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SYMPTOM POSSIBLE CAUSE
Boiler is cold. No Power.
L7148F Aquastat Control malfunction
when used with vent damper.
L7148F Aquastat Control in reset
mode.
L7148F Aquastat Control high limit
switch shuts off the boiler before the
water temperature reaches the high
limit setting.
Boiler is too hot
Defective Thermostat or thermostat
wiring.
Defective transformer.
Defective Ignition module.
Vent damper is not connected.
L7148F Aquastat Control detects an
error.
Incorrect sensor location.
L7148F Aquastat Control temperature
setting is below the desired
temperature.
Defective sensor.
Defective L7148F Aquastat Control.
Incorrect temperature setting.
Sensor not fully inserted into well.
Defective L7148F Aquastat Control.
ACTION
Check for 120V at LIX, L2X
Check all wiring and cable
connections.
Check the circuit breaker or fuse and,
if necessary r reset or replace.
Short the W, R terminals on the
L7148F Aquastat Control. If the
system starts, check the thermostat
and low voltage wiring.
Check for 24V at R, C. If no voltage,
replace the transformer.
Check for 24V at the ignition system
and vent damper and check all wiring
connections. If voltage is present at
the ignition system, replace the
ignition system. If no voltage is
present at the ignition system, but 24V
is present at the vent damper, replace
the vent damper.
Verify proper connection at the vent
damper and L7148F Aquastat control.
Verify proper Sensor connections at
the immersion well and L7148F
Aquastat Control.
Check if the boiler water temperature
is below the limit setting.
NOTE: The L7148F Aquastat Control
may remain in reset mode 30 minutes
after the error condition is corrected.
To reset immediately, remove power,
and then restore power.
Follow the boiler manufacturer
recommendations for proper location.
Reset the potentiometer to the correct
temperature.
Check for shorted or open sensor
and/or leads.
Temporarily replace existing sensor
with new sensor. If system starts,
replace the sensor.
Replace the L7148F Aquastat Control.
Adjust the potentiometer to the proper
temperature setting.
Reinsert the sensor fully into the well.
Replace the L7148F Aquastat Control.
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