2.3.9
Air Vent Valve
Provide with screwed connection, stainless steel disk, and stainless steel
seats to vent entrapped air.
2.3.10
High Temperature Limit Switch
**************************************************************************
NOTE: Specify alarm and indicating lights if input
exceeds 117 kW 400,000 BTU/hr.
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Provide immersible aquastat type with a temperature setting above that of
the combustion regulator and below that of the lowest relief valve setting.
Aquastat shall function to cause a safety shutdown by closing fuel
valves[,] [and] shutting down burner equipment [, activating a red
indicating light, and sounding an alarm] in the event that boiler water
temperature rises to the high temperature limit setting. A safety shutdown
due to high temperature shall require manual reset before operation can
resume and prevent recycling of burner equipment.
2.3.11
Low Water Pressure Control
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NOTE: Specify alarm and indicating lights if input
exceeds 117 kW 400,000 BTU/hr. Select operating
pressure required.
**************************************************************************
Provide mercury switch type. Control shall have a main scale, adjusting
screws at the top of the case, and have an internal or external bellows.
Control shall be the type which will open an electric circuit on a drop in
pressure below a set minimum. Control shall be set and installed to cause
a safety shutdown by closing fuel valves[,] [and] shutting down burner
equipment [, activating a red indicating light, and sounding an alarm] in
the event that water pressure in the system drops below [83 kPa (gage)] [12
psig] [_____]. A safety shutdown due to low water pressure shall require
manual reset before operation can resume and prevent recycling of burner
equipment.
2.3.12
Low Water Level Cutoff Switch
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NOTE: Specify alarm and indicating lights if input
exceeds 117 kW 400,000 BTU/hr.
**************************************************************************
Provide float actuated type. Low water level cutoff shall cause a safety
shutdown by closing fuel valves[,] [and] shutting down burner equipment [,
activating a red indicating light, and sounding an alarm] in the event that
water level drops below the lowest safe permissible water level established
by the boiler manufacturer and ASME BPVC SEC IV. A safety shutdown due to
low water shall require manual reset before operation can resume and
prevent recycling of burner equipment.
2.3.13
Boiler Safety Control Circuits
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NOTE: Include draft fan if power burner is
SECTION 15514N
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