Ideal Checked against MI

Ideal Logic Max Combi C (24, 30, 35)

Combi, natural gas

Combustion figures

Figure	Natural gas (G20)
CO₂ at high rate More infoHide info Table 1 gives this at Max. DHW.	24, 35 9.5% ± 0.7 30 9.3% ± 0.7
CO₂ at low rate More infoHide info Table 1 gives this at Min. CH.	24, 30 8.8% ± 0.7 35 8.9% ± 0.7
Maximum CO More infoHide info At maximum and minimum rate, from the CO level and combustion ratio flowchart.	Less than 350 ppm
CO/CO₂ ratio More infoHide info At maximum and minimum rate, from the flowchart. Section 3.1 gives the same limit as 0.004: above it, clean the boiler.	Less than 0.0040
O₂	Not given in MI
Working inlet pressure More infoHide info Checked at the inlet gas pressure test point with the boiler at maximum rate (hot tap fully open). Minimum meter outlet: 19 mb, allowing 1 mb loss across the pipework. The MI says the 1:1 gas valve lets the boiler give full output at inlet pressures as low as 14 mb, and that the gas cock can reduce the pressure further when measured at its test point (graph of gas cock pressure drop against heat input in MI 1.8). Table 1 gives the gas supply as 2H - G20 - 20mbar.	Appliance inlet minimum 18 mb
Gas rate at maximum More infoHide info Maximum DHW input (Table 3). Maximum CH input is 2.512 m³/h for all sizes (Table 2). Calculated using a gross CV of 38.7 MJ/m³. Check at the meter at full DHW output with no other appliance in use.	24 2.512 m³/h 30 3.135 m³/h 35 3.657 m³/h
Flue integrity More infoHide info At the air inlet test point, boiler at maximum rate.	O₂ ≥ 20.6% or CO₂ ≤ 0.2%

From UIN 222362 A01 (April 2019)

Enter service mode for high and low rate

High rate

Steps not added yet. Follow the MI.

Low rate

Steps not added yet. Follow the MI.

Ending the test: follow the MI.

Models and GC numbers

Model	GC number	Gas
Logic Max Combi C 24	47-349-56	NG
Logic Max Combi C 30	47-349-57	NG
Logic Max Combi C 35	47-349-58	NG

Source: Logic Max Combi C 24 30 35 Installation & Servicing, UIN 222362 A01 (April 2019).

Sections: 1.8 Gas supply; Table 1 General data; Tables 2 and 3 Performance data; 2.22 Commissioning and testing; 2.23 Initial lighting; 2.24 The display (Menu operations: Service mode minimum rate, maximum DHW rate, maximum CH rate); 2.25 General checks; 3.1 Servicing schedule; Flowchart for CO level and combustion ratio check.

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Check these figures against the MI for the appliance in front of you, matched by GC number and manual date. Combustion work needs a calibrated analyser and a Gas Safe registered engineer.