750-211 (revised 2009)
Promethean Boilers, Model 4WI Manual
5-11
5.8 — Induced Flue Gas Recirculation (IFGR) Setup
Once the main flame is established, turn the burner switch to the “off ”
position and observe that the flame is extinguished promptly. The
flame may continue to burn for a second or two after normal shutdown
due to the gas remaining downstream from the fuel valve. If the flame
continues to burn for a longer period or during blower motor spin-
down, it could indicate a main gas valve leak. Immediately turn the
burner switch “off ” and close the main gas cock. Investigate and cor-
rect the cause of the valve leakage before relighting the burner.
FIGURE 5-12. Gas Train and Shutoff Cock
The main gas valve should provide a tight seal, if nothing prevents tight closure. Foreign material may be present in
either the new or renovated gas lines unless adequate care is taken in cleaning and purging.
When the conditions covered in Section 5.7 and in Sections 5.1, 5.2, and 5.3 are assured, the burner is ready for fir-
ing. Refer to Section 5.8 for further starting and operating information.
5.8 — Induced Flue Gas Recirculation (IFGR) Setup
It is recommended that the final “installed” settings be recorded for future reference. The settings should be
marked on the linkage as well.
Normally, once the system has been set and adjusted, the settings should not be changed unless conditions (includ-
ing boiler settings) change. In that case, it will be necessary to contact your local Cleaver-Brooks authorized repre-
sentative for assistance.
After the IFGR system is initially set up, it will start up with the boiler as an integrated boiler system. After shut-
down periods in which maintenance and/or adjustments have been performed on the fuel cams, fuel and air link-
ages, or IFGR control linkages, the recommended approach to startup is:
1. Set all boiler components to their initial settings as discussed in the appropriate chapters of this manual.
2. Check fan impeller and motor rotation. Correct rotation is counterclockwise when viewed from the front of the
boiler.
3. Verify that all the IFGR components are set to the settings recorded on the Start Up report (as noted by the
Cleaver-Brooks authorized representative during original setup). Be sure that all linkages are secure.
NOTE: The burner and control system are designed to provide a pre-purge period of fan operation prior to establish-
ing ignition spark and pilot flame. Do not attempt to alter the system or to take any action that might circumvent the
feature.
NOTE: Initial IFGR linkage settings and adjustments must be established by a Cleaver-Brooks authorized representa-
tive. Setup of the low emission (LE) option requires simultaneous consideration of air-to-fuel ratios and NO
x
levels.
This can only be accomplished with proper combustion emissions monitoring equipment with NO
x
, O
2
, CO, and
smoke spot measuring capability.
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