High Air Pressure Switch Settings; Limit Controls Check - CleaverBrooks CFC Operation, Service And Parts Manual

6. Manually modulate the burner to high fire. Adjust the gas choke
if necessary to obtain desired O2% (5% - 6%).
7. Modulate to low fire and fine tune offset screw to obtain desired
O2% (5% - 6%).
Verify adjustments by modulating back and forth between low and
high fire.
While setting combustion observe gas pressure at low fire and at
high fire. Ensure pressure is within limits shown in Table 4-3.

8. High Air Pressure Switch settings

The High Air Pressure witch (HAPS) is used to safely shut down the
boiler in case of a blocked flue or blocked condensate condition.
The HAPS switch setting for each model CFC can be found below:
Table 4-4 HAPS Settings
Model
CFC-500
CFC-750
CFC-1000
CFC-1500
CFC-1800
CFC-2500
The HAPS has a manual reset, similar to the High/Low gas pressure
switches.
Note: In the event of a HAPS lockout, investigate possible causes
before attempting to restart boiler.

9. Limit Controls Check

The Modulation Off (operating limit) and High Limit functions can
be tested while the boiler is operating by adjusting the respective
setting downward and allowing the boiler outlet temperature to rise.
The Modulation Off point is the sum of the Modulating setpoint and
the Hysteresis Off value. The Modulation On point is the setpoint
minus the Hysteresis On value.
When the boiler 's outlet temperature exceeds either of these
settings, the boiler will shut down. When the operating limit is
exceeded, the boiler will automatically recycle upon the outlet
temperature dropping below the on point. When the High Limit is
exceeded, a lockout should result requiring a manual reset of the
control after the temperature has dropped below the high limit
setting.
Before testing the High Limit, temporarily set the Modulation OFF
point higher than the High Limit setting.
Restore Modulation OFF and High Limit to operational settings after
testing.
Specific settings are determined by application. Maximum High
Limit for Model CFC is 210 deg F.
Part No. 750-263
Setting
3.5" W.C.
3.5" W.C.
3.5" W.C.
4.5" W.C.
4.5" W.C.
5.25" W.C.
Chapter 4 — CFC Commissioning
4-19