White Rodgers 11A79-2 Setting the Control, Controls with Adjustable Stops

NOTE

All wiring should be done according to local and national electrical codes.

RED BLUE

Common

Open on rise of temperature

WHITE Close on rise of temperature

If the boiler or burner manufacturer recommends a wiring 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 top right-hand terminal (blue) has open-on- rise switch action. The bottom center terminal (white) has close-on-rise switch action.

Limit Control: When used as either a high limit control or a low limit control, use the open-on-rise terminals (red and 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.

The following wiring diagram shows a typical circuit for an oil-fired system with domestic hot water without storage tank.

Line Voltage	High
Oil Burner Control	Limit

T T 1 2 3 4

Ignition

Transformer

Burner

Motor

Combination

Low Limit-

Circulator

Control

RB

W

Circulator

Thermostat

B W Relay Type

4 3 2 1 809A-189

Hot 120V

Neutral

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

SETTING THE CONTROL

circulator operate. If boiler water temperature drops too low, the circulator will stop until the temperature rises in boiler.

1.Use a screwdriver in the adjusting slot (A) on the front 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.

“B” Fixed indicator

(cut-in point)

“F” Stop tab

“C” Differential adjusting screw

“D” Movable indicator (cut-out point)

“A” Adjusting
slot	“E” Stop screw

The movable indicator points to the temperature at which the contacts open on high limit and low limit applica- tions. On circulator applications, the movable indicator points to the temperature at which the circulator will start.

On combination low limit and circulator applications, the movable indicator points to the temperature at which the low limit will stop the burner and permit the circulator to run.

CONTROLS WITH ADJUSTABLE STOPS

1.Loosen stop screw (E) with enclosed wrench.

2.Set dial to original equipment manufacturer's specifi- cation.

3.Without moving the dial, move stop tab (F) against indicator.

4.Re-tighten stop screw (E).

!CAUTION

Setting stop higher than control being replaced could cause personal injury and/or property dam- age.

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