INSTALLATION AND OPERATION INSTRUCTIONS
5-10
SL 80-399 MODULATING GAS BOILER
SL 26-260 G3, SL 40-399 G3 MODULATING GAS BOILERS
5.3.4 Temperature Problems
SYMPTOM
DIAGNOSIS
REMEDY
LOW HEAT
Operating temperature
too low.
Increase temperature target.
Priority parameters
or load configuration
improperly set up.
Review load configuration parameters.
Unit undersized.
Refer to Load Calculation vs. Boiler Output.
Air trapped within
system.
Bleed system as required.
Improper system
piping.
Refer to recommended piping in
Section 1.6
System pump
undersized.
Check pump manufacturer’s data/check temp
differential across heat exchanger.
Poor gas/air mixing.
Check CO
2
level.
Defective thermostat.
Refer to manufacturer’s instructions.
Obstruction in
condensate drain.
Inspect and clean condensate drain.
Unit cycling on
operating/ safety
controls.
Check operation with Ohmmeter/Voltmeter.
System radiation
undersized.
Check manufacturer’s rating tables for capacity per
foot.
TEMPERATURE EXCEEDS
THERMOSTAT SETTING
Incorrect anticipator
setting.
Check with Ammeter.
Thermostat not level.
Check level.
ONE OR MORE ZONES DO
NOT HEAT PROPERLY
Air trapped within
zone(s) piping
Vent system/zone as required.
Low radiation/
excessive heat loss.
Check actual length of pipe using radiation / heat loss
calculation.
Low flow rate to
zone(s).
Check temperature drop across zone.
Defective zone valve/
zone circulator.
Check operation per manufacturer’s instructions.
