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BOILER SYSTEMS AND OPERATION

CONTROLLER MANUAL – SFC/SFB SERIES BOILERS

The SF series units include a factory installed and pre-wired pump. The pump

may not be able to supply adequate ow for the heat emitter circuits. A system

heating pump switched through a separate relay or control box may be needed.

SEQUENCE OF OPERATION

The boiler operates in a similar way for both a space heating and a domestic hot

water call for heat. When the boiler is powered up the controller enters a self-

diagnostic mode, and displays “2” in the Service Display.

The Sequence of Operation is as follows:

1. The boiler receives a call for heat from closing terminals X13.1 and X13.2

(24 volts section). The boiler can also receive a call from Domestic Hot Water

heating from the internal ow sensor, or from a 10KΩ sensor or aquastat

(X13.4 and X13.5 in 24V terminal).

2. The boiler does a safety check and energizes the fan for a pre-purge

(Service Display = 3).

3. Once the 5-second pre-purge is compete, the boiler enters a 5-second trial

for ignition (Service Display = 4). If the boiler fails to ignite, the boiler will

complete a 5-second inter-purge then another 5-second trial for ignition. This

is repeated 4 times before a hard lock-out occurs. The Return button must be

pressed to reset the controller and to allow for another attempt.

4. Once the burner is lit and ame has been proven the boiler operates as it is

programmed (Service Display = for Space Heating or for Domestic

Hot Water).

5. If the boiler reaches its target temperature and there is still a call for heat

or hot water the Burner will turn off (integral pump runs unless call is on-

demand dhw ). (Service Display = 1)

6. After the call for heat is satised, the boiler pump will operate for an

adjustable amount of time (Service Display = 0).

7. If the burner is on to maintain the heat exchanger temperature for DHW

Comfort mode or for Freeze Protection mode (Service Display = 7).

8. If the burner is on to maintain the heat exchanger temperature for DHW

Comfort mode or for Freeze Protection mode (Service Display = 7).

IBC SFC User Manual

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