System Checkout; Central Heating - CleaverBrooks CFC-500 Operation, Service And Parts Manual

Central Heating

Start-up sequence central heating request (system in standby):
1. Heat request detected (On Setpoint - On Hysteresis).
2. The CH pump is switched on.
3. After a system Safe Start Check, the Blower (fan) is
switched on after a dynamic ILK switch test (if enabled).
4. After the ILK switch is closed and the purge rate proving
fan RPM is achieved (or High Fire Switch is closed) -
prepurge time is started.
5. When the purge time is complete, the purge fan RPM is
changed to the Lightoff Rate or if used, the damper
motor is driven to the Low Fire Position.
6. As soon as the fan-rpm is equal to the light-off rpm (or
the Low Fire Switch closes), the Trial for Ignition or Pre-
Ignition Time is started (depending on configuration).
7. Pre-Ignition Time will energize the ignitor and check for
flame.
8. Trial for Ignition. Fig. 23–25 on page 59 shows three igni-
tion options. Specifics for timings and device actions are
defined by the OEM or installer.
9. The ignition and the gas valve are switched on.
10. The ignition is turned off at the end of the direct burner
ignition period, or for a system that does use a pilot, at
the end (or optionally at the middle) of the Pilot Flame
Establishing Period (PFEP). For an interrupted pilot sys-
tem this is followed by a Main Flame Establishing Period
(MFEP) where the pilot ignites the main burner. For an
intermittent pilot there is no MFEP.
11. The fan is kept at the lightoff rate during the stabilization
timer, if any.
12. Before the release to modulation, the fan is switched to
minimum RPM for the CH Forced Rate and Slow Start
Enable, if the water is colder than the threshold.
13. At the end of the CH-heat request the burner is switched
off and the fan stays on until post purge is complete.
14. A new CH-request is blocked for the forced off time set
by the Anti Short Cycle (if enabled).
15. The pump stays on during the pump overrun time (if
enabled).
16. At the end of the pump overrun time the pump will be
switched off.
Domestic Hot Water
Start-up sequence DHW-request (system in standby):
1. Heat request detected (either DHW Sensor Only, DHW
Sensor and Remote Command or DHW Switch and Inlet
Sensor, whichever applies).
2. The pump is switched on (after the DHW Pump Start
Delay).
3. After a system Safe Start Check, the Blower (fan) is
switched on after a dynamic ILK switch test (if enabled).
4. After the ILK switch is closed and the purge rate proving
fan RPM is achieved (or High Fire Switch is closed) -
prepurge time is started.
5. When the purge time is complete, the purge fan RPM is
changed to the Lightoff Rate or if used, the damper
motor is driven to the Low Fire Position.
6. As soon as the fan-rpm is equal to the light-off rpm (or
the Low Fire Switch closes), the Trial for Ignition or Pre-
Ignition Time is started (depending on configuration).
7. Pre-Ignition Time will energize the ignitor and check for
flame.
8. Trial for Ignition. Fig. 23–25 on page 59 shows three igni-
tion options. Specifics for timings and device actions are
defined by the OEM or installer.
9. The ignition and the gas valve are switched on.
10. The ignition is turned off at the end of the direct burner
ignition period, or for a system that does use a pilot, at
the end (or optionally at the middle) of the Pilot Flame
Establishing Period (PFEP). For an interrupted pilot sys-
tem this is followed by a Main Flame Establishing Period
(MFEP) where the pilot ignites the main burner. For an
intermittent pilot there is no MFEP.
11. The fan is kept at the lightoff rate during the stabilization
timer, if any.
12. Before the release to modulation, the fan is switched to
minimum RPM for the DHW Forced Rate and Slow Start
Enable, if the water is colder than the threshold.
13. At the end of the DHW-heat request the burner is
switched off and the fan stays on until post purge is com-
plete.
14. A new DHW-request is blocked for the forced off time set
by the Anti Short Cycle (if enabled).
15. The pump stays on during the pump overrun time (if
enabled).
16. At the end of the pump overrun time the pump will be
switched off.

SYSTEM CHECKOUT

This section provides general checkout and troubleshooting
procedures for the Primary Safety function of Falcon devices.
WARNING
Explosion Hazard.
Can cause serious injury or death.
Do not allow fuel to accumulate in the combustion
chamber for longer than a few seconds without igniting,
to prevent danger of forming explosive mixture. Close
manual fuel shutoff valve(s) if flame is not burning at
end of specified time.
WARNING
Electric Shock Hazard.
Can cause serious injury or death.
Use extreme care while testing system. Line voltage is
present on most terminal connections when power is
on.
Open master switch before removing or installing the Falcon
device or Display Module connector.
Make sure all manual fuel shutoff valves are closed before
starting initial lightoff check and Pilot Turndown tests.
Do not put the system in service until you have satisfactorily
completed all applicable tests in this section and any others
recommended by the original equipment manufacturer.
Limit trial for pilot to 10 seconds. Limit the attempt to light main
burner to 2 seconds after the fuel reaches burner nozzle. Do
not exceed manufacturer's nominal lightoff time.
CAUTION
Equipment Malfunction or Damage Hazard.
Each device type is unique. Using existing wiring on a
module change can cause equipment damage. Make
wiring changes when a module is replaced with a
different Falcon device to sequence burner.
65
CB FALCON
750-265