Navien NPE-180A, Руководство по установке

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Installing a Cascading System 41
Measure and adjust the gas/air ratio. 11.
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
Water
Heater
Fuel
High fire Low fire
%CO
2
%CO
2
NPE-180A
NPE-180S
NG 8.9 9.5
LP 10.2 10.8
NPE-210A
NPE-210S
NG 8.9 9.5
LP 10.2 10.8
NPE-240A
NPE-240S
NG 8.9 9.5
LP 10.2 10.8
Table 2. CO
2
and CO value
(CO
2
values must be within 0.5% of the values listed.)
c. Fully open several hot water fixtures and set the water
heater to operate at 1-stage MIN mode (refer to page 43).
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” or 4mm Allen wrench, turn the
set screw no more than 1/4 turn clockwise to raise or
counterclockwise to lower the CO
2
value.
Figure 8. Set Screw Location
Note
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 water
heater to operate at 2-stage MAX mode (refer to page 43).
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.