INSTALLATION AND OPERATION INSTRUCTIONS
5-6
VFC 15-150 - VFC 45-225 MODULATING GAS BOILERS
5.3 trouBlesHooting guide
SYMPTOM
DIAGNOSIS
REMEDY
AIRFLOW ERROR
LCD Screen Message:
Error – Insufficient Air Flow -
Check Venting
Insufficient combustion airflow;
soft error; will retry in 5 minutes
Check fan operation
• 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 for fouled
reference lines and air
sensor
• 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
.
Check achieved fan
power
in advanced diagnostics, during Pre-purge, Fan
Pressure (FP) should move close to required
Pressure (rP); if FP only 120-150 vs. rP of
250 or 300, then check for actual vent system
blockage: (a) disconnect intake within boiler
case; (b) open burner then fan/gas valve looking
for debris.
Water noise in vent.
Excess condensate in
venting.
• Check condensate trap for obstructions.
Remove obstructions and refill condensate
trap with water.
• Check vent length, size and configuration,
particularly re: horizontal 2" piping.
WATERFLOW ERROR
LCD Screen Message:
Error - No Water Flow
Low water flow – soft error; will
retry in 5 minutes
Check pressure
sensors
• Check wiring: water pressure sensors to
controller.
• Check pressure sensors. See
Section 5.2.4
– 2nd paragraph.
Check for proper
piping
refer to
Section 1.6 Water Piping
for
recommended piping installation.
Check primary pump
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 for restriction
in water pipe
Check temperature differential across heat
exchanger at low –medium firing rate if possible.
examine air strainer components for scale.
WARNING
Never attempt to repair
the control module (circuit
board). If the control module
is defective, replace it
immediately.
5.3.1 Using Control Module Errors Displayed
Summary of Contents for VFC 15-150
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