Bradford White BWCH Operations Instructions download pdf (Page 36)

Page 36

BRADFORD WHITE CORP.

SECTION 6.

Operating Instructions

6.1 Sequence 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

re 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 eld-wiring

terminals strip will energize a eld pump that is

properly interlocked with the Copper Brute II. The

green

PUMP indicator on the front panel will light.

Once the water ow 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 airow pressure

switch(es). This allows the ignition module to proceed

with the ignition sequence.

The blocked ue pressure switch senses the

pressure in the plenum. It will interrupt the airow

sensing circuit if this pressure exceeds a maximum

value. If airow 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 ame is detected by the

ame 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 ame is sensed, the burner will continue to

re 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 re 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 ame 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 satised, 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 satised

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 ll 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 ow 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

lled 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

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