- To make it easier to remove a threaded pilot tip from the
burner in the future. Use anti-seize compound on threaded
discharges and screw hand tight into the burner mounting.
Installing a pipe union or a 4041 between the pilot mixer and
the pilot tip will also speed up pilot tip removal.
- Adding at least 5 pipe diameters of pipe between the mixer and
the pilot tip adds additional mixing length to insure good quality
- The preferred location for pilot tips (and UV cells) is on the top
or side of a burner so that scale, dirt, and refractory crumbs
cannot fall into it.
- "Zero governor" pilot systems require an atmospheric regulator
(like the 7350-##-A) to supply gas at zero gauge pressure to the
pilot mixer, but zero governor systems only work well in open air
applications when there is no chance of back pressure.
If the burner back pressure varies (like in many pilot systems),
the 7350 ratio regulator vent should be cross-connected with an
impulse line to the 4031 mixture pressure tap or to the 4031 air
pressure tap. Using the mixture pressure tap provides better air/
fuel ratio control (especially on suction systems).
- If the pilot regulator inlet gas pressure exceeds its pressure
rating, install a pressure-reducing regulator upstream. 7344
Regulators reduce up to 25 psi gas to 4-12"w.c. For capacities or
inlet pressures beyond the range of 7344 Regulators, see Bulletin
7337 and 7349. Use a separate pilot regulator. Do not run pilot
gas through any of the regulators for main burner gas because
those regulators cannot turn down low enough for pilot gas fl ow,
and will therefore chatter or shut-off .
- The inlet pressure to the pilot gas ratio regulator (7350) should
be at least 2 osi greater than the connected pilot air or mixture
- Avoid stressing and distorting valves and regulators, small pilot
regulators may be easily damaged by incorrect use of wrenches.
Put your wrench on the end nearest the pipe that it’s being
- Undersized piping and plugged lines are common causes of
pilot problems. Avoid corrugated connectors and hoses, they
cause more pressure loss than regular pipe and fi ttings. Tubing
has ½ the area, and 4 times the pressure loss of the same “size”
pipe. It’s OK to use tubing that has as much fl ow area as pipe.
"OD × .045"wall tubing in place of
- Avoid thread dope or Tefl on tape applied over the ends of pipe
thread, it can break loose and plug pilot tips.
- Always blow out each fi tting and section of pipe before and
aft er installing it, (but dont put pressure on regulators and
- A fi lter on the combustion air blower inlet will help prevent
plugging the small openings in the pilot system with dirt and
- Short run impulse lines for pilot systems should be
" thin wall
tubing. 304 stainless tube
" OD x .035" wall is a good choice.
Copper tubing can also be used, but is more susceptible to
Pilot Installation Tips | 4011/4021 Pilot