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Maintenance and Service
Safety Circuit System
Your fireplace has a safety circuit system designed
to protect you and your home from damage due to
unmanaged heat. This section outlines the safety
components, how they work, and how to test them in the
event of malfunction.
The safety system is activated after 15-20 minutes.
The safety system is integrated with the IFC ON/OFF
circuit. The burner will not operate unless the circuit is
satisfied (also a closed burner switch).
Start-up mode: Safety system is not activated yet; circuit
is in bypass mode through the timing relay (normally
closed).
Operating mode: Snap disc (normally open) will close
when it reaches operating temperature (120F); this will
send 120VAC to the cooling fan system (see below) and
timing relay.
Cooling fan system rheostat resists the input to 98-
103VAC; this is a set input and should be confiirmed
during installation via the front fan terminals. The rheostat
has a limited range of adjustment, DO NOT attempt to
adjust it lower when resistance on the knob is felt.
The timing relay switches safety system out of bypass
mode and the circuit is now dependant on the sail switch
circuit. There is a 5 second delay to allow cooling fans to
reach operating speed.
The sail switch (normally open) senses the monitored fans
are operating with optimal air flow. The flow will active
the sail paddle and close the circuit when satisfied.
Power will continue to run through the cooling fan system
with the fireplace turned off. Only when the snap disc falls
below its set temperature will the fans turn off.
Snap Disc
: Activates safety system when fireplace is
sifficiently hot.
Testing:
AB (cool): NO continuity
AB (hot 120F+): YES continuity
B
A
B
A
C D E
GROUND
A
B
C
B
C
A
A B
Timing Relay
: Switches system from bypass mode to
operating mode when powered via snap disc. There is a 5
second delay to give fans time to build speed.
Testing:
CE (no power at AB): YES continuity
CE (120VAC at AB): NO continuity
Terminal D is irrelevant
Cooling Fan Rheostat
: Resists input power to cooling
fans for optimal speed and noise reduction.
Testing:
AB: 70VAC on
lowest setting
Cooling Fan
: Draws air from the lower framing gap to
create an airwash through the inner and outer glass
barrier; the heat is released at upper framing gap.
*U50/U70 models also
use a chase fan to cool
the rear framing cavity.
Testing:
AB: 14-15 ohms is good
AB: 105-110V when running is optimal
Sail Switch
: A sail switch monitors select cooling fans to
sense proper air flow in being achieved.
Testing:
AB: NO continuity (no air flow)
AB: YES continuity (with air flow)
Terminal C is irrelevant
Breathable Framing
:
Provides the air wash
needed for the cooling
fans to do their job.
Framing must be
constructed in accordance
with this manual; failure to
do so will result in property
damage or personal injury.
Safety Circuit Components
