18. Measure and adjust the gas/air ratio.
Option 1. Using Combustion Analyzer (recommended)
a. Loosen the screw, rotate the plate and remove the gasket to access
the emissions monitoring port as shown in Figure 7.
b. Insert the analyzer into the port (Figure 7).
Figure 7. Insert the Analyzer
Table 2. CO
2
value
(CO
2
values must be within 0.5% of the values listed.)
c. Fully open several hot water fixtures and set the boiler to
operate at 1-stage MIN mode (refer to page 8).
Measure the CO
2
value at low fire. If the CO
2
value is not
within 0.5% of the value listed in Table 2, the gas valve set
screw will need to be adjusted. If adjustment is necessary,
locate the set screw as shown in Figure 8. Using a 5/32 in
or 4 mm Allen wrench, turn the set screw no more than
1/4 turn clockwise to raise or counterclockwise to lower
the CO
2
value.
Model
Fuel
High fire
Low fire
%CO
2
%CO
2
NCB-180
NG
8.9
9.5
LP
10.2
10.8
NCB-210
NG
8.9
9.5
LP
10.2
10.8
NCB-240
NG
8.9
9.5
LP
10.2
10.8
b.
Connect a manometer to the offset pressure port. For dual
port manometers, use the positive pressure side.
Model
Kit Part No.
Gas Type
Offset
NCB-180
NAC-01
LP
-0.03"±0.01"
NAC-100
NG
-0.04"±0.01"
NCB-210
NAC-02
LP
-0.02"±0.01"
NAC-200
NG
-0.04"±0.01"
NCB-240
NAC-03
LP
-0.02"±0.01"
NAC-300
NG
-0.04"±0.01"
Table 3. Offset value for low fire
c.
Fully open a hot water fixture and set the boiler to
operate at 1-stage MIN mode (refer to table 2). Measure
the offset value at low fire and compare it to the values in
Table 3. If the offset value is out of range, the gas valve set
screw will need to be adjusted.
If adjustment is necessary, locate the set screw as shown
in Figure 10. Using a 5/32”or 4mm Allen wrench, turn the
set screw no more than 1/4 turn clockwise to raise or
counterclockwise to lower the offset value.
Figure 10
The set screw is located behind the screw-on cover.
This must be removed first.
d.
At high fire, do not check the offset value and never adjust the gas
valve.
DANGER
Improper gas valve settings can cause severe personal injury, death or
substantial property damage.
Figure 8. Set Screw Location
The set screw is located behind the screw-on cover.
This must be removed first.
d. Fully open several hot water fixtures and set the boiler to operate at
2-stage D. MAX mode (refer to page 8). Measure the CO
2
value at
high fire.
If the CO
2
values do not match Table 2 at high fire, do not adjust the
gas valve. Check for the proper Gas Orifice.
DANGER
Improper gas valve settings can cause severe personal injury, death or substantial
property damage.
Option 2. Using Digital Manometer
a.
Open the offset pressure port by loosening the screw two
turns as shown in Figure 9.
Figure 9. Connect Digital Pressure Monometer
12.
Once the CO
2
or offset values have been confirmed, apply the
included conversion stickers to show that the appliance has
been converted to propane gas. Place these labels adjacent to
the rating plate as shown in Figure 11.
Figure 11. Proper Placement of Gas Conversion Labels
Manifold Gas Pressure ratings can change due to
updated orifice sizes. Please confirm new
manifold pressures approved by CSA before
production of gas conversion labels.
Setting the Operation Mode
1.
Using the Front Panel, press and hold the Diagnostics Button or over 5
seconds until “1.PAR” is displayed.
2.
Press the + (Up) button two to change the display to“3.OPR”.
3.
Press the Information Button once to access the Operation Mode menu.
4.
Press the + (Up) button once to set the boiler to operate at 1-stage MIN
(“MIN.1”).
5.
To set the boiler to operate at DHW 2-stage MAX, press the + (Up)
button 4 times or until "D.MX.2" is displayed.
6.
To exit the Operation Mode and return the boiler to normal operation,
press the Reset button twice.
Diagnostics
Mode
Reset
Navien America, Inc.
20 Goodyear lrvine, CA 92618
TEL +949-420-0420 FAX +949-420-0430
www.navienamerica.com
Digital pressure
manometer
