Cycling Issues - IBC EX Series Installation & Operating Manual

8.4.4 Cycling issues

Issue
Rapid Improper values entered via
Cycling 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.
Low water flow due to improper
piping.
Low water flow due to undersized
pump.
Low water flow due to restrictions
in water pipe.
Low radiation.
Appliance over-fired.
Appliance Oversized.
Improperly set or defective
operating/safety controls.
Cycling issues
Diagnosis
Check load maximum temps are above target
temps, by ½ 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.
Check operation. Refer to manufacturer's
instructions. Check setting with ammeter.
Bleed/purge system as required. Confirm
adequate pump size and temp rise in the heat
exchanger.
Check that CO
Check pressure drop.
Refer to recommended piping for the
respective boiler model.
Check manufacturer's rating charts/check
temperature differential across heat
exchanger.
Check temperature differential across
zone/heat exchanger.
Check actual amount of radiation per zone and
refer to manufacturer's rating tables.
Clock gas meter/check gas pressure with
manometer/ check CO
Check load calculation vs. minimum boiler
output.
Check operation with ohmmeter/voltmeter.
118
Section: Troubleshooting
Fix
level is within specification.
2
level.
2