Watts LF174A - Manual

ASME Water Pressure Relief Valves
For Pressure Protection of Hot
Water Heating Boilers
Sizes:
3 ⁄
4
" – 2" (20 - 50mm)
Series LF174A
Lead Free* cast copper silicon alloy body safety relief valves for
pressure protection only of all types of hot water heating boiler
equipment. Pressure range 50 to 150psi (3 - 10 bar) with cor-
responding high ratings from 950,000 to 14,370,000 BTU/hr.
Female inlet and outlet connections. Sizes 3 ⁄
4
" - 2" (20 - 50mm).
The LF174A features Lead Free* construction to comply with
Lead Free* installation requirements.
Features
• Seat located above drain; water cannot be trapped and
sediment cannot foul seat.
• Non-mechanical seat-to-disc alignment will not stick
or freeze.
• Water seal of high temperature resisting material isolates
spring working parts from water during relief.
Specifications
Boiler Relief Valves
An ASME Section IV certified pressure relief valve shall be
installed on each boiler as noted. The valve shall have a BTU
rating in excess of the BTU rating of the boiler’s heating output.
Each hot water space heating boiler shall be equipped with a
pressure relief valve set to relieve below the maximum boiler
working pressure. The valve shall feature a raised seat and
non-mechanical disc alignment. Working parts and spring shall
be isolated from any discharge by a high temperature resis-
tant material. The valve shall be constructed using Lead Free*
cast copper silicon alloy material. Lead Free* boiler relief valve
shall comply with state codes and standards where applicable,
requiring reduced lead content. Valve shall be a Watts Series
LF174A.
Operation
As thermal expansion conditions develop, pressure builds up to
the setting of the relief valve. This will cause discharging of small
quantity of water.
Should operating controls fail, permitting runaway firing, the
boiler water may reach steam temperatures. The valve will then
open to discharge steam at the rate or faster than the boiler can
generate it, thus restoring system pressure to a safer level.
The discharge line must be the same size as the valve outlet,
and must pitch downward from the valve to a safe place for
disposal.
Valve lever must be tripped at least once a year to ensure that
waterways are clear. This device is designed for emergency
safety relief and shall not be used as an operating control.
For Hot Water Boiler Applications
ES-LF174A
Job Name ––––––––––––––––––––––––––––––––––––––––––– Contractor ––––––––––––––––––––––––––––––––––––––––––––
Job Location ––––––––––––––––––––––––––––––––––––––––– Approval –––––––––––––––––––––––––––––––––––––––––––––
Engineer ––––––––––––––––––––––––––––––––––––––––––––– Contractor’s P.O. No. ––––––––––––––––––––––––––––––––––
Approval ––––––––––––––––––––––––––––––––––––––––––––– Representative ––––––––––––––––––––––––––––––––––––––––
Series LF174A
Series LF174A
LEAD FREE
*
Watts product specifications in U.S. customary units and metric are approximate and are provided for reference only. For precise measurements,
please contact Watts Technical Service. Watts reserves the right to change or modify product design, construction, specifications, or materials with-
out prior notice and without incurring any obligation to make such changes and modifications on Watts products previously or subsequently sold.
*The wetted surface of this product contacted by consumable water
contains less than 0.25% of lead by weight.
WARNING !
NOTICE