Zone
Controller
Instruction manual
• WMR-21 DPST (Double-pole/single throw)
• WMR-22 DPDT (Double-pole/double throw)
WMR-21
24V
T
T
W
Switching Relay
C
R
Made in U.S.A.
WMR-22
Switching Relay
NO NC
6
6
24V
T
T
W
5
R
C
L2 L1
3
4
120 VAC
Weil-McLain
Michigan City, IN
L2 L1
3
4
4
NO NC
120 VAC
Made in U.S.A.
Weil-McLain
Michigan City, IN
85902
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-21 — Double pole/single throw switching relay
85903
T/W
T/R
C
WMR-21
Switching Relay
24V
T
T
W
C
R
4
3
6
Made in U.S.A.
Circuit ON
24 VAC
5
24 VAC field wiring
24 VAC factory wiring
120 VAC field wiring
120 VAC ground lead
120 VAC factory wiring
120 VAC
L2
L1
WMR-21 cross reference table
Weil-
Argo
Honeywell Taco
White-
McLain
Rodgers
L2 L1
3
4
5
6
WMR-21 AR821 RA 89A
WMR-21 AR821 RA 832A
WMR-21 AR821 R 845A
SR501 809A-189
SR501 829A-832
SR501 829A-845
120 VAC
Weil-McLain
Michigan City, IN
WMR-22 — Double pole/double throw switching relay
85904
T/W
T/R
C
WMR-22
Switching Relay
NO
NC
NO
NC
4
4
6
6
NO NC
6
6
24V
T
T
W
5
R
C
24 VAC
3
5
24 VAC field wiring
24 VAC factory wiring
120 VAC field wiring
120 VAC ground lead
120 VAC factory wiring
120 VAC
Jumper
L2
L1
L2 L1
3
4
4
WMR-22 cross reference table
NO NC
120 VAC
Weil-McLain
Argo
Taco
SR501
Made in U.S.A.
Weil-McLain
Michigan City, IN
WMR-22
AR822
85902
Part Number 550-141-859/0799
3
WMR-21 and WMR-22
WMR-21 — Typical application
General wiring
Add circulator to L8124A or C
aquastat/relay
24 vac to 3-wire
thermostat
Thermostat or
isolated contact
to activate relay
24 vac to 3-wire
thermostat
Thermostat or
isolated contact
to activate relay
Electrical shock hazard —
Disconnect power before
installing or servicing. Can
cause severe personal injury,
death or substantial property
damage if ignored.
WMR-21
WMR-21
T
R
T
W
T
R
T
W
C
C
Remove factory-
24 VAC
24 VAC
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
installed jumper from
L1 to 3 to use 3–4
as isolated contacts.
120 VAC
120 VAC
L2 L1
3
4
5
6
L2 L1
3
4
5
6
Ground
screw
Ground
screw
Ground
Neutral
Ground
Neutral
120 VAC
Hot
120 VAC
Hot
85905
national, provincial or local
code requirements. Wiring
must be C.S.A. C22.1 C.E.C.
Part 1.
Thermostat or
isolated contact
to activate relay
Circulator 2
T
T
ZR
ZC
B1
B2
C1
C2
1
WMR-22
T
R
T
C
5
6
6
W
NO NC
L8124A or C
Aquastat/relay
To burner control
Circulator 1
24 VAC
Neutral
120 VAC
Hot
120 VAC
Remove factory-
installed jumper from
L1 to 3 to use 3/4/4
as isolated contacts.
2
L2 L1
3
4
4
Ground
screw
85907
NO NC
Ground
Neutral
120 VAC field wiring
120 VAC ground lead
120 VAC factory wiring
Legend
24 VAC field wiring
120 VAC
Hot
24 VAC factory wiring
85906
Part Number 550-141-859/0799
4
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