750-392
CBEX-DE
5-15
Fuel Oil Metering Valve
5.17 — Fuel Oil Metering Valve
In the event that a leak occurs in the packing of the metering valve, the packing nut should be snugged gradually
to stop the leak.
If replacement of the metering valve packing is necessary, procure kit
(part number 880-370) and install in accordance with the following pro-
cedure.
1.Shut off the oil flow. Be sure no pressure shows on the gauge.
2.Single-point systems: Match-mark the cam hub and drive shaft.
Match-marking will enable replacement of the cam in its original posi-
tion and result in a minimum of cam adjustment when the burner is
refired.
3.Clamp or hold the metering stem in the down position.
4.Disconnect the linkage assembly from the oil valve stem. Single-point
systems: Loosen the setscrews in the cam hub and rotate, or move the cam to a position where it does not
interfere with stem removal.
5. Withdraw the metering vale stem and spring. Do not drop or mishandle. Check for nicks or scratches. Check
that the pin holding the metering portion is not protruding.
6. Back off the packing gland.
7. Single-point systems: Remove the capscrews holding the jackshaft support bracket so that the bracket can be
moved. It may also be necessary to loosen the supporting bracket on the far end of the shaft.
8. Remove the existing packing and guides. Do not re-use the packing and guides.
9. Lightly coat the stem with the lubricant provided with the packing kit. Place the new packing, o-rings, and
guides onto the stem in the sequence shown. The beveled face of the guides and the Teflon rings must face
upward, with the exception of the upper brass guide which is faced down. Be sure that the o-rings are prop-
erly located.
10. Using the stem as a guide, insert the assembled packing into the cavity, then withdraw the stem.
11. In the event the packing is too high, remove one Teflon packing from each side of the middle brass guide as
needed.
12. Under no circumstances eliminate the two Teflon packings on only one side of the brass guide.
13. Replace the gasket, put the support in place, and secure all fastenings.
14. Replace the metering stem and spring. Lightly lubricate the stem to facilitate insertion and easy movement.
Use care when inserting so that the orifice and the stem are not damaged.
Do not over-tighten the metering valve packing nut. Excessive tightening of the packing nut prevents free movement
of the metering stem. Failure to follow these instructions could result in equipment damage.
!
Caution
FIGURE 5-9. Fuel Stem Packing Kit
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