Pilot Installation Tips | 4011/4021 Pilot
Cross-connecting a 7350-02-A pilot regulator to the mixture pressure of the 4031 mixer will provide the best ratio control for a ¾ " pilot systems. The gas pressure upstream of the pilot regulator should be set at least 2 osi (3.5"w.c.) higher than the mixture pressure. A common mixture pressure to use is 3-5"w.c. So set the gas pressure upstream of the 7350 to 5-6 osi (9- 11"w.c.).
1849-04 Petcock is an 1829A-04 valve with 1929-04 hose nipple
Mixture pressure tap (1849-04 Petcock shown open) After set-up is done, pressure tap valves that can release fuel into the room should be removed or plugged.
Air inlet (take-off well upstream of main air control valve)
1120-0 Pilot butterfly air valve
Spring adjusting under cap
Gas inlet (take-off from pilot gas safety train)
An atmospheric pilot regulator helps maintain proper air/fuel ratio if the pilot flow conditions change. (install close to the mixer)
Cross-connecting a 7350-02-A pilot regulator to the air pressure of the 4031 mixer will provide acceptable ratio control in cases where the fuel cannot be used in the impulse line. A common air pressure to use is 6-8 osi (10.5-14"w.c.), so set the gas pressure to 10-12 osi (17-21"w.c.). For CSI compliant systems set air to 6 osi (10.4"w.c.) and gas pressure of the 7350 to 8 osi (0.5 psi), (13.8"w.c.).
Air pressure tap (1849-04 Petcock shown open valves must be closed without meter attached)
Pilot mixture gas adjusting screw (limiting orifice)
Mixture pressure tap (shown open) Check mixture pressure here or take premix sample with a 8666 Testip. After set-up is done pressure tap valves that can release fuel into the room must be removed or plugged.
Bulletin 4011/4021 Page 8
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