Bradford-White Corp BWCV Operating Instructions, Sequence of Operation, Filling the Boiler System

Page 36 BRADFORD WHITE CORP.

SECTION 6.

Operating Instructions

6.1Sequence of Operation

A call for heat can be initiated either

automatically (auto mode) under thermostatic control by the Copper Brute II temperature control, or by an external contact closure (manual mode).

In auto mode, the Copper Brute II burner will fire its stages of input to maintain a target temperature programmed into the temperature control. The controller can be programmed per Section 6.3.

In manual mode, an external control will control the Copper Brute II stages, as long as the Copper Brute II control is set to mode 6, and the auto/manual switch (located inside the control compartment) is set to manual.

The amber READY light on the front panel indicates that the control system is energized. Upon a call for heat, the green HEAT indicator on the front panel will light.

If the unit is pump-mounted, the pump will be energized. The pump terminals on the field-wiring terminals strip will energize a field pump that is properly interlocked with the Copper Brute II. The green PUMP indicator on the front panel will light.

Once the water flow switch makes, and if all of the safety interlocks are closed, the ignition module will energize the blower(s) for a 15-second pre-purge, followed by a 20-second period to allow the ignitor to heat.

Energizing the blower pressurizes the air box (which supplies air to the burners) and closes the normally-open contact(s) of the airflow pressure switch(es). This allows the ignition module to proceed with the ignition sequence.

The blocked flue pressure switch senses the pressure in the plenum. It will interrupt the airflow sensing circuit if this pressure exceeds a maximum value. If airflow is not proven, the ignition module will lockout.

The ignition module checks that the ignitor current has reached a minimum value and energizes the gas valve at the end of the ignitor heating period. The green STAGE 1 indicator on the front panel will light, indicating that the stage 1 gas valve is open.

After a 4-second trial for ignition, the ignitor switches off, and unless a flame is detected by the flame sensor, the gas valve will close and the ignition module will either attempt ignition again (up to three times) or will lockout (if the optional lockout ignition module is used).

If flame is sensed, the burner will continue to fire as long as there is a call for heat. In Auto mode, additional stages are delayed by a minimum of 60 seconds (less prepurge and ignitor warm-up time) and once energized, must fire for at least 30 seconds. The request for additional stages is indicated on the control

display, and the energizing of additional burner stages is indicated by front panel lights.

If there is a subsequent loss of flame signal, the burner will attempt re-ignition up to three times (only once if optional lockout ignition module is used.)

When the call for heat is satisfied, the gas valve(s) closes and the blower(s) continues to run for 30 seconds. The pump will continue to run for a minimum of 20 seconds and up to a programmable maximum of 10 minutes.

If a call for heat is prevented from being satisfied either by a safety interlock or due to an ignition lockout, the red SERVICE indicator on the front panel will light. To reset the standard ignition module,

the reset button on the module must be pressed. Interrupting power to this module will not reset the lockout.

The Copper Brute II 1000–2000 models have two ignition modules that control different burners. If one module should fail for any reason, the remaining

module can operate its burner(s) independently.

6.2 Filling the Boiler System

1.Ensure the system is fully connected. Close all bleeding devices and open make-up water valve. Allow system to fill slowly.

2.If make-up water pump is employed, adjust pressure switch on pumping system to provide a minimum of 12 psi (81.8 kPa) at the highest point in the heating loop.

3.If a water pressure regulator is provided on the make-up water line, adjust the pressure regulator to provide at least 12 psi (81.8 kPa) at the highest point in the heating loop.

4.Open bleeding devices on all radiation units at the high points in the piping throughout the system, unless automatic air bleeders are provided at such points.

5.Run system circulating pump for a minimum of 30 minutes with the boiler shut off.

6.Open all strainers in the circulating system, check flow switch operation, and check for debris. If debris is present, clean out to ensure proper circulation.

7.Recheck all air bleeders as described in Step 4.

8.Check liquid level in expansion tank. With the system full of water and under normal operating pressure, the level of water in the expansion tank should not exceed ¼ of the total, with the balance filled with air.

9.Start up boiler according to the procedure in this manual. Operate the entire system, including the pump, boiler, and radiation units for one (1) hour.

10.Recheck the water level in the expansion tank. If the water level exceeds ¼ of the volume of the expansion tank, open the tank drain, and drain to that level.

11.Shut down the entire system and vent all