Ignition Process; Heat Transfer Process; End Of Sequence - Camus Hydronics DynaFlame DFW501 Installation, Operation And Service Manual

9 If limit, water flow and airflow lights are not lit, the
ignition module will receive a 24V signal at terminal
'TH' thru a purple wire. After performing internal self
checks the ignition module will energize the amber trial
for ignition light and the hot surface igniter at S1 thru a
black and brown wire respectively and close the
auxiliary fan connections thru two blue wires which will
switch a 20Wresistor across the modulating signal. This
will occur whether the appliance is in remote or local
mode. The resistor will case the VFD to see a
minimum modulating signal and cause the fan motor to
decelerate to the frequency programmed for soft start.
The ignition control looks for the set proof current from
the igniter (3.2 +/-0.2A).
10 If the proof current is not reached the module will stop
the ignition sequence after the trial for ignition .The
blue main flame light indicating that the main valve is
energized will not come on and the appliance will go
into lockout. If the proof current is reached the ignition
module sends a 24V signal thru a blue wire marked
'valve" to the 24/115V interface relay on the PCB and
to the proof demand terminal 3 on the on board smart
flame control.
11 115V from the 24/115V interface relay will only reach
the ratio control valve if the proof of closure (POC)
switch in the ratio control valve is closed if provided .If
the switch is in an open position the valve stem travel
indicator visible thru a view window in the valve will not
move even though the blue main flame light will
illuminate. This can occur if there is dirt under the valve
seat or if the POC switch is defective.
12 If the POC switch is initially closed, the blue main flame
light will illuminate and the latching relay on the PCB
allows the 115V signal to the control valve to be
uninterrupted when the control valve drives open and
the POC switch contacts open.
13 After the valve open time (5 or 7 seconds) is ended the
ignition module looks for a minimum flame rectification
signal of 2 µA DC from the flame sensor. If the signal is
present the ignition module will allow the control valve
to remain open, if the ignition module does not see a
continuous signal it will shut down the control valve
and will immediately go into lockout mode for CSD1, or
proceed to two more trials before locking out in the
standard version.
14 The ignition module will go into lockout if it does not
see the flame rectification signal due to the flame
sensor being insulated from oxide deposits or from the
sensor rod grounding out due to improper placement or
from a damaged ceramic insulator.
15 The tip of a properly located sensor rod will be ¾" to 1"
away from the burner surface. The µA reading can be
conveniently taken at the front of the ignition module at
the 'Flame Sense Test' terminals.
1.5.1

IGNITION PROCESS

1 The Ignition module supplies voltage to the Air/Gas
Ratio Control Valve through proof of closure switch and
a latching relay located on the PCB.
2 Air/Gas Ratio Control Valve senses the pressure
differential between the Combustion Air Fan outlet and
the vent outlet and supplies gas to the orifice and into
the Fan inlet to pre-mix with air.
3 The Gas/Air mixture is forced into the Burner and out
of the Burner Ports under pressure at soft start input
rate.
3
4 Hot Surface Igniter lights the Gas/Air mixture and the
Flame Sensor serves as a means to prove Main
Burner Flame by rectification.
5 Burner is now firing at soft start input rate.
6 Variable Frequency Drive adjusts fan speed based on
desired water temperature set point or input signal
from remote operator 4-20 mA or 2-10VDC signal
(must be specified at time of placing order).
7 Burner input rate is variable down to approximately
30% of rate or up to 100% of rate as required to satisfy
the set point.
1.5.2

HEAT TRANSFER PROCESS

1 Burner Input continues to increase until water
temperature reaches the Set Point temperature.
2 Burner Input may stabilize at a fixed rate where
demand equals input.
3 Burner Input will decrease rate when water
temperature approaches temperature Set Point.
1.5.3

END OF SEQUENCE

1 Set Point temperature is satisfied.
2 Power to the gas valves is turned off.
3 Combustion Air Fan ramps to a stop over the factory
preprogrammed time period of 60 seconds.
4 Thermostat is now in a standby mode waiting for the
next "Call for Heat".
WARNING
To minimize the possibility of serious personal injury, fire or
damage to your appliance, never violate the following
safety rules.
WARNING
IMPROPER INSTALLATION, ADJUSTMENT,
ALTERATION, SERVICE OR MAINTENANCE can cause
injury or property damage. Refer to this manual. For
additional information, consult a qualified installer, service
agency or gas supplier.
DO NOT
Do not use this appliance if any part of it has been under
water. The possible damage to a flooded appliance can be
extensive and present numerous safety hazards. Any
appliance that has been under water must be replaced
WHAT TO DO IF YOU SMELL GAS
Do not try to light any appliance. • Do not touch any electric
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.
IMPORTANT
Consult and follow local Building and Fire Regulations and
other Safety Codes that apply to this installation. Contact
the local gas utility company to authorize and inspect all
gas and flue connections.
Installation and service must be performed by Camus
qualified factory trained service technicians.