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6.5 BOILER OPERATION
With the optional Alpha Diverter Kit fitted, the E-Tec R operates with hot water priority. If the heating is on and
there is a hot water demand the valve will divert the primary hot water to the cylinder until the cylinder sensor is
satisfied. The heating will be held off during this period so it is recommended that a high recovery cylinder is used.
The kit comprises of a diverter valve and cylinder sensor. See Section 5.13.
Central Heating Mode
If there is a call for heat, the fan will run and the premix burner will light. The burner output then automatically adjusts to suit the
system demand; as the temperature of the water in the boiler approaches that set by the adjustable temperature thermostat,
the burner output is reduced. When the set temperature is reached, the burner is turned off. The fan continues to run for 30
seconds, after 3 minutes the burner can relight if required. If the primary sensor has not registered the preset temperature but
the room thermostat is satisfied the burner is turned off. The fan continues to run for 30 seconds. In this instance there is no
delay before the burner will relight. If the pump is connected to the boiler pump terminals a 3 minute pump overrun is activated
between requests.
The fan modulates according to the output required.
Frost Thermostat
The boiler incorporates a built in frost thermostat which automatically turns on the boiler if the water in the boiler falls below
4°C, providing the electrical supply is on and the boiler is in standby mode. The boiler will operate until the water temperature
in the boiler reaches 42°C.
The boiler is supplied with frost protection disabled. This can be enabled by changing parameter P6 to 1. See
Section 6.13.
Any other pipework outside of the boiler must be protected from the risk of freezing and insulated. Additional protection from
an external frost thermostat and pipe thermostats should be considered.
6.6 CHECKING THE COMBUSTION - CHIMNEY SWEEP MODE
As part of the Benchmark Checklist procedure the combustion levels of the boiler when the installation is
completed must be measured and recorded.
The air gas ratio of the boiler has been factory-set and should not require adjusting during commissioning. If
adjustment is recommended or required the engineer must be competent to carry out this work. See Fig. 6.3 for
analyser test point.
If the boiler requires adjusting or setting to operate on LPG, further guidance is detailed in Section 6.11.
Chimney Sweep Mode
Without any CH or DHW demand, press and hold the reset button for eight seconds and the boiler will fire at a fixed output.
The parasol and snowman (
) will flash at the same time to indicate this mode, if a Climatic controller is fitted it will
display ERR>07 code on the controller (this is not a fault).
Using the CH control knob you can change output levels:
•
0%
(Min) control knob at minimum setting
•
99%
(Max output) control knob at maximum setting
This mode will remain active for fifteen minutes or can be cancelled by turning the boiler off.
Use the CH control knob to set the output to minimum to check the minimum CO
2
reading, wait for the boiler stabilise, check
the combustion and record the reading.
Use the CH control knob to set the output to maximum to check the maximum heating CO
2
, again allow the burner to
stabalise and record the reading.
If the CO
2
readings are not within the stated tolerance (refer to Section 3.1) then check the installation including the complete
flue assembly and repeat the above process. If necessary adjust the CO
2
as described in Section 6.12.
The CH control knob can be used to increase and decrease the output in incremental steps if required.
When checking at maximum output the boiler will have a higher noise level, this is normal.
6.7 FINAL COMMISSIONING
1. Allow the heating system to heat up, then balance the system to achieve the necessary temperature
difference across the heating flow and return pipes at the boiler. (Refer to Section 3.1).
2. Turn off the boiler.
3. Thoroughly flush out the water pipework (refer to Section 4.9).
4. Refill and re-pressurise the system as described in Section 6.1.
5. Add the correct level of inhibitor to the system as detailed in the instructions supplied with the inhibitor.
Alpha E-Tec 25R - Commissioning
