Specifications

Maintenance and service | 37
6 720 644 936 (2013/01)830 ES
Static Gas Pressure: “ WC
P1 Operating Pressure: “ WC
The P1 minimum operating gas pressure is 3.5" WC for Natural Gas and
8" WC for Propane. Do not proceed in adjusting CO
2
until pressure is at
or above these levels, but not to exceed 10.5" WC for Natural Gas and
13" WC for Propane.
A. Once Gas Pressure is adequate
▶ Press ON/OFF button to turn OFF the heater.
▶ Remove brass flat head screw on the exhaust collar as seen in Fig.63.
▶Insert CO
2
analyzer probe into the measuring port. The tip of the
probe should be in the center of the flue pipe (approx 1.5" inserted).
Avoid air gaps between probe and measuring port as they can alter
readings.
Fig. 63 Measuring port
▶ Press the ON/OFF button to turn ON the heater.
▶ Press and hold simultaneously buttons or and for 3
seconds, until display reads P2.
Fig. 64
▶ Press button until “P1” appears on display.
B. Measuring CO
2
(Combustion cover Installed):
▶ Open all hot water taps to achieve a flow rate of at least 6 gallons per
minute. (1 tub and 2 sinks should be sufficient). If heater display
reverts back to P2, open more hot water fixtures to allow sufficient
flow. Press + until P1 reappears on the display.
▶ Record the CO
2
reading in P1 below. (Analyzer reading may take
several minutes to stabilize).
▶ Press the ‘+’ button until P2 appears. Unit will ramp down to low fire
and the water flow should decrease.
▶ Record the CO
2
reading in P2 below.
P1 CO
2
Reading: % CO
2
P2 CO
2
Reading: % CO
2
Note: When making adjustments, make sure combustion cover is
installed.
C. Adjusting CO
2
:
Note: P1 adjustment will change the P2 reading. Confirm the P1
value BEFORE adjusting the P2 level.
1. If P1 CO
2
level is off:
▶ Loosen yellow painted Phillips screw (1) and cover should rotate
down (2) revealing a recessed brass slotted screw. Fig.65.
▶ Turning the slotted screw counter clockwise will raise P1 CO
2
levels
and clockwise will lower P1 CO
2
levels. Adjustments to the slotted
screw will also change P2 CO
2
levels.
▶ After bringing the P1 CO2 readings in proper range, press the
button to enter the P2 mode. Verify CO
2
readings in P2 mode.
2. If P2 CO
2
level is off:
▶ Remove yellow painted #40 Torx cover from the front of the gas valve.
(Fig.66) A plastic #40 Torx screw will be revealed.
▶ Turning the plastic #40 Torx screw counter clockwise will lower P2
CO
2
levels and clockwise will raise P2 CO
2
levels.
Note: This screw adjustment is very sensitive and should be made in
small increments. It may take several minutes for readings to stabilize.
3. Verify both P1 and P2 CO
2
readings are within the ranges specified in
table35. Repeat steps 1 and 2 as necessary until CO
2
values are within
the specified ranges.
Final Readings
P1 CO
2
Reading: % CO
2
P2 CO
2
Reading: % CO
2
D. Returning to Service:
1. Return slotted screw cover to original position.
2. Reinstall Torx cover.
3. Remove CO
2
analyzer probe and reinstall flathead screw with gasket
in exhaust collar.
4. Press ON/OFF button to turn OFF the heater and then turn ON the
heater.
5. Heater is ready for normal operation.
CAUTION:
▶ One factor that may affect CO
2
levels is improper gas
pressure. Please see Chapter4.14 for the procedure
to measure gas pressure and record your findings
below:
+
P
CO
2
range (%)
Max. CO level
(measured)
Nat. Gas
max. input P1 6.3 % - 6.9 % < 250 ppm
min. input P2 2.3 % - 2.6 % < 60 ppm
LP Gas
max. input P1 8.3 % - 8.9 % < 250 ppm
min. input P2 2.6 % - 2.9 % < 60 ppm
* Values above are for climate controlled conditions. Inputs such
as gas pressure, heating value of the gas, humidity and
temperature of combustion air all impact CO and CO
2
values.
Changes in these inputs can result in different CO and CO
2
values on the same appliance.
Table 35 CO
2
& CO target numbers
+