Bosch GWH 715 ES Installation Instructions Manual page 31

A. Once Gas Pressure is adequate
B Press ON/OFF button to turn off the heater.
B Remove brass flat head screw on the exhaust collar
as seen in Fig. 55.
B Insert CO
analyzer probe into the measuring port.
2
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. 55 Measuring port
B While holding the Program (P) button in, press the
ON/OFF button to turn ON the heater (see Fig. 56).
As soon as '188' flashes on the display, release the
Program button. The display should now read P2.
Press ' ' button until "P1" appears on display.
Fig. 56
B. Measuring CO (combustion cover must be
2
installed):
B 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.
B Press '
' until P1 reappears on display.
B Record the CO
reading in P1 below. (Analyzer
2
reading may take several minutes to stabilize).
B Press the '
' button until P2 appears. Unit will
ramp down to low fire and the flow should decrease.
B Record the CO
reading in P1 and P2 below.
2
P2 CO Reading:
2
P1 CO Reading:
2
6 720 608 158
% CO
2
% CO
2
Note: When making
combustion cover is installed.
max. input P1
min. input P2
max. input P1
min. input P2
* 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 values. Changes in these inputs can result in
2
different CO and CO values on the same appliance.
2
Table 16 CO & CO target numbers
2
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 level is off:
2
B Loosen yellow painted philips screw (1) and cover
should rotate down (2) revealing a recessed brass
slotted screw. Fig. 57.
B Turning the slotted screw counter clockwise will
raise P1 CO levels and clockwise will lower P1
2
CO levels. Adjustments to the slotted screw will
2
also change P2 CO
2
B After bringing the P1 CO
press the ' ' button to enter the P2 mode. Verify
CO readings in P2 mode.
2
2. If P2 CO level is off:
2
B Remove yellow painted #40 Torx cover from the front
of the gas valve. (Fig. 58) A plastic #40 Torx screw
will be revealed.
B Turning the plastic #40 Torx screw counter
clockwise will lower P2 CO
will raise P2 CO levels.
2
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
ranges specified in table 16. Repeat steps 1 and 2 as
necesssary until CO values are within the specified
2
ranges.
4. Once CO values are within the specified ranges,
2
verify the CO readings on P1 and P2 do not exceed
values shown in table 16. If values exceed this limit,
inspect vent system and fin coils (chapter 6.1, page 29)
for blockage.
Maintenance and service
adjustments, make
Max. CO
CO range (%)
2
level
Nat. Gas
7.0 % - 7.6 % < 190 ppm
2.3 % - 2.6 % < 55 ppm
LP Gas
8.3 % - 8.9 % < 190 ppm
2.5 % - 2.8 % < 55 ppm
levels.
readings in proper range,
2
levels and clockwise
2
readings are within the
2
sure
31