IBC Technologies SL 20-115 Installation And Operating Instructions Manual page 66

SYMPTOM
bOILER WILL NOT ATTEMPT
TO IGNITE. FAN AND PUMP
ARE OPERATING NORMALLY.
bOILER WILL NOT ATTEMPT
TO IGNITE. FAN AND / OR
PUMP ARE OFF DISPLAY
NOT ILLUMINATED
5.3.3 Cycling Problems
SYMPTOM
RAPID CYCLING
5-8
SL 20-115 MODULATING GAS BOILER
DIAGNOSIS
No power to ignition
control module.
Igniter probe/flame
sensor disconnected.
Defective Control
Module.
No power to boiler.
Defective transformer.
DIAGNOSIS
Improper values
entered via keypad.
Excess Condensate in
venting.
Obstruction in
condensate trap.
Improper vent length
or improper slope to
vent.
Incorrect settings or
defective thermostat.
Air in system or
marginal water flow.
Slow combustion air
blower.
Dirty burner/heat
exchanger.
Insufficient water
flow due to improper
piping.
REMEDY
•
Check system wiring.
•
Check air reference tubing.
reconnect probe.
Check ignition output from control module.
Check line voltage .
Check transformer. reconnect or replace as
needed.
REMEDY
Check load maximum temps are above target
temps, by 1/2 of the selected boiler differential.
ensure boiler differential is oK (16-30°F is
generally adequate)
Check venting slopes on horizontal runs. look
for sags.
inspect and clean condensate trap.
Check venting. Compare vent length and
diameter to Table 3: Maximum Venting.
Check operation. refer to manufacturer's
instructions. Check setting with ammeter.
Bleed/purge system as required. Confirm
adequate pump size and temp rise in HX
Check that CO2 level is within specification.
Check pressure drop.
refer to recommended piping in Section 1.6
INSTALLATION AND OPERATION INSTRUCTIONS