andrews CWH120/200, Installation, Operation And Maintenance Manual

Page: 35 / 44

MAXXflo Water Heater
35 35 INSTRUCTIONS FOR COMMISSIONING • SECTION 5
CONTROL AND ADJUSTMENT AT FULL LOAD
1. Switch the water heater off and flush system until the
tank is completely cooled down
2. Put the water heater in operation
3. Press the reset button down for longer than 5 seconds; L
appears in the display. Pressing the
reset button again, C 00 appears in the display.
Press the + button to select the burner module to be run
at full load
Burner module 1
Burner module 2
Burner module 3
Burner module 4
All burner modules simultaneously
Burner module 2 not present
Press the reset button to choose the desired burner
module. The burner can now function at full load or low load
using the + and – buttons respectively. The actual burner
capacity appears in the display alternately with:
Burner module 1 full load
Burner module 1 low load
Select full load with the + button, when the actual burner
capacity is above 90%, the CO2 percentage can be
measured and set.
4. Measure the CO2 percentage and compare it with table
1 (page 33). The CO2 percentage can be adjusted using
the “Full Load” Setscrew (A) on the gas regulation unit
(see Fig 15). The CO2 percentage can be increased by
turning the setscrew to the left.
5. Now check the CO2 percentage at low load.
CONTROL AND ADJUSTMENT AT LOW LOAD
1. Select low load with the – button. When the actual
burner capacity is above 25%, the CO2 percentage can
be measured and set.
2. Measure the CO2 percentage and check it against table
1 (page 33). The CO2 percentage can be adjusted using
the “Low Load” Setscrew (b) (2mm Alan Key) on the gas
regulation unit (see Fig 15).
The CO2 percentage can be increased by turning the
setscrew to the right.
3. Check the CO2 percentage at full load again. If there
is another adjustment at full load, check it at low load
again.
4. Press the reset button. A new burner module can now
be selected using the + and – buttons. The heater is
brought into operation again by repeatedly pressing on
the – button until C 00 appears in the display. Press
the reset button again and the display switches back to
normal.
If the appliance is left in commissioning mode
by mistake, after 10 minutes the controls will
automatically revert back to normal operation.
DECOMMISSIONING
Turn the electricity supply off. Then, turn off the gas tap
in the supply pipe. The water heater must be empty when
there is a risk of freezing. Please note: if the electricity
supply remains switched off for a long period, the self test
of the control no longer works. This happens once every
24 hours and activates pumps momentarily to prevent the
pumps from sticking, amongst other things.
Fig 15 – Setscrews