White Rodgers 11A79-2 User manual

Printed in U.S.A. PART NO. 37-1022B
Replaces 37-1022-A
9520
FAILURE TO READ AND FOLLOW ALL INSTRUCTIONS CAREFULLY
BEFORE INSTALLING OR OPERATING THIS CONTROL COULD CAUSE
PERSONAL INJURY AND/OR PROPERTY DAMAGE.
DESCRIPTION
Operator: Save these instructions for future use!
R
WHITE-RODGERS DIVISION
EMERSON ELECTRIC CO.
9797 REAVIS ROAD
ST. LOUIS, MISSOURI 63123-5398
INSTALLATION INSTRUCTIONS
11A79-2
Direct Immersion
Hot Water Control
WHITE-RODGERS
This control is designed for use on hot water heating
systems.
It has a coiled element that is immersed directly into the
boiler water. This feature gives an unusual speed of
response to rapid changes of water temperature thereby
preventing thermal lag.
This control has single-pole, double-throw switch action,
offeringterminalsthathaveopen-on-riseswitchactionas
well as close-on-rise switch action. It may be used as a
highlimit control,low limitcontrol, circulatorcontrol, oras
a combination low limit and circulator control.
PRECAUTIONS
Shutoffmaingastoheatingsystemuntilinstalla-
tion is complete.
Label all wires prior to disconnection when ser-
vicingcontrols.Wiringerrorscancauseimproper
and dangerous operation.
Following installation or replacement, follow ap-
pliance manufacturer's recommended installa-
tion and/or service instructions to insure proper
operation.
Do not use on circuits exceeding specified volt-
age.Highervoltagewilldamagecontrolandcould
cause shock or fire hazard.
CAUTION
!
CAUTION
!
THIS CONTROL MUST BE INSTALLED BY A QUALI-
FIED INSTALLER.
Do not exceed the specification ratings.
All wiring must conform to local and national electrical
codes and ordinances.
This control is a precision instrument, and should be
handled carefully. Rough handling or distorting compo-
nents could cause the control to malfunction.
Thiscontrolhasbeenaccuratelycalibratedatthefactory.
Any attempt to calibrate this control will void the White-
Rodgers warranty.
To prevent electrical shock and/or equipment
damage, disconnect electric power to system at
main fuse or circuit breaker box until installation
is complete.
WARNING
!
INSTALLATION
When used as a circulator control, it may be located
near the boiler outlet or riser.
When used as a combination low limit and circulator
control, it should be located the same as suggested for
low limit service.
Whentighteningthecontrolintotheboiler,careshouldbe
taken to apply all leverage to the hexagonal nut only to
avoid damage to the diaphragm or control mechanism.
Iftheboilermanufacturerrecommendsacontrollocation,
follow such recommendations. If none is offered, the
following information gives suggested locations.
For high limit service, the control should be located in
thehottestpartoftheboiler.Thisisusuallyatthetopofthe
boiler. A high limit control should not be located in the
sectionoftheboilerthatcontainstheheatexchangerthat
supplies domestic hot water.
Forlowlimitoroperatingservice,thecontrolshouldbe
located so that it responds to the temperature of the
section of the boiler that heats domestic hot water.

2
“B” Fixed indicator
(cut-in point)
“C” Differential adjusting
screw
“D” Movable indicator
(cut-out point)
“A” Adjusting
slot “E” Stop screw
“F” Stop tab
BLUE
RED
WHITE
Common Open on rise
of temperature
Close on rise
of temperature
All wiring should be done according to local and
national electrical codes.
Ifthe boilerorburnermanufacturerrecommendsawiring
diagram, then follow such recommendations. If none are
offered, the instruction sheet for the primary control (gas
valve or oil burner control) may offer some suggested
circuits.
This control has a single-pole, double-throw snap action
switch. The top left-hand terminal (red) is the common
terminal.The topright-hand terminal(blue)hasopen-on-
riseswitchaction. Thebottomcenterterminal(white)has
close-on-rise switch action.
LimitControl: Whenusedaseitherahighlimitcontrolor
alowlimitcontrol,usetheopen-on-riseterminals(redand
blue).
Circulator Control: When used as a circulator control,
use the close-on-rise terminals (red and white).
Combination Low Limit and Circulator Control: For
this application, all three terminals are used.
Thefollowingwiringdiagramshowsatypicalcircuitforan
oil-fired system with domestic hot water without storage
tank.
NOTE
The low limit side of the low limit/circulator control main-
tains domestic hot water temperature all year around.
When the room thermostat calls for heat, the burner and
circulator operate. If boiler water temperature drops too
low, the circulator will stop until the temperature rises in
boiler.
SETTING THE CONTROL CONTROLS WITH ADJUSTABLE STOPS
1. Loosen stop screw (E) with enclosed wrench.
2. Setdialto original equipmentmanufacturer's specifi-
cation.
3. Without moving the dial, move stop tab (F) against
indicator.
4. Re-tighten stop screw (E).
Setting stop higher than control being replaced
couldcausepersonalinjuryand/orpropertydam-
age.
1. Useascrewdriverintheadjustingslot(A)onthefront
of the control to turn the dial so the fixed indicator (B)
points to the lowest temperature of the cycle.
2. Turn the differential adjusting screw (C) until the
movable indicator (D) points to the highest tempera-
ture of the cycle.
Themovableindicator pointsto thetemperature atwhich
the contacts open on high limit and low limit applica-
tions.Oncirculatorapplications,themovableindicator
pointstothe temperatureat which thecirculator willstart.
Oncombinationlowlimitandcirculatorapplications,
the movable indicator points to the temperature at which
the low limit will stop the burner and permit the circulator
to run.
CAUTION
!
Thermostat
High
Limit
Burner
Motor
Line Voltage
Oil Burner Control
Combination
Low Limit-
Circulator
Control
Circulator
Relay
Type
809A-189
Ignition
Transformer
12
TT4
343
B
B
RW
W1
2
Hot
Neutral
120V