Navien NCB-190/060H, Installation & Operation Manual

Page: 129 / 145

129 Appendixes
b. Connect a manometer to the offset pressure
port. For dual port manometers, use the
positive pressure side.
Model Altitude Kit Part No. Gas
Type
Offset
NCB-
190/080H
NCB-
190/060H
0 -
5,399 ft
-
NG -0.01 in ±
0.01 in
5,400 -
10,100 ft
NAC-
NH190/080
0 -
10,100 ft
NAC-
L190/080
LP -0.04 in ±
0.01 in
NCB-
240/130H
NCB-
240/110H
0 -
5,399 ft
-
NG -0.06 in ±
0.01 in
5,400 -
10,100 ft
NAC-
NH240/130
0 -
10,100 ft
NAC-
L240/130
LP -0.06 in ±
0.01 in
NCB-
250/150H
0 -
5,399 ft
-
NG -0.06 in ±
0.01 in
5,400 -
10,100 ft
NAC-
NH250/150
0 -
10,100 ft
NAC-
L250/150
LP -0.06 in ±
0.01 in
Table 3. Offset value for low fire
c. Activate multiple zones and set the boiler
to operate at 1-stage MIN mode (refer
to “11.6.7 Setting the Special Operation
Modes“ on page 120). 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
in
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. Set Screw Location
Note
The set screw is located behind
the screw-on cover. This must be
removed first.
d. Activate multiple zones and set the boiler
to operate at 2-stage D. MAX mode (refer
to “11.6.7 Setting the Special Operation
Modes“ on page 120). 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.
Digital
pressure
manometer
Figure 9. Connect Digital Pressure Monometer