18
GAS-FIRED BOILER Boiler Manual
Piping Symbol Legend
circulator
(w/ isolation flanges)
gate valve
globe valve
ball valve
swing-check valve
flow-check valve
spring-loaded check valve
hose bib / boiler drain
thermostatic radiator valve
TRV (straight)
circuit setter
manual 3-way valve
zone valve
air separator
backflow preventer
diaphragm-type
expansion tank
pressure reducing valve
diff. pressure bypass
anti-scald rated
mixing valve
pressure gauge
4-way motorized
mixing valve
3-way motorized
mixing valve
pressure relief valve
float -type
air vent
heat exchanger
union
Munchkin heater
radiant manifold
Super Stor
indirect DHW tank
vacuum breaker
thermostatic radiator valve
TRV (angle)
circulator w/
integral flow check)