VDI 2035 Calculator

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Work out your system's litres per kW and check whether your tap water meets VDI 2035; we email you the full report with the steps to follow. Indicative information: always check the equipment manufacturer's requirements.

Current edition: VDI 2035 Part 1, March 2021. Since that edition, Part 1 covers both scale and corrosion; the former Part 2 (corrosion, 2009) has been withdrawn.

Your system

Type of system

Total outputkW Total water volumelitres

Volume: buffer, tanks, pipework and emitters. With several heat generators, the guideline divides by the output of the smallest one.

Tap water hardness Tap water conductivityµS/cm

Water topped up in the last year (if known)litres

Has electric backup heatersOr a generator with less than 0.3 l/kW, such as a wall-hung boiler There is aluminium in the circuitHeat exchangers, radiators or boiler bodies in aluminium alloy Plastic pipe without oxygen barrierOlder underfloor heating or pipe without an EVOH or aluminium layer The circuit contains glycol (antifreeze)

Example loaded: 8 kW heat pump with 300 l and tap water at 25 °fH and 450 µS/cm. Change the values for your case.

Result

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Specific volume

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litres per kW

Maximum hardness

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Your tap water

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Full report by email

Target water values, warnings for your system and steps to follow, calculated from your data. A Q-Tech technician reviews it and sends it to you.

More detail in the article VDI 2035: water quality in heat pumps and heating systems. To have your system water reviewed: Q-Tech on WhatsApp · info@q-tech.es

Information tool by Q-TECH HOUSES DIVISION S.L.UNIP., based on the hardness table and guide values of VDI 2035 Part 1 (March 2021) as published in summaries. It does not replace the official text of the guideline, the manufacturer's manual or an assessment by a competent engineer; if the manufacturer asks for stricter values, those apply. It does not apply to glycol circuits or district heating.