
NO
NC
NO
NC
4
4
6
6
6
24 VAC
Circuit ON
3
24 VAC field wiring
24 VAC factory wiring
120 VAC
L2
L2 L1
120 VAC
85902
Weil-McLain
Michigan City, IN
Part Number 550-141-859/0799
5
3
4
120 VAC field wiring
L1
Jumper
120 VAC ground lead
120 VAC factory wiring
4
NO NC
Made in U.S.A.
WMR-22 cross reference table
Weil-McLain
Argo
Taco
WMR-22
AR822
SR501
3
WMR Switching Relays
WMR-21 and WMR-22
WMR-21 — Typical application
General wiring
Add circulator to L8124A or C
aquastat/relay
C
T
R
WMR-21
T
W
C
Remove factoryinstalled jumper from
L1 to 3 to use 3–4
as isolated contacts.
24 VAC
T
R
T
W
24 VAC
120 VAC
120 VAC
L2 L1 3
4
5
L2 L1 3
6
Ground
screw
Ground
Ground
Hot
Thermostat or
isolated contact
to activate relay
4
5
6
Neutral
120 VAC
85905
Hot
Normally closed
120 VAC
Normally open
Neutral
Normally open
contact out
Ground
screw
24 vac to 3-wire
thermostat
Common
All wiring must be installed in
accordance with:
U.S.A. — National Electrical
Code and any other
national, state or local code
requirements. Wiring must
be N.E.C. Class 1.
Canada — C.S.A. C22.1
Canadian Electrical Code
Part 1 and any other
national, provincial or local
code requirements. Wiring
must be C.S.A. C22.1 C.E.C.
Part 1.
WMR-21
Normally open
contact out
Electrical shock hazard —
Disconnect power before
installing or servicing. Can
cause severe personal injury,
death or substantial property
damage if ignored.
Thermostat or
isolated contact
to activate relay
24 vac to 3-wire
thermostat
Thermostat or
isolated contact
to activate relay
24 vac to 3-wire
thermostat
T
Circulator 2
T
ZR
WMR-22
T
R
T
W
C
5
6 6
NO NC
ZC
B1
To burner control
L8124A or C
Aquastat/relay
B2
C1
24 VAC
C2
Circulator 1
120 VAC
Hot
4
Normally closed
Ground
Neutral
Normally open
Ground
screw
Remove factoryinstalled jumper from
L2 L1 3 4 4 L1 to 3 to use 3/4/4
NO NC as isolated contacts.
Common
120 VAC
1
Neutral
120 VAC
2
Hot
85907
Legend
85906
120 VAC field wiring
24 VAC field wiring
120 VAC ground lead
24 VAC factory wiring
120 VAC factory wiring
Part Number 550-141-859/0799