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Stiebel Eltron Mini 4-2 Single Handwashing Sink Electric Tankless Water Heater

SKU 222039
Original price $159.00 - Original price $159.00
Original price
$159.00 - $159.00
Current price $159.00
in stock

The Stiebel Eltron Mini 4-2 tankless water heater is designed for installation at the point-of-use, or under the sink. 240V/208V - 3.5kW Mechanical

The Mini heats water instantaneously as it flows through the unit. Stand-by heat losses are completely eliminated. The efficient heating elements are controlled by a simple flow switch. Additionally, all Mini water heaters are equipped with a safety high limit with a manual reset.

Flow controls and faucet aerators are highly recommended in conjunction with tankless water heaters. The Mini™ 3.5-1 and 4-2 models ship with a 0.66 GPM pressure compensating flow reducer/aerator. All aerators are designed to fit the most common faucets. No pressure relief valve, drains, or circulating pumps are needed.


  • Extremely compact design saves space. Only 7.5″ x 6.5″.
  • Major energy savings
  • Unlimited supply of hot water
  • Proven reliability
  • Can be mounted with fittings pointing up or down
  • Perfect for Bathroom sinks (Commercial, Residential)
  • Ideal energy/water-saving solution for Boats, RVs, small cabins where space is a premium and hot water is required
  • Sleek design is appealing and can be mounted in plain sight
  • Can be mounted with fittings pointing up or down
  • Pre-wired pigtail included

Order Processing and Shipping

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Mechanical modelsMini™ 2-1 (231045)Mini™ 2.5-1(232098)Mini™ 3-1 (220816)Mini™ 3.5-1 (232099)Mini™ 4-2 (222039)Mini™ 6-2 (220817)
Thermostatic ModelsMini™-E 2-1 (236011) Mini™-E 2.5-1 (236135)Mini™-E 3-1 (236010)Mini™-E 3.5-1 (236136)Mini™-E 4-2 (236009)Mini™-E 6-2 (236008)
Phase - 50/60 Hz1
Voltage120 V120 V120 V120 V240 V or 208 V240 V or 208 V
Wattage1.8 kW2.4 kW3.0 kW3.5 kW3.5 kW2.6 kW5.7 kW4.3 kW
Amperage15 A20 A25 A29 A15 A13 A24 A21 A
Min. recommended circuit breaker size (1)15 A (SP)20 A (SP)25 A (SP)30 A (SP)15 A (DP)25 A (DP)
Min. recommended wire size (2)14/2 AWG12/2 AWG10/2 AWG 10/2 AWG14/2 AWG10/2 AWG
Minimum water flow to activate unit 
Mechanical Units0.21 gpm (0.8 l/min0.40 gpm (1.5 l/min)0.40 gpm (1.5 l/min)0.40 gpm (1.5 l/min)0.40 gpm (1.5 l/min)0.77 gpm (2.9 l/min)
Thermostatic Units0.21 gpm (0.8 l/min)0.30 gpm (1.15 l/min)0.30 gpm (1.15 l/min)0.30 gpm (1.15 l/min)0.30 gpm (1.15 l/min)0.48 gpm (1.8 l/min)
Water temp. range Electronic units are adjustable from 86–122°F (30–50 °C)
Energy Factor (EF) (Mechanical / Thermostatic)0.98 / 0.97 (UEF) 1.0 / 0.990.99 / 0.99 0.99 / 0.99 0.99 / 1.00.99 / 1.0
Weight3.44 lb (1.56 kg)
DimensionsWidth 7½" (19.0 cm) x Height 6½" (16.5 cm) x Depth 3¼" (8.2 cm)
Water volume in unit0.026 gal (0.1 l) 
Minimum pressure30 psi (2 bar)
Working pressure150 psi (10 bar)
Tested to pressure300 psi (20 bar)
Water connections (4)3 /8˝ O.D. flexible braided stainless steel hose connectors

Mini™ 2-1 is internally restricted to 0.32 gpm (1.2 l/min). Mini™-E 2-1 is internally restricted to 0.40 gpm (1.5 l/min).

 All Mini™ models ship with appropriately sized pressure compensating flow-reducer/aerators that must be installed. 

1 Nominal mains voltage is 110–120 V and 220–240 V. 

2 This is our recommendation for overcurrent protection sized at 100% of load. Check local codes for compliance if necessary. Tankless water heaters are considered a non-continuous load. 

3 Copper must be used. Conductors should be sized to maintain a voltage drop of less than 3% under load. 

4 Mechanical units suitable for supply with cold water only. Thermostatic units can accept inlet water of 122 °F.

Mini/MiniE Brochure and Sizing Guide

Specifications and Installation Guide

Use and care/Warranty Information

Crossover Guide




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