Camus Hydronics DynaFlame DFW501 Installation, Operation And Service Manual page 33

The auto re-set limit is set to 210° F and is fixed. In addition
to the auto reset limit the factory installs a manual re-set
limit set to 250° F.
Figure 29: Mode 6 Piping Schematic
Mode 7: External Target Temperature using System
Temperature Sensor
The external input signal can be provided from a BMS,
EMS or a tekmar tN4 System Control. The external input
signal creates an internal demand and changes the boiler
target according to a linear scale. The control modulates
the boiler to maintain the boiler target at the outlet sensor.
An internal heat demand is generated when an analog
positive 2-10VDC signal is applied to the +V input and a
negative DC signal is applied to the Com/- input.
Table 12 shows the relationship between various external
signals to the boiler target temperature. A 4-20mA signal
can be converted to a 2-10VDC signal by installing a 500
resistor on the external input signal device's terminal.
If the system sensor is ½ (half) of the differential below the
Boiler Target, the BTC 1 then changes the proportional
modulation output to the START modulation setting, then
closes the Stage contact (pins 15 & 16) to proceed to trial
for ignition. The burner remains at minimum modulation
until the flame is proved and then the modulating output
changes the boiler burner out to maintain the programmed
boiler target temperature at the system sensor. If the inlet
sensor reaches ½ (half) of the differential above Boiler
Target, the burner shuts off. Once the external heat
demand is removed, the BTC 1 turns off the appliance and
operates the boiler pump based on the PUMP DELAY
setting.
The auto reset limit is set to 210
to the auto reset limit, Camus installs a manual reset limit
o
set to 250 F.
Figure 30: Mode 7 Piping & Electrical Layout
o
F and is fixed. In addition
Mode 8: External Direct Drive Operation
This mode is designed only for hydronic heating operation.
This mode allows for an external control to operate the boiler
through an analog direct drive input signal provided by a
boiler sequencing control, such as, the S12 Sequencer. When
operating in this mode the external heat demand and DHW
demand are disabled.
An external boiler sequencer provides a positive 0-10 VDC
input signal to the control at +V(in), and the negative signal
is applied to the Com/- input.
The boiler remains off while the direct drive input signal
range is between 0 to 0.5VDC. Once the direct drive input
signal reaches 0.5VDC the control turns on the appliance
pump and changes the modulating output to Start
Modulation level until the flame is proved and then the
modulating output is adjusted to track the direct drive input
signal up to the maximum of 10VDC which is equivalent to
maximum input rate. When the direct drive signal
modulates down to 0.5VDC, the boiler operates at minimum
fire. When the signal drops below 0.5VDC the burner is
shut off and the pump continues to circulate until the PUMP
DELAY timer expires, whereupon the pump shuts off.
The external boiler sequencer can specify the boiler inlet
temperature. However, the BOIL MAX setting limits the
highest temperature at the outlet sensor. If the outlet
o
temperature exceeds 210
immediately changes to 0% and the burner is shut off. The
burner is to remain off until the minimum off timer is
satisfied and the boiler outlet temperature falls by 2
o
(1 C) below the BOIL MAX setting.
Figure 31: Mode 8 Piping & Electrical Layout
F, the modulating output
o
F
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