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BLOCKED VENT SAFETY SWITCH
(BLOCKED VENT SAFETY SHUTOFF)
Blocked vent safety switch is manual reset disc thermostat
with fixed setpoint (340°F (171°C)), and normally closed
contacts. It is located at relief opening of integral draft diverter.
In event of chimney or venting system blockage causing
products of combustion to spill out of relief opening, blocked
vent disc heats up and blocked vent contacts open, shutting
down flow of gas to main burners by removing power to gas
valve.
In event blocked vent contacts open, reset button on back
of switch will pop up. Blocked vent safety switch must be
reset manually, after switch has cooled off, by pushing
reset button down. Check venting system and chimney for
blockage when restoring system to operating condition. DO
NOT operate boiler without Blocked vent safety switch.
ROLLOUT SWITCH
(FLAME ROLLOUT SAFETY SHUTOFF)
Rollout switch is temperature-sensitive fuse link device.
Located on boiler base just outside fire box. In event of
heat exchanger flueway blockage causing flame to roll
out of fire box, fuse does not change in appearance when
blown.
If rollout switch blows, it must be replaced with exact
replacement. Check heat exchanger flueways for blockage
when restoring system to operating condition. DO NOT
operate system without rollout switch.
17 - EQUIPMENT AND OPTIONAL ACCESSORIES