Navien NFC-175, Руководство по установке и эксплуатации

Страница: 108 / 124

108 Appendixes
Option 2. Using Digital Manometer
a. Open the offset pressure port by loosening the screw two
turns as shown in Figure 8.
Digital pressure
manometer
Figure 8. Connect Digital Pressure Monometer
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
NFC-175
NFC-200
0-5,399 ft NAC-N200
NG
-0.04 in
±0.01 in
5,400-10,100 ft NAC-NCH200
0-10,100 ft NAC-LC200 LP
-0.02 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.
Note
For operation mode selection, refer to “11.4.7
Setting the Special Operation Modes” on page
100.
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 7. 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.
Figure 7. 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 “11.4.7 Setting the Special
Operation Modes” on page 100). 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.