Burnham V7 SERIES manual Section V Boiler Cleaning, High Limit Operation, LOW Limit Operation

(Non-Burnham Drawing Copy from other Manual)

AQUASTAT SWITCHING ACTION WITHIN L8124C CONTROL

The switching action within the L8124C control has three settings:

1.high limit

2.low limit

3.adjustable differential

HIGH LIMIT OPERATION —-

The high limit opens and turns off the burner when the water temperature reaches the set point. The high limit automatically resets after the water temperature drops past the set point and through the 10°F differential.

Set the indicator at desired shutoff temperature.

LOW LIMIT OPERATION —-

On a temperature rise, with the adjustable differential at the minimum setting of 10°F, the burner circuit (R-B) breaks and the circulator circuit (R-W) makes at the low limit set point. On a temperature drop of 10°F below the set point, the R-B circuit makes and the R-W circuit breaks.

ADJUSTABLE DIFFERENTIAL —-

At any differential setting greater than 10°F, the R-B make temperature and R-W break temperature will remain the same-control setting minus 10°F. The R-B break and R- W make temperature will be the set point temperature plus the difference between the differential setting and 10°F.

EXAMPLE: Set point of 140°F; differential set at 25°F. On a temperature rise, R-B will break and R-W will make at 155°F. On a temperature fall, R-B will make and R-W will break at 130°F.

Set low limit indicator at the minimum temperature recommended for domestic hot water supply. This setting must be at least 20°F below high limit setting to prevent one switch from locking out the other.

Set the differential the desired number of degrees. 25°F differential gives longest burner cycles.

AQUASTAT SWITCHING ACTION WITHIN L8148A CONTROLS

The switching action in the L8148A control has one setting, the high limit. The switching relay is controlled by the low voltage room thermostat. On a call for heat, the relay contacts make to complete the line voltage circulator circuit and also the burner circuit if the boiler water temperature is below the high limit setting. The high limit switch shuts off the burner if boiler water temperature exceeds the high limit setting.

Set the indicator at the desired shutoff temperature.

SECTION V: BOILER CLEANING

WARNING

A ll b oiler clea nin g mus t be comp le ted w ith burn er serv ic e sw it ch turne d o ff. B oiler s

e quippe d w it h bu rner sw in g do or ha ve a pot ent ia l h azard wh ic h c an ca use s ev ere prop ert y da mage , per sona l injury or los s of lif e if ignor ed. B ef ore ope nin g s wing d oor, tu rn of f

se rvice sw it ch to boiler to prev en t a ccide nta l firing of b urne r out side the co mbus tion

c ham ber. B e s ure to t igh ten sw in g do or f ast ene r c omp let ely w he n s erv ic e is co mplete d.

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