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Ideal Heating Logic Max Combi C30 30kW vs Vaillant ecoFIT pure 835 35kW combi

The Vaillant ecoFIT pure 835 35kW combi has 5kW more hot water output and runs 1.7 litres a minute more hot water.

Last reviewed 13 September 2026

Key differences

Specifications side by side

Ideal Heating Logic Max Combi C30 30kWVaillant ecoFIT pure 835 35kW combi
Hot water output30.3 kW35 kW
Central heating output25.6 kW26.7 kW
ErP classAA
Seasonal efficiency94%94%
Dimensions700 x 395 x 278 mm700 x 390 x 295 mm
Weight28.6 kg33 kg
Warranty10 years10 years when installed by Vaillant Advance installer
Hot water flow rate12.4 litres per minute14.1 litres per minute

Sources: Ideal Heating Logic Max Combi C30 30kW, Vaillant ecoFIT pure 835 35kW combi. Figures vary by model year and options, so check with the supplier before you commit.

Buy or hire the Logic Max Combi C30 30kW if...

A gas combi boiler with 30.3 kW of hot water output, sized for a three-bed house with one or two bathrooms. It delivers about 12.4 litres per minute of hot water, which decides how well a shower runs while a tap is on. Warranty: 10 years. Seasonal efficiency is 94%.

Full Logic Max Combi C30 30kW specifications →

Buy or hire the ecoFIT pure 835 35kW combi if...

  • you want one that has 5kW more hot water output
  • you want one that runs 1.7 litres a minute more hot water
  • you want one that puts out 1kW more to the radiators

A gas combi boiler with 35 kW of hot water output, sized for a larger house with two bathrooms. It delivers about 14.1 litres per minute of hot water, which decides how well a shower runs while a tap is on. Warranty: 10 years when installed by Vaillant Advance installer. Seasonal efficiency is 94%.

Full ecoFIT pure 835 35kW combi specifications →

Common questions

What is the difference between the Ideal Heating Logic Max Combi C30 30kW and the Vaillant ecoFIT pure 835 35kW combi?

The Vaillant ecoFIT pure 835 35kW combi has 5kW more hot water output and runs 1.7 litres a minute more hot water. The Ideal Heating Logic Max Combi C30 30kW is a gas combi boiler, 30.3 kW hot water output; the Vaillant ecoFIT pure 835 35kW combi is a gas combi boiler, 35 kW hot water output.

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