Appendixes 57
10.2 Cleaning the Heat Exchanger
WARNING
Before cleaning the heat exchanger, make sure the boiler is
off.
To properly maintain the boiler, you should clean the heat
exchanger annually.
To clean the heat exchanger:
1. Press the Power button on the front panel to turn off the
boiler.
2. Disconnect the power supply to the boiler.
3. Turn off both gas and water supply to the boiler.
Note
Wait at least 30 minutes for the heat exchanger to
cool down.
4. Remove the two screws (one at the left bottom and one at
the right bottom) of the front cover assembly to gain access
to the internal components.
c. Fully open a hot water fixture and set the boiler to
operate at 1-stage MIN mode (refer to table 2). Measure
the offset value at low fire and compare it to the values
in Table 3. If the offset value is out of range, the gas valve
set screw will need to be adjusted.
If adjustment is necessary, locate the set screw as shown
in Figure 11. Using a
5
/
32
in or 4mm Allen wrench, turn
the set screw no more than
1
/
4
turn clockwise to raise or
counterclockwise to lower the offset value.
Figure 11. Set Screw Location
Note
The set screw is located behind the screw-on
cover. This must be removed first.
d. At high fire, do not check the offset value and never
adjust the gas valve.
DANGER
Improper gas valve settings can cause severe personal
injury, death or substantial property damage.
