Operating instructions

C. Diaphragm-Type Expansion Tank (Not Provided)
The diaphragm-type expansion tank takes the place of a conventional expansion tank. Read instructions packed with tank assembly carefully.
The tank comes with a 10-12 psi air charge. This is the same as the pressure produced in system by automatic fill valve. When system is first filled,
tank contains little or no water.
As water is heated, its pressure increases. It expands into tank compressing the air in tank. This compressed air cushion permits water in system
to expand as temperature changes.
The diaphragm-type expansion tank can be mounted on the air purger fitting or at any other convenient place in the supply or return line. It is
recommended to locate the diaphragm type expansion tank (a) in the supply line with the circulator located after the expansion tank or (b) off the
3/4-in. tapping provided on the top of the rear casting with the circulator mounted directly off the boiler’s supply piping connection. This
configuration allows the circulator to “pump away” from the expansion tank for improved air elimination and system performance. The air
eliminator fitting or air purger is not provided. The air eliminator fitting or air purger is used to help remove air from the system before it reaches
the radiators. It should be installed in the supply line. Air left in the system can cause noises in the pipes and inefficient circulation in the radiators.
D. Air Eliminating Fitting (Air Purger) (Not Provided)
An air purger is used to remove air from system. It is installed in supply line. It eliminates air from water before it reaches radiators and bleeds
off this air.
E. Main Air Vent for Downflow Systems or Diaphragm-Type Expansion Tank (Not Provided)
Before a system is filled with water, there is air in pipes and radiation units. Some of it will be trapped as system fills. It is possible to eliminate
most of this air through air vents on radiation units. A main air vent speeds and simplifies this process. It should be installed on highest point in
supply main when all radiation is below top of boiler.
Fig. 13—Wiring Connections to Aquastat Relay
A95602
TO
115V
SUPPLY
L1
NH
115V 60 CYCLE
SUPPLY
24 VOLT
THERMOSTAT
L2 T T
TO
24V
THERM
AQUASTAT
RELAY
Fig. 14—Wiring Diagrams for Boilers With and Without Tankless Heater Coil
A02231
T
T
B2
C1
L1
L2
B1
ZC
ZR
C2
SUPPLY
POWER
120V
L8124C
AQUA STAT
W -WHITE
COLOR CODE
Y -YELLOW
0 -ORANGE
BK-BLACK
W
W
R
B
K
T
B
T
G
L1
L2
B1
B2
C1
R
C2
3
BK
W
CIRCULATOR
BK
W
NEUTRAL
HOT
120/60/1 OVERCURRENT
L8148A
AQUA STAT
24 VOLTS
CLASS II,
LINE VOLTAGE
PROTECTED
DISCONNECT
24 VOLT
t˚
THERMOSTAT
120V
POWER
SUPPLY
W
BK
O
W
BK
OIL BURNER
W
MOTOR
B
K
OIL VALVE
IGN. TRANS
BK
BK
W
BK
BK
Y
F
F
Y
RELAY
CELL
CAD
CIRCULATOR
THERMOSTAT
24 VOLT
t˚
PROTECTED
DISCONNECT
120/60/1 OVERCURRENT
FIELD WIRING
W
R
BK
HOT
NEUTRAL
V
BL
CELL
W
O
F
F
Y
Y
RELAY
BL
V
BK
CAD
OIL VALVE
W
BK
OIL BURNER
MOTOR
BK
BK
IGN. TRANS
BK
BK
BL -BLUE
V -VIOLET
BL -BLUE
V -VIOLET
W -WHITE
Y -YELLOW
0 -ORANGE
BK-BLACK
FIELD WIRING
LINE VOLTAGE
CLASS II,
24 VOLTS
COLOR CODE
BW5B BW4B
—13—
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