Dunkirk 90-50 Installation, Operation & Maintenance Manual page 37

After pre purge, Lamp B goes out and Lamp C illuminates, in-
dicating the hot surface igniter is powered for the 20 second
igniter warm-up period. The bright yellow orange glow of the
hot surface igniter can be observed through the observation
port in the front boiler section just above the igniter.
After igniter warm-up, the gas valve is energized, and opens
on the normal firing rate regulator (2.5" w.c.) for a 6 second trial
for ignition. Lamp D illuminates. The blue orange glow of the
burner can be seen through the observation port.
Two seconds later, Lamp C goes out as power is turned off to the
hot surface igniter. During the last two seconds of the 6 seconds
trial for ignition, main burner flames is proven by flame rectifica-
tion through the hot surface igniter, providing flame rectification
to the integrated boiler control and fully illuminating Lamp E. The
gas valve remains energized, and the boiler runs.
Thermostat ends call for heat, de-energizing gas valve and
system circulator. Burner stops firing, and Lamp D goes out.
Draft inducers remains powered. Lamp B illuminates, indicating
draft inducer is running for 30 second post-purge.
After 30 seconds, draft inducer is de-energized. Lamp B goes
out. Boiler stands by for next call for heat.
First couple of cold starts may be rough due
to gas line not being completely purged of
air, causing low firing rate and high excess air
levels.
inspect Venting and air intake system
Operate the boiler and verify that all vent/air intake connections
are gas-tight and watertight. Repair any leaks immediately.
inspect Condensate drain
Verify that all connections are watertight, and that condensate flows
freely. Repair any leaks immediately.
CHeCk ouT proCedure and adjusTmenT
SEQUENCE OF OPERATION
NOTICE
"DIAGNOSTIC INDICATOR LAMPS"
inspect system piping
Verify that all connections are watertight. Repair any leaks
immediately.
Test ignition system safety shutoff device
Turn off manual gas valve
1.
Set thermostat to call for heat
2.
Boiler begins normal sequence of operation
3.
After approximately 40 seconds (pre purge and igniter warm-
4.
up period), lamp D illuminates, indicating gas valve is powered
After 6 seconds, gas valve closes, lamp D goes out as integrated
5.
boiler control senses that flame is not present
To restart system, follow operating instructions under "START-
6.
UP PLACE IN OPERATION"
37
A. 
B. 
C. 
D. 
E. 
A. 
B. 
C. 
D. 
E. 
A. 
B. 
C. 
D. 
E. 
A. 
B. 
C. 
D. 
E. 
A. 
B. 
C. 
D. 
E. 