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H2O BOILER
HC SERIES IOM Manual
burner head. At any time after the main gas valve is opened, if flame is not detected for a
period longer than 4
seconds, the burner controller will be deactivated and the main gas
valve will immediately close.
High Temperature Limit:
Each unit is equipped with a “Honeywell” high temperature
limit switch. If outlet water temperature exceeds the temperature set on this switch, switch
will open and the burner controller will be deactivated and the gas valve will immediately
close.
Air Pressure Switches:
Every Burner type is equipped with a low air pressure switch is
installed on the air inlet of the blower and measures air pressure entering the burner. If the
combustion air pressure drops by more than 20% below the nominal air pressure (minimum
pressure of 0.4” wc) for any reason such as air inlet obstruction or exhaust obstruction, the
burner controller will be deactivated and the main gas valve will immediately close.
Relief Valve:
A safety relief valve with prescribed nominal pipe size of 3/4" to 1 1/4”
valve inlet/outlet, at 150 psig relief pressure, is installed on the water outlet manifold and
supplied as standard equipment. When the boiler or water heater is used in heating
applications having working pressures in the range 40–160 psig, an appropriate pressure
relief valve should be installed.
Gas Pressure Switch:
One manual reset low gas pressure switch is installed on the gas
train in between the gas pressure regulator and the first safety shut off valve. If the line
pressure drops below 7” wc, the switch will open and the unit will immediately shut down.
One high gas pressure switch is also installed. If the gas manifold pressure increases above
the pressure on the boiler label, the switch will open and the unit will immediately shut
down. High and Low pressure switches can be also installed directly on the available ports
of the safety shut-off gas valve. Refer to figure 6 for a typical gas train configuration.
Flow Switch:
One Flow switch is installed on the outlet manifold. Flow switch has a very
important role. Flow switch is a part of the safety loop, and during normal operation of the
boiler, it will be in close position. When flow rate of the water drops below the minimum
required flow rate, Flow switch will open and stop the burner immediately. When water
flow rate reaches the minimum flow rate for the specific boiler, Flow switch will close up
and burner will automatically restart.
Notes:
Flow switch installation
Additional flow switch is to be installed on the inlet piping of the boiler (by
user).
Flow switch’s paddle length is sized according to the manufacturer’s instruction
for the intended pipe size.
Contact
H2O BOILER
f
or installation instruction of the Flow switch.
D-VAC Sales Inc. Email: [email protected] Tel: (516) 256-3131 www.dvachvac.com
