Operating Instructions; Testing For Gas Leaks And Purging The Gas Supply; Boiler Operation; Central Heating Mode - Dunkirk DCBF-100 Manual

FOR YOUR SAFETY READ BEFORE OPERATING
WARNING
!
If you do not follow these instructions
exactly, a fire or explosion may result
causing property damage, personal injury or
loss of life.
• This appliance is equipped with an ignition
device which automatically lights burner. Do
NOT try to light this burner by hand.
• Before operating smell all around appliance
area for gas. Be sure to smell next to floor
because some gas is heavier than air and will
settle to the floor.
• Use only your hand to turn the gas shutoff
valve. Never use tools. If valve will not turn
by hand, do not try to repair it, call a qualified
service technician. Force or attempted repair
may result in fire or explosion.
• Do not use this appliance if any part
has been under water. Immediately call
a qualified service technician to inspect
appliance and to replace any part of control
system and any gas control which has been
under water.
CAUTION
! !
WHAT TO DO IF YOU SMELL GAS
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use
any phone in your building.
• Immediately call your gas supplier from a
neighbor's phone. Follow the gas supplier's
instructions.
• If you cannot reach your gas supplier, call the
fire department.
10.1 Testing For Gas Leaks And Purging The Gas
Supply
• With boiler gas service cock closed (spindle flats at
right angles to valve). Pressure test gas supply and
inlet pipe work connection to boiler gas service cock
for soundness.
• Loosen screw of pressure inlet gas test port on gas
valve. See Figure 9-3 Gas Valve. Verify gas supply is
ON. Open boiler service cock to purge.
• Retighten test port screw and test for gas leaks.
Close boiler gas shutoff device.

10 - OPERATING INSTRUCTIONS

10.2 Boiler Operation

Domestic hot water supply always takes priority over
central heating.
Demand for hot water required during central heating
period, boiler automatically switches to hot water mode
until demand is satisfied i.e. storage water is to required
temperature.
This interruption in central heating is only when demand
for hot water is present and should not be noticed by
the User.

10.3 Central Heating Mode

1.
2.
3.
4.
5.

10.4 Domestic Hot Water Mode

• When a tap is opened and water flow is sensed by
• Water in the boiler is diverted from central heating
• Combustion fan will come on at ignition speed,
• Flame sensor will acknowledge presence of flame in
• After initial stabilization period, the control board
• Domestic call for heat ends when tap is closed and
• There is no anti-cycling mode after a DHW call for
55
With demand for heating, pump circulates water
through the primary circuit.
Combustion fan comes on at ignition speed, closing
the air pressure switch, allowing power to spark
generator and gas valve, creating ignition in the
combustion chamber.
Flame sensor acknowledges presence of flame in
combustion chamber sending a signal to the control
board.
After initial stabilization period the control board
monitors supply and return temperatures and
modulates fan speed and gas rate accordingly.
Once boiler satisfies CH call for heat, the unit will
shutdown and enter 3 minute anti-cycling mode.
The boiler pump will operate for 3 minutes to
dissipate any residual heat.
If there is a subsequent CH call for heat, boiler will
wait 3 minutes to operate.
DHW flow switch, domestic hot water call for heat is
initiated.
system to domestic hot water heat exchanger to heat
incoming domestic water.
closing the air pressure switch, allowing power to
flow to spark generator and gas valve, creating
ignition in the combustion chamber.
combustion chamber and send a signal to the control
board.
monitors supply and return temperatures and
modulates fan speed and gas rate accordingly.
DHW flow switch does not see water flow.
heat if there is demand.
240013375 REV A, [07/01/2021]