TMG -HW41T Product Manual page 33

BOILER SYSTEM DIAGNOSTICS - Vacuum Switch - Optional
PROBLEM
Switch activated manually
Switch shows continuity
when activated
Switch does not shows
continuity when activated
PROBLEM
Thermostat set improperly
Boiler fires when thermostat
jumped, but will not fire with
thermostat in circuit
Boiler will not fire when
thermostat jumped
BOILER SYSTEM DIAGNOSTICS - High Temperature Limit
PROBLEM
Electrical continuity through
switch
No continuity through switch Switch bad
BOILER SYSTEM DIAGNOSTICS - Low Fuel Shut-Off
PROBLEM
Fuel level low
Fuel level proper
WW W . T M G I ND U S T R I A L . C O M
POSSIBLE CAUSE
Improper diaphragm movement
Low water flow
Air leak in or punctured
diaphragm
Problem elsewhere insystem
Switch contact bad
BOILER SYSTEM DIAGNOSTICS - Thermostat
POSSIBLE CAUSE
Thermostat set too low
Thermostat bad
Problem elsewhere insystem
POSSIBLE CAUSE
Connections loose or corroded
Problem elsewhere in system
POSSIBLE CAUSE
Switch may be operating properly Add fuel and retest.
Level sensor stuck
Reed switch bad
SOLUTION
Replace switch if improper diaphragm movement is detected.
Correct problems related to inadequate water flow.
Replace vacuum switch if diaphragm shows an air leak or
hole.
If vacuum switch works properly, continue with other boiler
control diagnostics.
Replace switch with another one.
SOLUTION
Set thermostat properly and ensure connections are not
loose or corroded.
Replace Thermostat.
Continue with boiler control diagnostics. If boiler still does not
fire, the thermostat may need
replaced.
Check connections to high temperature limit switch to ensure
that they are not loose or
corroded.
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.
Replace switch.
SOLUTION
Check level sensor for proper movement. Clear, repair, or
replace sensor assembly.
Check level sensor for proper action. Replace switch if
needed.
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SOLUTION
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