Fisher 1098-EGR - Startup; Dual-Pilot Boiler Fuel Control

Types 1098-EGR and 1098H-EGR
9
Startup
1. Slowly open the pilot supply line hand valve.
2. Slowly open the upstream block valve and
partially open the downstream block valve for
minimum ow. Slowly open the hand valve in the
control line.
3. Adjust the pilot setting, if necessary.
4. Completely open the downstream block valve.
5. Slowly close the bypass valve, if any.
Dual-Pilot Boiler Fuel Control
Applications
Boiler Fuel Pressure Control
To enhance proper operation and adequate response
to negative pressure shock condition in low differential
pressure boiler fuel control applications, use the
Type 1098-EGR boiler fuel conguration:
• Type 1098-EGR with Type 6352 pilot
• Size 70 Actuator
• Quick Opening Cage
• Yellow Main Spring
• Type Y600AM or 627M Auxiliary Pilot mounted in
parallel with the Type 6352 pilot
To provide faster response, two pilots mounted
in parallel sense downstream pressure. To provide
faster response, two pilots mounted in parallel sense
the downstream pressure. The Type 6352 pilot is
the primary controlling pilot and the Type Y600AM
or 627M auxiliary pilot stands by until it senses a
negative pressure shock condition. The auxiliary
pilot opens, allowing additional ow into the actuator,
increasing the stroking speed and providing faster
response. See Figure 5 for schematic. The quick
opening cage allows maximum capacity at shorter
travels to decrease stroking time in opening and
closing directions. The service conditions should not
exceed 20 psig (1,4 bar) maximum inlet pressure and
10 psid (0,69 bar d) maximum differential pressure.
Figure 4. Typical Dual-Pilot Boiler Fuel Installation
48A6566-A
B1622
TYPE 1098-EGR REGULATOR WITH
STANDARD TYPE 6352 WORKING PILOT
CONTROL
LINE
1/2-INCH
(13 mm)
PIPE
TO PILOT
LIGHT
PILOT
SUPPLY LINE
1/2-INCH
(13 mm)
PIPE
VENT
FILTER
TYPE Y600AM
AUXILIARY PILOT
VENT
4 MAIN PIPE DIAMETERS
10 MAIN PIPE DIAMETERS