CAC / BDP BW4BAH-91, Installation, Operation & Maintenance Manual

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MAIN AIR VENT: for down fl ow systems or diaphragm 
type expansion tanks (not provided)

Before system is 

fi

 lled with water, there is air in pipes and 

radiation units. Some air will be trapped as system is 

fi

 lled. 

It is possible to eliminate most of this air through air vents 
on radiation units. Main air vent will speed and simplify this 
process. Install main air vent on highest point in supply 
main when all radiation is below top of boiler.

AUTOMATIC FILL VALVE (not provided)

For safe, ef

fi

 cient operation, hot water system must be 

fi

 lled with water. Adding new water, when needed can 

be done manually (by use of hand valve in water supply 
line). This requires regular attention to system’s needs. 
Automatic 

fi

 ll valve or pressure reducing valve accomplishes 

this without attention. Install in supply line on hot water 
boilers only. Valve operates through water pressure 
differentials. It does not require electrical connection.

BURNER SOLENOID VALVE (provided)

Beckett and Carlin oil burner’s use standard solenoid valve. 
Upon burner shut down, standard solenoid valve stops 

fl

 ow of oil to nozzle. Without solenoid valve, oil pump 

continues to pump oil to burner nozzle until burner motor 
winds down below pumps cutoff speed. Riello oil burner 
has delay solenoid valve. Delay solenoid valve provides 
same shut down action as standard solenoid valve, plus 
on burner start up delay solenoid valve remains closed for 
additional 15 seconds. Allows burner fan motor to pre-
purge combustion chamber and oil pump to bring supply 
oil pressure up to its set point helping to provide clean light 
off.

LIMIT CONTROL (provided) Refer to manufacturer 
instructions provided with limit control

Water temperature limit control in limit is adjustable and 
may be set: as low as 140°F so long as return water 
temperatures to boiler are no less than 120°F, or as high as 
220°F so long as boiler and heating system have adequate 
circulation to remove heat from boiler otherwise steam may 
be created in boiler. Refer back to “System Piping” section 
for more information.

DRAIN VALVE (provided)

Drain valve is manually operated valve provides means of 
draining all water from boiler and heating system. It should be 
installed in reducing tee where return line enters boiler. 

CIRCULATOR (provided) 

Every forced hot water system requires circulator. Separate 

circulator or zone valve is required for each zone, if there 

are two or more zones. Circulator must have capacity to 

provide circulation required by heating system. Circulator 

should be connected to supply main and must be wired 

into boiler’s electrical system. See “System Piping” section 

for piping con

fi

 gurations with circulator located on supply 

main piping using zone circulators or zone valves. When 

piping is arranged with zone circulators and no bypass 

piping, circulator provided with boiler may be used as 

zone circulator. Both piping arrangements allow circulator 

to pump away from expansion tank and show how piping 

should be arranged to allow heating system to be easily 

purged of air

.

EQUIPMENT AND OPTIONAL ACCESSORIES

Taco 007 Pump Curve