Armstrong International
IOM-706 V2.0
Flo-Direct Water Heater
Page 26 of 45
Sequence of Operation
Note
: The description in this section assumes that the heater is in automatic mode
—
"MANUAL/OFF/AUTO" switch set to "AUTO." If heater is equipped with modulating burner,
modulation control must display red “MANUAL” when heater is not running or it may not
start.
Do not press “MANUAL” on the Powers controller thinking it must match heater's
mode!
Once heater starts, Powers controller will switch to auto mode automatically.
Text in italics below is more specific information intended to aid in troubleshooting
1
When low level float switch in remote storage tank calls for water
(Wire #11; PLC input
0 energized)
, PLC will confirm that top float switch in lower canister
(wire #20; PLC
input 8)
is not in a fault condition and burner is in low fire position
(wire #13; PLC
input 2)
, then energize control relay A
(PLC output 0 energizes wire #81; control relay
contacts close)
.
Note
: PLC is preset. Re-progamming it without written permission will void the
warranty and absolve Armstrong of all service commitments.
2
If low gas pressure, high gas pressure, and high temperature switches are all closed
(no fault conditions), power will be supplied to Veri-Flame controller
(wire #47;
terminal 7 on Veri-Flame
—
"Interlocks closed" light will come on)
. (Any fault condition
will cause Veri-Flame control to shut down heater.).
3
If air pressure switch is open and fuel valve is closed, blower will start ("BLOWER ON"
lights;
wire #48; terminal 8 on Veri-Flame
).
4
Within a few seconds, air pressure switch must indicate adequate pressure ("AIR
FLOW" lights), then blower will initiate a 30-second purge
(time is adjustable using
DIP settings on Veri-Flame)
.
5
Veri-Flame control allows fuel into burner ("FUEL ON" lights;
Veri-Flame terminals 3
and 4 energize
) and the spark rod to ignite it ("IGNITION ON" lights). Simultaneously
water valve opens ("WATER ON" lights).
6
When UV scanner confirms flame, Veri-Flame control
(wire #45; terminal 5 on Veri-
Flame)
energizes actuator:
• Non-modulating burner opens air and fuel dampers, and burner enters high-fire
setting.
• Modulating burner control changes from manual to auto mode allowing control to
track set point.
7
Veri-Flame control de-energizes spark rod ("IGNITION ON" off;
wire #44; terminal 4 on
Veri-Flame
).
8
Pump will start ("PUMP ON" lights;
wire #18; PLC input 6
) when water in lower
canister reaches second float switch.
9
During operation when correctly set, transfer pump bypass will cycle on (increasing
water flow; "BYPASS ON") and off keeping water level in lower canister between
middle float switches.
10
Once upper level switch in remote storage tank closes
(wire #16; PLC input 4)
, PLC will
de-energize CR-A causing Veri-Flame control will turn off fuel valves. Blower will run for
several seconds to purge any remaining fuel.
11
If POC switch senses that fuel valve did not close completely, lockout valve will close
and blower will come on to purge any fuel.
