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Adjusting Gas/Air Flow - Bosch Greentherm 9800 SE 160/199 Manual

Indoor residential and comme rcial tankless water heaters
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Adjusting Gas/Air flow

The CO2 can only be adjusted by a certified gas technician
with a calibrated CO2 analyzer.
▶ Before adjusting Gas/Air flow, turn off
any backup appliance (example; solar)
to avoid high inlet water temperature.
Appliance is pre-adjusted by default with
factory parameters, gas/air adjustment is
required in Natural Gas installations where
energy content is less than 900 BTU/cu ft,
and in installations with repeated
unresolved errors (ref. to chapter 9).
Adjustment may be required when
converting to LP. In these situations, a CO
analyzer can be used to assure a more
accurate air adjustment.
▶ One factor that may affect CO
improper gas pressure. Please see
Chapter 4.13 for the procedure to
measure gas pressure and record your
The P1 minimum operating gas pressure is 3.5" WC for Natural
Gas and 8" WC for Propane. Do not proceed in adjusting CO
until pressure is at or above these levels, but not to exceed
10.5" WC for Natural Gas and 13" WC for Propane.
Only possible after access Authentication
menu ( section 6.6).
Always start the adjustments by U1 (L1) and
P1 (A1) followed by U2 (L2) and P2 (A2).
Greentherm 9800 SE 160/199 | SEC 199
8.9.1 Access to CO
▶ Open a hot water tap and let the appliance work for 2 or 5
▶ Remove the screw from the flue adaptor on the left side of
the appliance, as seen in fig. 48.
▶ Insert CO
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.
levels is
Fig. 48
8.9.2 Adjusting the maximum flow (Parameter P1)
▶ Access to menu P1.
▶ 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 goes back to P2, open more hot water fixtures to
allow sufficient flow and access to P1 menu.
▶ Touch symbols
measuring port
Allow the appliance to stabilize before
performing CO2 and CO readings.
Let appliance warm up and wait for 2 or 5
minutes for each CO2 and CO readings.
This will avoid wrong CO2 and CO read-
analyzer probe into the measuring port. The tip
measuring port
It's recommended to use CO
perform appliance adjustment in case of gas
conversion or abnormal combustion noise.
to select U1 - L1 Auto Adjust.
Troubleshooting | 51
analyzer to
6 720 816 815 (2016/10)



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