Troubleshooting Guide - IBC VFC 15-150 Installation And Operating Instructions Manual

5.3.1 Using Control Module Errors Displayed
SYMPTOM
AIRFLOW ERROR
Touch Screen Message:
Error – Low Air Flow
Low combustion airflow; soft
error; will retry in 5 minutes
WARNING
Never attempt to repair
the control module (circuit
board). If the control module
is defective, replace it
immediately.
WATERFLOW ERROR
Touch Screen Message:
Error - No Water Flow
Low water flow – soft error; will
retry in 5 minutes
TROUBLESHOOTING
VFC 15-150, VFC 45-225 MODULATING GAS BOILERS

5.3 TROUBLESHOOTING GUIDE

DIAGNOSIS
Check fan operation
Check for fouled
reference lines and air
sensor
Check achieved fan
power
Water noise in vent.
Excess condensate in
venting.
Check pressure
sensors
Check for proper
piping
Check primary pump
Check for restriction
in water pipe
REMEDY
• Check lead is attached at fan.
• Cycle power off/on; listen for fan initialization.
If no action, focus your attention on the fan
itself.
• Check clear vinyl air reference lines below
gas valve for any sign of water. After
disconnecting from black sensor, blow clear.
Check for exhaust re-ingestion, or repeated
power interruptions .
• Ensure condensate trap is not blocked.
• Go to Advanced Diagnostics and check
differential air pressure sensor (at rest and
with fan on). See Section 5.2.3.
In Diagnostics, Fan Operation, during Pre-
purge, Fan Pressure (FP) should move close to
Required Pressure (RP); if FP only 480 to 600
vs. RP of 1,000 to 1,200, then check for actual
vent system blockage: (a) disconnect intake
within boiler case; (b) open burner then fan/gas
valve looking for debris.
• Check condensate trap for obstructions.
Remove obstructions and refill condensate
trap with water.
• Check vent length, size and configuration,
particularly re: horizontal 2" piping.
• Check wiring: water pressure sensors to
controller.
• Check pressure sensors. See Section 5.2.4
– 2nd paragraph.
Refer to Section 1.6 Water Piping for
recommended piping installation.
If there is a valve on the primary loop, close it
and listen for cavitation (evidence flow). If not,
go to Installer Setup; select pump purge "on" to
run pumps without a heat call - check for heat
buildup at pump body (indicates no flow).
Check temperature differential across heat
exchanger at low –medium firing rate if possible.
Examine air strainer components for scale.
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