Maintenance and service
RTG 199 HE – 6 720 811 617 (2016/01)
39
▶ Dismantle all parts for inspection and cleaning.
Fig. 70 Condensing heat exchanger
▶ Check the condensing heat exchanger for any obstruction.
▶ Flush the condensing heat exchanger unit with water.
▶ Check all gasket and o-rings for damage and replace if necessary.
▶ Assemble the condensate unit and all other parts in reverse order of
disassembly.
7.5
Adjusting CO2
The CO2 can only be adjusted by a certified gas technician with a
calibrated CO2 analyzer.
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.71.
▶ 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. 71 Measuring port
▶ Press the ON/OFF button to turn ON the heater.
▶ Immediately following, press and hold simultaneously buttons
or
and
for 3 seconds, until display reads P2.
Fig. 72
▶ 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 gpm. (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.
It is important to inspect and properly replace the
gaskets and o-rings using the available kit
(8 704 701 116 0).
CO
2
adjustment is required in Natural Gas
installations where energy content is less than 900
BTU/cuft, and in installations with repeated
unresolved EA and EC errors (ref. to page 44
“Problem solving”).
CAUTION:
▶ One factor that may affect CO
2
levels is improper gas
pressure. Please see Chapter 4.15 for the procedure
to measure gas pressure and record your findings
below:
+
P
