28
Fig. 6.2
Fig. 6.3
Max. CO
adjustment
2
Outlet
pressure
test point
Inlet
pressure
test point
Min. CO
adjustment
(under cap)
2
Alpha InTec 40GS2 - Commissioning
Flue Gas Heat Recovery Unit (GasSaver)
The GasSaver is a boiler flue gas heat recovery device. The heat is recovered by using a gas to water heat
exchanger to extract heat from the hot flue gases that are usually exhausted into the atmosphere and the heat
within them wasted. This reclaimed heat is then used to pre-heat part of the mains cold water supply to the boiler,
thereby reducing the energy required (using less gas) to heat the water to the set hot water outlet temperature.
During the process of extracting the heat from the flue gases further condensing of the moisture within the flue gas occurs,
this condensate is used to form a thermal store within the GasSaver, allowing more recovered heat to be stored and used for
recycling thereby using less gas.
The flue gases leaving the GasSaver are drier and at a much lower temperature than normal boiler flue gases thereby
reducing pluming and the problems associated with pluming.
Thermostatic Mixing Valve
A thermostatic mixing valve (factory set at 30°C) is used to mix the output from the GasSaver and the incoming mains cold
water, optimising the performance and extending the pre-heat duration which results in better hot water efficiency and higher
flow rates.
Frost Thermostat
The boiler incorporates a built in frost thermostat which automatically turns on the boiler and pump 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.
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.
Pump Cycle
If the electrical supply is on and the boiler has not operated for 24 hours in heating or hot water, the pump will operate
automatically for thirty seconds every 24 hours.
6.6 CHECK THE BURNER PRESSURES AND COMBUSTION - Figs. 6.2 and 6.3
Press and hold in the reset button for eight seconds and the boiler will fire at a fixed output depending on
the position of the boiler central heating thermostat knob.
Turn the boiler central heating thermostat to maximum to check the maximum central heating burner pressure.
With the boiler central heating thermostat set to maximum fully open a hot tap to check the maximum domestic hot
water burner pressure. In this mode the inlet gas supply pressure and CO/CO
2
ratio can be checked.
Refer to Technical Data, Section 3.1 for the required differential burner pressure values.
Note:
The burner pressure settings have been factory set and should not require adjusting.
Combustion testing must be carried out by a competent person using a calibrated analyser conforming to BS EN 50379 part 3.
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 and check the system volume and pressure.
(Refer to Technical Data, Sections 3.1).
2. Turn off the boiler.
3. Thoroughly flush out the water pipework (refer to Section 4.9). Clean the mains water inlet filter (see Fig. 5.3).
4. Re-pressurise the system as described in Section 6.1.
P1
+
P2
-
+
-
