Manual

SEQUENCE OF OPERATIONS

BOILER LESS TANKLESS COIL:

Aquastat hiqh limit controller:

The aquastat control's high limit contacts open and turn off the burner when the boiler water

temperature reaches the control's high limit set point. The high limit contacts automatically reset after

the boiler water temperature drops past the set point by IO°F, which is a fixed differential.

INTERNAL WIRING FOR HONEYWELLAQUASTAT L8148A

LENE VOLTAGE

CLA.. S II,

24 VOLTS

JUMPER5__

IK2

When the thermostat controls call for domestic space heating. The sequence of operation for

the burner and circulator is as follows:

1. Thermostat calls for heat, completing circuit between terminals T & T on the aquastat controller,

energizing the 1K relay coil.

2. With the 1K relay coil energized, contacts 1K1 and 1K2 are closed. Terminals C1 and C2 are

energized providing power to the circulator. Terminal B1 is energized, providing power to the oil

burner primary control. This, in turn, powers the ignition coil and burner motor.

3. With the primary control energized, the burner operation starts and remains running as tong as the

cad cell senses flame. In the event of flame failure or the flame is not fully proven within the trial for

ignition period, the primary control wilt lockout and open the burner circuit. This will require a manual

startup of the burner.

4. As long as flame is proven through the cad cell relay, the burner will remain on until the circuit is

interrupted by the boiler water temperature reaching the aquastat's high limit setting (opening high

limit contacts BR), or the thermostat is satisfied breaking the T-T circuit.

5. If the boiler water temperature reaches the aquastat's high limit setting, the high limit contact BR is

de-energized turning the burner off. However, the circulator pump will continue to run, as long as, the

thermostat calls for heat.

6. After the high limit contact BR is de-energized, the boiler water temperature must fall 10°F below the

aquastat's high limit setting for the high limit contacts BR to close and energize the burner.

When the thermostat is satisfied, the call for domestic space heating is ended. Relay coil 1K is de-

energized, opening 1K1 and 1K2 contacts. Both the burner and circulator pump operation stop.