Kartell K-Rad Type 21 Double Panel Single Convector Radiator 400mm x 500mm

Name: Kartell K-Rad Type 21 Double Panel Single Convector Radiator 400mm x 500mm
Brand: Kartell
SKU: P405K
Price: 37.24 GBP
Availability: InStock

by Kartell

SKU P405K

£37.24 - £37.24

£37.24

£37.24 - £37.24

£37.24

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The Kartell K-Rad Kompact P405K is a Type 21 double panel, single convector radiator, 400 × 500 mm, giving 516 W (1759 BTU/h) at ΔT50. Two water-carrying panels with a single bank of convector fins sit in a 70 mm case: 516 W against 337 W for a Type 11 the same size, for 14 mm more depth. Nett weight is 9.85 kg and it holds 2.05 litres of system water.

Type 21 double panel400 × 500 × 70 mm516 W at ΔT50EN 442 testedWhite enamel RAL 901610-year guarantee

1759 BTU/h

Output at ΔT50 — 516 W

9.85 kg

Nett weight — holds 2.05 l

EN 442

Tested and certified

10 years

Manufacturer guarantee

Applications & suitability

Where it goes

Wall-hung on a sealed or open-vented wet heating system, fixed no lower than 100 mm off the finished floor. At 400 mm high it suits a wall where vertical space is tight.

Typical job

A room needing roughly 516 W on a 70 °C mean water temperature, or 661 W where the system runs at 80 °C. Straight swap for a tired 400 × 500 panel of the same size.

Works with / replaces

Pipe centres are 345 mm with a wall-to-centre of 65 mm or 80 mm, so it lines up with most existing 400 mm-high panels. Case depth is 70 mm against 56 mm for a Type 11 and 105 mm for a Type 22.

When not to choose this

The 516 W figure is at ΔT50. Run a heat pump at low flow temperatures and it falls hard — Kartell’s own correction factor at ΔT30 is 0.515, so you would get about 266 W from this radiator. Size at the ΔT you will actually run, and step up to a Type 22 or 33 if the load needs it.

Key specifications

Brand	Kartell
Model	K-Rad Kompact P405K
Radiator type	Type 21 — double panel, single convector
Heat output
Output at ΔT50	516 W (1759 BTU/h)
Output at ΔT60	661 W (2254 BTU/h)
Size and weight
Dimensions (H × W × D)	400 × 500 × 70 mm
Centre distance	345 mm
Wall to centre	65 or 80 mm
Weight	9.85 kg
Water content	2.05 l
Build and rating
Max working pressure	10 bar
Max working temperature	120 °C
Finish	White enamel, RAL 9016
Standard	EN 442
Warranty	10 years

Installation & compatibility

Fix no lower than 100 mm from the finished floor. Allow 35 mm from the wall to pipe centre for a manual valve, or 45 mm for a TRV. Kartell requires the system to be cleansed and dosed with inhibitor to BS 7593:2019 — skipping it invalidates the guarantee, which covers product replacement only. Leave the protective packaging on until the radiator is fixed and the tappings are cut.