Part Number 550-110-641/0605
7
PFG SerieS 7 GaS-Fired Water Boiler — Boiler Manual
Use circulators or zone valves in each circuit for multiple
circuit applications.
Filling the system
1. Close manual air vents, drain cock, and automatic air vent,
if used.
2. Fill to correct system pressure. Correct pressure will vary
with each application. Residential systems are often de-
signed for 12 pounds cold fill pressure.
3. Open automatic air vent one turn, if used.
4. Air must be vented for the system. Air in the system can
interfere with water circulation and cause improper heat
distribution.
a) Open manual water feed valve.
b) Starting on the lowest floor, open the air vents one at
a time until water squirts out. Close vent.
c) Repeat with remaining vents.
d) Close manual water feed valve when correct boiler
pressure is reached.
5. To purge air from system, install isolation valve in return
piping.
a) Connect a garden hose to the purge valve located
above the isolation valve.
b) Close isolation valve. Open purge valve.
c) Open hand water feed valve and allow system to purge
all air. If system has more than one circuit, purge each
circuit separately by opening each balancing valve one
at a time.
d) Close purge valve.
e) Open isolation valve.
f) Fill the system to the correct pressure.
6. Keep the system filled by occasionally opening the air
vents as in Step 4 above. Add water to make up system
pressure.
Figure 2b Piping – Closed type expansion tank
Multiple zoning
1. Zone valves:
a) Refer to zone valve manufacturer’s literature for wiring
and application. A separate transformer is required to
power zone valves.
b) Provide balancing valves to adjust the flow so it is
about the same in each zone.
2. Circulators:
a) Zoning with circulators requires a relay for each cir
-
cuit.
b) Install flow control valves to prevent gravity circula
-
tion.
c) Provide balancing valves to adjust the flow so it is
about the same in each zone.
d) Size common return and supply piping for total flow
of all circulators.
Figure 2c Piping – Closed diaphragm type expansion tank
Use circulators or zone valves in each circuit for multiple
circuit applications.
