BOILER SYSTEM DIAGNOSTICS - Flow Switch - Optional
PROBLEM
POSSIBLE CAUSE
SOLUTION
Reed switch activates when
tested with external magnet
Magnet fouled and will not move
If magnet does not move freely within its housing, remove debris to unstick it.
Reed switch misadjusted
To adjust it for the flow the system is producing, loosen the reed switch and move it in its
Magnet is bad
If reed switch activated the boiler when tested with a hand held magnet, the internal magnet may
Reed switch does not
activate when tested with
external magnet
Reed switch is bad
If reed switch does not activated the boiler when tested with a hand held magnet, the reed
switch may need replacement.
Problem elsewhere in system
See diagnostics listed above.
BOILER SYSTEM DIAGNOSTICS - Thermostat
PROBLEM
POSSIBLE CAUSE
SOLUTION
Thermostat set improperly
Thermostat set too low
Set thermostat properly and ensure connections are not loose or corroded.
Boiler fires when thermostat
jumped, but will not fire with
thermostat in circuit
Thermostat bad
Replace Thermostat.
Boiler will not fire when
thermostat jumped
Problem elsewhere in system
Continue with boiler control diagnostics. If boiler still does not fire, the thermostat may need
replaced.
BOILER SYSTEM DIAGNOSTICS - High Temperature Limit
PROBLEM
POSSIBLE CAUSE
SOLUTION
Electrical continuity through
switch
Connections loose or corroded
Check connections to high temperature limit switch to ensure that they are not loose or
corroded.
Problem elsewhere in system
If there is continuity through the switch but the boiler still does not fire, there is a problem
elsewhere in the system. Continue with boiler control diagnostics.
No continuity through switch Switch bad
Replace switch.
BOILER SYSTEM DIAGNOSTICS - Low Fuel Shut-Off
PROBLEM
POSSIBLE CAUSE
SOLUTION
Fuel level low
Switch may be operating properly
Add fuel and retest.
Fuel level proper
Level sensor stuck
Check level sensor for proper movement. Clear, repair, or replace sensor assembly.
Reed switch bad
Check level sensor for proper action. Replace switch if needed.
