Baxi Checked against MI

Baxi Assure Combi (25, 30, 36, 25 LPG, 30 LPG, 36 LPG)

Combi, natural gas and LPG

Combustion figures

Figure	Natural gas (G20)	LPG (G31)
CO₂ at high rate More infoHide info Printed as a plus and minus tolerance, e.g. 9.0 + 0.3 – 0.2 means 0.3 above and 0.2 below. From the gas valve setting table (MI 9.3.12 Tab.23 and Setting the gas valve), checked in calibration mode. MI 7.4.2 says the case front panel must be fitted when checking combustion. The commissioning check in MI 7.4.2 gives only CO and CO/CO₂ ratio limits.	9.0% + 0.3 – 0.2	10.5% + 0.5 – 0.1
CO₂ at low rate More infoHide info NG figure is printed 8.5 + 0.1 – 0.4 in Tab.23 and 8.5 + 0.1 — 0.4 (longer dash) in the Setting the gas valve steps; taken as the same figure.	8.5% + 0.1 – 0.4	10.0% + 0.1 – 0.5
Maximum CO More infoHide info From the combustion procedure flowchart (MI 7.4.2 Fig.46), with the case front panel fitted. The MI says NG and LPG data are the same unless stated otherwise.	Max rate < 350ppm Min rate < 350ppm	Max rate < 350ppm Min rate < 350ppm
CO/CO₂ ratio	Max rate < 0.004 Min rate < 0.004	Max rate < 0.004 Min rate < 0.004
O₂	Not given in MI	Not given in MI
Working inlet pressure More infoHide info NG: at the meter 19–23 mbar (MI 7.4.1 Fig.42). Checked at maximum rate; the MI also says the inlet test point pressure must be at least 18 mbar. LPG: supply pressure from the gas category table (MI 14.3). Measurement point not stated in MI. The MI gives no LPG version of the NG pressure diagram.	Appliance inlet 18–22 mbar Gas valve test point 17–21 mbar	37 mbar
Gas rate at maximum More infoHide info Measured with any other appliances and pilot lights turned off (MI 7.4.1).	25 2.71 m³/h 30 3.26 m³/h 36 3.81 m³/h	25 1.98 kg/h 30 2.38 kg/h 36 2.83 kg/h
Flue integrity More infoHide info At the air inlet test point, boiler at maximum rate.	O₂ ≥ 20.6% CO₂ < 0.2%	O₂ ≥ 20.6% CO₂ < 0.2%

From 7750729-01

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
Assure Combi 25	47-077-42	NG
Assure Combi 30	47-077-43	NG
Assure Combi 36	47-077-44	NG
Assure Combi 25 LPG	47-077-45	LPG
Assure Combi 30 LPG	47-077-46	LPG
Assure Combi 36 LPG	47-077-47	LPG

Source: Baxi Assure Combi 25 - 30 - 36, 25 LPG - 30 LPG - 36 LPG installation and service manual, 7750729-01.

Sections: 3.1.3 Gas category; 3.2.1 Technical information; 7.4.1 Check the operational (working gas inlet pressure and gas rate); 7.4.2 Checking combustion - chimney sweep mode; 9.1 General; 9.3.12 Gas valve; 14.3 Differences for LPG models.

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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.