60
IF YOUR SYSTEM IS NOT HEATING OR NOT GIVING ENOUGH HEAT . . .
POSSIBLE CAUSE
WHAT TO DO
Thermostat is not set correctly
Reset thermostat
Burner is not operating properly
Adjust burner per instructions.
No electric power to boiler
Check over-current protection. Check to be sure electric power supply cir-
cuit is “ON”. There may be as many as 3 safety shut-off switches installed.
Look for a red plate which may be on the service switch.
Controls out of adjustment
Reset according to instructions.
Circulating pump not running
Check over-current protection. Check relay operation. Check power to
circulator.
Poor electrical contact
Check all control terminals and wire joints.
Chimney flue is blocked
Have the chimney professionally cleaned.
RELIEF VALVE LEAKING . . .
POSSIBLE CAUSE
WHAT TO DO
Corrosion and/or deposits on
seat.
Open valve manually. Allow water to run and clear valve seat.
Water logged expansion tank
Drain tank, follow instructions to provide air buffer.
HAVE YOUR SERVICE TECHNICIAN CHECK ANY PROBLEM YOU ARE UNABLE TO CORRECT.
LIMIT CONTROL TROUBLESHOOTING GUIDE
System Condition Diagnostic Condition Check
Action
Boiler is cold,
house is cold.
Display off
120 VAC system power
Turn system power on
Display on
24 VAC T-T
No 24 V; replace control
24 V present; disconnect
thermostat, short T-T
Boiler starts, check wiring and thermostat
120 VAC at B1-B2
• If no, replace
• If yes, check burner and wiring
Low Water status light
•
If illuminated, find and repair water
leak(s).
Boiler is hot,
house is cold.
Display on
120 VAC at C1-C2
•
120 vac at C1-C2, check wiring to
pump
• Wiring OK, is pump running?
• If not, replace pump.
• If pump is running, check for trapped
air or closed zone valves.
Burner will not
turn off.
Display On
Burner wired incorrectly. L1
(black) and Limit (red) are
reversed. See wiring diagram
for installed burner.
Re-Wire burner.
20 - TROUBLESHOOTING
PN 240013415 REV A [08/15/2021]
