5-11
TROUBLESHOOTING
SL 80-399 MODULATING GAS BOILER
SL 26-260 G3, SL 40-399 G3 MODULATING GAS BOILERS
5.3.5 Miscellaneous
SYMPTOM
DIAGNOSIS
REMEDY
FUMES AND HIGH HUMIDITY
Improperly installed
condensate trap
Refer to installation/operation instructions
Leak in vent piping
Inspect using soap solution
Flue gas leak within boiler
Visually inspect all mechanical connections
BOILER STUCK ON
INITIALIZE
Fan board failure
Replace fan.
TOUCHSCREEN MESSAGE:
Unknown Error
Temperature sensor input
problem.
Test each temperature sensor for appropriate
readings and Replace defective temperature
sensor.
BOILER REMAINS IN
STANDBY DURING CALL FOR
RESET HEATING OR SET-
POINT (DHW OPERATION
WORKS AS NORMAL). (5
BUTTON CONTROLLER)
Boiler may be in Warm Weather
Shut-down.
In Installer Setup / Heat Load Configuration
/ Configure Load (Heating) adjust Summer
Shutdown Temperature to a temperature above
that registered by outdoor sensor.
‘GHOST’ CALL FOR HEAT.
Triac or ‘Power-robbing’
thermostat sending current to
boiler.
Remove Therm. connections from boiler to confirm
that stray voltage, or current induced in thermostat
wiring, is source of nuisance signal. Replace the
Power Robbing thermostat, isolate the thermostat
with a relay or install a properly sized resistor
(consult the thermostat manufacturer first then IBC
for instructions).
ERROR: WATER HIGH LIMIT /
LOW WATER CUTOFF WON’T
CLEAR.
Boiler is in 1 hour safety
lockout.
Reset safety device and cycle boiler power off and
on to reset error.
DHW TAKING TOO LONG TO
HEAT.
Sensor may be under-reading
actual water temp.
Check sensor engagement; note well is 15cm /
almost 6 inches deep and sensor must be fully set
to back. Check programmed settings boiler temp
set too close to the required DHW temp
BOILER OUTPUT NOT
MODULATING UP TO
MAXIMUM DESPITE TARGET
NOT BEING REACHED.
Possible flow issue: check for
35 or 40 degree F temperature
difference between boiler
supply and return water
temperatures (evokes
electronic fence).
Confirm that primary pump is able to overcome
head loss of boiler and primary loop piping at the
required flow rate.
PRIMARY PUMP RUNS BUT
LOAD PUMPS DO NOT.
Wiring not complete.
Supply power to the PV/L and PV/N terminals
from the incoming power supply to the boiler.
(Factory wired on boilers with a factory installed
Touchscreen Controller)
PRIMARY PUMP RUNS
DURING PARALLEL-PIPED
DHW CALL.
Load definition as DHW.
Re-define DHW load as DHW Loop 2 (5 button
Controls) to turn off primary pump during domestic
hot water calls. On Touchscreen Controllers set the
boiler pump to off in the Installer Set-up Menu.
