65
All other parameters are set to for SETPOINT 2 are user selectable based on need.
Note: If the boiler is set up as a sequencing slave and is being commanded to be off by the master,
the Standby Water function will override that and allow the slave boiler to run to maintain the
Standby Water setpoint.
It is possible for the user to connect and configure either two temperature sensors or two pressure
sensors to a PPC4000 and try to use one as the PCV and the other as Standby. However, this would
probably not work well even if one-way valves were used. However, if the PCV sensor (Sensor 1) is
a temperature sensor, the Standby Water sensor (Sensor 2) could be a pressure sensor. This would
restrict the user to a standby water temperature always over the boiling point of water. If the user
wishes to do that, the following Standby Water Temperature/Pressure Table can be used to calculate
the standby water temperature.
Standby Water Temperature/Pressure Table
TRACK MODULATION
Track modulation is the application of a 4-20 mA signal to the sensor 1 input and having the modu-
lation rate move the servos associated with the current profile to the corresponding firing rate posi-
tion. The 4-20 mA input signal corresponds to 0% to 100% firing rate with 4 mA being 0% firing
rate and 20 mA being 100% firing rate.
To use TRACK MODULATION, SENSOR 1 usage must be set to TRACK. There is no setpoint
information associated with TRACK MODULATION as the firing rate is determined by the signal
input level being applied. Typically the 4-20 mA signal is supplied from an external controller hav-
ing its own pressure or temperature input and PID control.
When in TRACK MODULATION mode the PCV signal level is displayed as a 0 to 100% level cor-
responding to the level of the signal being applied. The modulation rate will be identical to this value
and the servos will be moved to their respective positions corresponding to this modulation rate.
After burner turn on and safety start-up, in AUTO the servos will move to the position corresponding
to the TRACK MODULATION input level.
Lockout and shutdown will occur if the TRACK MODULATION input exceeds 21mA or goes
below 3mA.
NOTE: Track modulation bypasses the ability for the PPC4000 to control the burner using its inter-
nal setpoint control. It is recommended that the user configure a digital input for BURNER ON/OFF.
OPERATING SEQUENCE
This PPC4000 control performs burner start-up and shut-down in conjunction with an external
burner flame safeguard controller, YB110 for example. The flame safeguard controller provides
burner management functions such as flame detection, interlock safety, combustion air flow moni-
toring as well as controlling the combustion air fan, ignition, pilot valve(s) and main fuel valve(s).
The start-up and shutdown sequence is handled by a progression of stages, each requiring a certain
set of conditions to move on to the next stage. The progression through the stages requires specific
'handshaking' between the PPC4000 and flame safeguard controllers. This is accomplished with a
variety of signals as shown in the following table.
Pressure
PSI Guage
Saturation
Temp °F
Saturation
Temp °C
Pressure
PSI Guage
Saturation
Temp °F
Saturation
Temp °C
1
215.92
101.82
110
344.16
173.42
10
239.35
115.19
120
350.05
176.69
20
258.74
125.96
130
355.60
179.78
30
273.99
134.44
140
360.87
182.70
40
286.70
141.50
150
365.87
185.48
50
297.65
147.58
160
370.63
188.13
60
307.31
152.95
170
375.19
190.66
70
315.99
157.77
180
379.56
193.09
80
323.89
162.16
190
383.76
195.42
90
331.15
166.19
200
387.80
197.66
100
337.88
169.93