Bradford-White Corp BRUTE DELUXE BMT2V Manual De Usuario

Page 30

control switches this 24V from the input terminal to 

the stage terminal. The input for stage 1 is initiated 

by closing the circuit between the 2 terminals on the 

terminal strip labeled "input stage 1." The input for 

stage 2 is initiated by closing the circuit between the 2 

terminals on the terminal strip labeled "input stage 2."

The pump time delay relay will receive a signal 

to initiate. 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 Brute Deluxe.

Once the water flow switch makes, 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 40-second period to allow the ignitor to 

heat.

The ignition control energizes the blower. The 

blower pressurizes the air box (which supplies air to 

the burners) and closes the normally-open contact 

on the airflow pressure switch. The blocked vent 

pressure switch senses the pressure in the exhaust 

plenum. This switch opens if the pressure is excessive 

(as an indicator of a blocked vent). When these two 

pressure switches are closed, voltage is sent to the 

PSW terminal on the ignition control, which allows the 

ignition module to proceed with the ignition sequence.

If the airflow proving circuit is not proven, 

ignition module will lock out. 

Section 6.5 

describes 

the result of air flow faults in more detail.

When the ignition control gets the signal at the 

PSW terminal, it will energize its MV terminal, which 

sends power to the stage one (or on/off) main valve.

After a 7-second trial for ignition, the ignitor 

switches to flame sense mode. If a flame is not 

detected, the gas valve will close and the ignition 

module will attempt ignition again (up to two more 

times, for a total of three attempts.) If all three 

attempts fail, the ignition control will lock out.

If flame is sensed, the burner will continue to 

fire as long as there is a call for heat, and none of the 

safety circuit is interrupted.

If there is a call for stage 2 on a 2-stage unit, that 

valve will be energized.

If there is a loss of flame signal during a 

successful firing sequence, the ignition control will 

remove power from the gas valves, and then attempt 

to light up to two more times. If successful, the Brute 

Deluxe will fire normally. If unsuccessful, the ignition 

control will lock out.

When the call for heat is satisfied, the gas 

valve(s) closes, and the blower starts a 45 second post-

purge. Any pump connected to the Brute Deluxe pump 

time delay relay will continue to run for the time delay 

period (dialed by the user, 0.1 to 10 minutes).

Air flow and blocked vent status are continuously 

monitored by the Brute Deluxe ignition control, at the 

control’s PSW terminal.

At the start of an ignition sequence, if the ignition 

control sees power at PSW for 30 seconds, but the 

combustion blower has not yet been energized by the 

control (F1 and F2).  The ignition control will remain 

in this fault mode, with the blower off. If the power to 

PSW is removed while there is still a call for heat, the 

ignition sequence will start again, but the main valves 

will not be energized until PSW sees power during the 

ignition sequence.

At the start of an ignition sequence, the control 

sends the combustion blower output (F1 and F2). If 

the control does not see power at PSW for more than 

30 seconds, the control will remain in this fault mode, 

with the blower on. If proper airflow is later detected 

on PSW, the control begins a pre-purge and a normal 

trial for ignition.

If the PSW signal is lost while the Brute Deluxe 

is firing, the control will immediately de-energize the 

gas valve terminal (MV). The blower will remain on 

for the post-purge period (45 seconds), and the control 

will continue to monitor the PSW input. If the signal 

is detected during the post-purge period, a normal trial 

for ignition will begin, starting with the 15-second 

pre-purge. If the signal is not detected during the post-

purge, the control will lockout with the blower off.

*1 Difference between the temperatures at which the two switches

make R-W. Adjustable from 3°F to 10°F (1.7°C to 5.6°C) on standard

models, or from 3.6°F to 12°F (2.0°C to 6.7°C); 55°F to 175°F (13°C

to 79°C) models.

*2 Two DPDT switches operate in sequence. Each switch

differential is fixed at approximately 3°F (1.7°C) on standard models,

or 3.6°F (2.0°C); 55°F to 175°F (13°C to 79°C) models.