21
Blocked Vent Safety Shutoff
The blocked vent switch is a manual reset disc thermostat
with a fi xed setpoint (340° F), and normally closed
contacts. It is located at the relief opening of the integral
draft diverter. In the event of chimney or venting system
blockage causing products of combustion to spill out of
the relief opening, the blocked vent switch disc heats
up and the blocked vent switch contacts open, shutting
EQUIPMENT AND OPTIONAL ACCESSORIES
How A Hot-Water System Operates
Your entire heating system (boiler, piping and radiation
units) is fi lled with water. As the water in the boiler is
heated, it is pumped from the top of the boiler through
the supply main to the radiation units. The cooler water in
them fl ows back through the return main to the boiler. This
provides positive and rapid response to the thermostat.
!
WARNING
Never run water into a hot empty boiler.
Filling System With Water
Close the air vents on all radiation units. Open the valves to
these units. Make sure the boiler and expansion tank drain
cocks are closed. The air bleed screw on the expansion
tank drain fi tting should be closed. Open the valve in the
!
WARNING
FOR YOUR SAFETY READ BEFORE
OPERATING
If you do not follow these instructions exactly,
a fi re or explosion may result causing property
damage, personal injury or loss of life.
Some boilers are equipped with an
1.
intermittent ignition device which
automatically lights the pilot. Do not try to
light the pilot by hand.
Some boilers are equipped with a
2.
continuous pilot and must be manually
lighted. (See lighting instructions.) When
lighting the pilot, follow these instructions
exactly.
BEFORE OPERATING smell all around the
3.
appliance area for gas. Be sure to smell
next to the fl oor because some gas is
heavier than air and will settle on the
fl oor.
WHAT TO DO IF YOU SMELL GAS
Do not try to light any appliance.
•
Do not touch any electric switch; do not use
•
any phone in your building.
Immediately call your gas supplier from a
•
neighbor’s phone. Follow the gas supplier’s
instructions.
If you cannot reach your gas supplier, call the
•
fi re department.
Use only your hand to push in or turn the gas
4.
control knob. Never use tools. If the knob will not
push in or turn by hand, don’t try to repair it, call
a qualifi ed service technician. Force or attempted
repair may result in a fi re or explosion.
Do not use this appliance if any part has been
5.
under water. Immediately call a qualifi ed service
technician to inspect the appliance and to replace
any part of the control system and any gas
control which has been under water.
line from the boiler to the expansion tank. Open the water
inlet to your boiler and leave it open. Start with the lowest
radiation unit. Open the air vent on this unit. When all the
air has escaped and water starts to fl ow from the vent,
close it. Go to the next radiation unit, and repeat this
process. Repeat until you have covered every radiation unit
in the system (ending up at the highest unit in the system).
If your units have automatic vents, this manual venting is
unnecessary but it will speed up the proper fi lling of your
system. If your system is a closed expansion tank system,
you may leave it open to refi ll the system automatically as
needed. Check the temperature pressure gauge, NOT the
position of the hand indicating the pressure. This should be
between 10 and 15 lbs. any lowering of this movable hand
below 10 lbs. will indicate loss of water due to leakage. The
automatic fi ll valve should compensate for this. Instructions
are packaged with the valve.
STARTING THE BOILER
down the fl ow of gas to the main burners by removing
power to the gas valve. In the event that the blocked vent
switch contacts open, the reset button on the back of the
switch will pop up. The blocked vent switch must be reset
manually, after the switch has cooled off, by pushing the
reset button down. Check the venting system and chimney
for blockage when restoring the system to operating
condition. DO NOT operate the boiler without a blocked
vent switch.
