Slant/Fin J-390 IV. Check Combustion and Fuel Input Rate, Gas valve adjustment

Jaguar Model J-390			37
IV. CHECK COMBUSTION AND FUEL INPUT RATE		2. If the CO2 is not 0.2% at the low firing rate, then the
A. Start and run the burner at the high firing rate, by using the			gas valve needs to be accessed for proper adjust-
			ment. Remove the boiler jacket top cover, 3 front
“System Test” mode in the “View and changing system
			cover panels, and enclosure front cover (see figure 2
setting” menu. Refer to Table 5 on page 33.
			on page 3 for locations.
1.	Measure the CO, and CO2 of the flue gas. A	3. Remove the cap that covers the gas valve offset
	flue sample port is provided in the vent pipe (See		screw (see figure 25 for location). Adjust the low fire
	Figure 2 on page 3). The CO should not exceed 100
			CO2 to be 0.2% lower than the recorded high fire
	ppm, when the combustion is correct. The CO2 is not
			CO2. Turn the offset clockwise to increase the CO2
	field adjustable, and should be in the range of 8.5% to
			value. Turn the offset counter-clockwise to decrease
	9.5% (9.0% is the nominal reading). Record the actu-
			the CO2 value. Replace the offset cap when adjust-
	al high firing rate CO2, as it will be used as a refer-
			ment is complete.
	ence in setting the low firing rate CO2 (in Step B).
		4.	Once the correct combustion is confirmed at the
2.	Once the correct combustion is confirmed at the
			low firing rate, check the fuel input rate of the gas
	high firing rate, check the fuel input rate on the
			meter. BTUH Input = cu. ft. metered in 3 minutes x
	gas meter.
			heating valve of the gas * x 20.
	BTUH INPUT = cu. ft. metered in 3 minutes x	5. If the fuel input is not at the rate specified on page 2
	heating value of the gas* x 20		at the low firing rate, then the blower speed
*	The higher heating value of the gas can vary for		should be adjusted to attain the specified input rate.
			This can be done by using the “Change blower RPM
	different localities. Consult the gas supplier for this
			for low input” mode in the “View and changing
	value in BTU/cu.ft.
			System Setting” menu. Refer to Table 5 on page 33.
3.	If the fuel input is not at the rate specified on page 2
			Increasing the blower rpm will increase the fuel input
	at the high firing rate, then the blower speed should		rate, and decreasing the blower rpm will decrease the
	be adjusted to attain the specified input rate. This can		fuel input rate.
	be done by using the “Change blower RPM for high	6.	Replace the boiler enclosure front cover, 3 jacket front
	input” mode in the “View and changing System
			cover panels, and top cover (see figure 2 on page 3
	Setting” menu. Refer to Table 5 on page 33. Increas-
			for locations).
	ing the blower rpm will increase the fuel input rate,
	and decreasing the blower rpm will decrease the fuel	C Exit the “System Test” mode, once the combustion and fuel
	input rate.	input rate has been checked and adjusted, if necessary.

B. In the “System Test” mode in the “View and Changing	Refer to Table 5 on page 33.
System Setting” menu, use the “down” push button to
switch to the low firing rate. Refer to Table 5 on page 33.

1.Measure the CO and CO2 of the flue gas. The CO should not exceed 30 ppm, when the combustion

is correct. The CO2 should be 0.2% lower than the high firing rate CO2 (recorded in Step A). If this reading is obtained, then proceed to Step 4.

COMBUSTION

BLOWER

OUTLET

PRESSURE TAP

OFFSET ADJUSTMENT

SCREW (BELOW CAP)

VENTURI

GAS VALVE

INLET

PRESSURE TAP

GAS PIPE

Figure 25. Gas valve adjustment.