Supplement 4987 Page 2
12. Using the controller, increase demand in short increments. Note flame signal strength and fuel flow at each increment up to 100% demand. When the system is at normal operating temperature, make final adjustment to fuel input using the main gas regulator. Fuel flow can be estimated using table 1. Measure fuel pressure at the tap located on the main gas connection. Correct readings for ± system pressure (see step 3). An 8697 metering orifice is recom- mended for determining fuel flow . 13. Set control back to minimum demand and observe that flame should be stable and have acceptable signal strength. Repeat steps 11 and 12 as necessary.
14. When the system reaches operating temperature close the manual shutoff valves and compare the pressure differential outlined in step 5. The burner should operate satisfactorily at both temperature ex- tremes and in accordance to Figure 1. Operating the burner beyond the design range shown in Figure 1 is not recommended. 15. With the burner firing, check operation of the flame supervision and all safety limits one at a time. Check flame supervisory system by closing the manual shutoff valve, located downstream of the second SSOV. Check operation of the safety limits by manually actuating each switch. The SSOV must de-energize on each limit failure.
ALTERNATE PIPING CONFIGURATIONS for SINGLE BURNER INSTALLATION For multiple-burner installations or single-burner installations not shown, consult North American.
CONTROL: MODULATING WITH SEPARATE LOW-FIRE/BYPASS COMPONENTS
Burner Air Pressure Tap
Combustion Chamber Pressure Tap
Q
R
B
Air to Oven
Blower and Tap
A
Fan
Air from Oven
A – 4987 Zephyr™ B – Flame Protection Tube C – Limiting Orifice D – General-Purpose Solenoid Valve E – Relief Valve (if required) F – Adjustable Port Valve & Actuator G – 8697 Metering Orifice
Vent to a safe location
L
E
K
M
P
H
H – Manual Shutoff J – Leak Test Valve
F
H G
Low-Fire Bypass
J
J
K – Automatic Safety Shutoff Valve #2 L – Vent Valve (for IRI) M – Automatic Safety Shutoff Valve #1 P – Main Gas Pressure Regulator Q – Burner Air Flow ( P) Pressure Switch (Purge) R – Combustion Air Switch
D C
CONTROL: OFF - LOW - HIGH
Burner Air Pressure Tap
Combustion Chamber Pressure Tap
Q
R
B
Air to Oven
Blower and Tap
Fan
A
Air from Oven
A – 4987 Zephyr™ B – Flame Protection Tube C – Limiting Orifice D – General-Purpose Solenoid Valve
Vent to a safe location
C
L
E
E – Relief Valve (if required) G – 8697 Metering Orifice H – Manual Shutoff J – Leak Test
C
K
M
P
D
H
H G
K – Automatic Safety Shutoff Valve #2 L – Vent Valve (for IRI) M – Automatic Safety Shutoff Valve #1 P – Main Gas Pressure Regulator Q – Burner Air Flow ( P) Pressure Switch (Purge) R – Combustion Air Switch
J
J
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