PEERLESS PUREFIRE PFW-199, Installation, Operation & Maintenance Manual

Page: 34 / 81

A. IGNITION SEQUENCE
Figure 8.1 show the ignition sequence for the PureFire
boiler control. Table 8.1 describes each step in the
sequence in detail. The boiler control provides dual
sensing of the flame to maximize the reliability. The
control senses the burner flame with both the flame
sensor and the ignition electrode.
32
BOILER CONTROL: INTERNAL WIRING & OPERATION
8. BOILER CONTROL: INTERNAL
WIRING & OPERATION
Figure 8.1: Ignition Cycle – Graphical Representation
Off
State
Off
On
Off
On
On
On
Off
On
Ignition
Low
Off
Pump
Gas Valve
Ignitor
Flame Signal
Pr
e-
Pur
g
e
Standby
Fan
Igntion Cycle
Demand
Pr
e-
Ignition
Ignition
Pump Pos
t
Pur
g
e
Safety On/Off
Pos
t Pur
g
e 1
Pos
t Pur
g
e 2
Burner O
n
Off
High
2 s
e
c
o
nds
4 s
e
c
o
nds
2 s
e
c
o
nds
Maximum 24 hours
30 s
e
c
o
nds
minimum
Depends
on
boiler
s
e
ttings
320 milliseconds
5 s
e
c
o
nds
1
0
se
co
n
d
s
max
imum
Table 8.1: Ignition Sequence
Period Demand Status User Interface Display
Standby
No demand is present.
If the power is on to the boiler and there is no heat demand, the user interface will display “Standby” and show the boiler supply
temperature in the lower right corner. The time, in 24 hour format, is shown in the upper right. When a heat demand (either CH
or DHW) is present, the boiler begins the ignition cycle.
Pre Purge
A DWH demand must be present to initiate ignition.
Once initiated the boiler will light.
When a demand is present, the control starts the combustion air fan. The fan speed then increases to ignition speed and the user
interface displays “DOMESTIC HOT WATER” along with “Trial for ignition.” This screen is displayed until the burner is lit and
stable or until a fault occurs. Once the ignition sequence begins it will continue through ignition even if the demand has ended.