Ideal Checked against MI

Ideal Logic Max Heat² heat only (H12, H15, H18, H24, H30)

Heat only, natural gas

Matched Logic Max Heat² H18 (GC 41-860-27)

Combustion figures

Figure	Natural gas (G20)
CO₂ at high rate More infoHide info Table 1 (Max. CH). The table columns are headed 12, 15, 18, 24 and 30 kW. The air/gas ratio valve is factory set and must not be adjusted.	H12 9.1% ± 0.7 H15 9.4% ± 0.7 H18, H24 9.3% ± 0.7 H30 9.7% ± 0.7
CO₂ at low rate More infoHide info Table 1 (Min. CH).	H12 8.5% ± 0.7 H15, H30 8.8% ± 0.7 H18 8.7% ± 0.7 H24 8.4% ± 0.7
Maximum CO More infoHide info From the commissioning flowchart, checked at maximum and minimum rate, probe in the flue gas sampling point, readings allowed to stabilise.	Less than 350 ppm
CO/CO₂ ratio More infoHide info From the commissioning flowchart, at maximum and minimum rate. The servicing schedule (MI 3.1) says clean the boiler if the ratio is greater than 0.004 at maximum rate.	Less than 0.0040
O₂	Not given in MI
Working inlet pressure More infoHide info MI 1.9: a minimum permitted operating pressure of 18 mb can be assumed at the appliance inlet; the minimum meter outlet pressure is 19 mb. The 1:1 gas valve lets the boiler give full output at inlet pressures as low as 14 mb. Table 1 gives the gas supply as 2H - G20 - 20 mbar. The gas cock test point reads lower than the true inlet pressure; the drop depends on heat input (graph in MI 1.9). Checked at maximum rate (MI 2.31).	Appliance inlet 18 mbar minimum
Gas rate at maximum More infoHide info Table 2 gas consumption at maximum input, based on a calorific value of 38.7 MJ/m³ gross. Check at the gas meter with no other appliance in use (MI 2.37).	H12 1.246 m³/h H15 1.537 m³/h H18 1.872 m³/h H24 2.512 m³/h H30 3.136 m³/h
Flue integrity More infoHide info At the air sample point, boiler at maximum rate (commissioning flowchart).	O₂ ≥ 20.6% or CO₂ ≤ 0.2%

From UIN 228292 A05 (October 2022)

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 Heat² H12	41-860-25	NG
Logic Max Heat² H15	41-860-26	NG
Logic Max Heat² H18	41-860-27	NG
Logic Max Heat² H24	41-860-28	NG
Logic Max Heat² H30	41-860-29	NG

Source: Ideal Logic Max Heat² H12 H15 H18 H24 H30 Installation & Servicing, UIN 228292 A05 (October 2022).

Sections: Table 1 General Data; Table 2 Performance Data; 1.9 Gas Supply; 2.31 Commissioning and Testing; 2.32 Initial Lighting; 2.36 Maximum and Minimum Rates; 2.37 General Checks; 3.1 Servicing Schedule; Section 6 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.