AERCO BMK 2.0 LN Natural Gas 2008 - Manual (Page 28)

CONTROL PANEL OPERATING PROCEDURES
TO AIR/FUEL
VALVE
SSOV
GAS
INLET
MANUAL
SHUT-OFF
VALVE
Figure 3-3.
SSOV Location
3. With all required safety device switches
closed, a purge cycle will be initiated and the
following events will occur:
(a) The Blower Relay energizes and turns
on Blower.
(b) The Air/Fuel Valve rotates to the full-
open purge position and closes purge
position switch. The dial on the Air/Fuel
Valve (Figure 3-4) will read 100 to
indicate that it is full-open (100%).
(c) The VFD sends a signal and turns on
the Blower.
(d) The FIRE RATE bargraph will show
100%.
4. Next, the Blower Proof Switch on the
Air/Fuel Valve (Figure 3-5) closes. The
display will show Purging and indicate the
elapsed time of the purge cycle in seconds.
The normal (default) time for the purge cycle
is 7 seconds.
100
DETAIL “A”
TO
B
L
O
W
E
R
AI
R
I
N
DIAL
(DETAIL “A”)
STEPPER
MOTOR
Figure 3-4.
Air/Fuel Valve In Purge Position
Figure 3-5.
Blower Proof Switch
3-8