Franke Zip Hydroboil

Eighteen listings, and the first thing to settle is what a Hydroboil is. Not a tap in a worktop: a boiling water unit that hangs on the wall with its own two-way tap on the front, plumbed and wired in place, replacing kettles and urns. Capacities run 2.5, 5, 7.5, 10, 15, 25 and 50 litres, each in brushed stainless steel or white epoxy powder coated steel, with the Hydroboil Plus at 3 and 7.5 litres.

Size it by cups, not by litres

Franke rates each model by the maximum cups it can deliver at any one time, a cup being 167ml. That is 12 to 15 cups from the 2.5 litre, 25 to 30 from the 5, 36 to 45 from the 7.5, 50 to 60 from the 10, 75 to 90 from the 15, 120 to 150 from the 25 and 250 to 300 from the 50. The 25 and 50 litre units carry two taps.

Recovery matters as much as the draw off. Franke gives approximate recovery of a cup a minute on the 2.5, 5 and 7.5 litre models, 1.5 cups on the 10, 2 on the 15, 3 on the 25 and 6 on the 50. A site where thirty people all want tea at once wants headroom in the tank, not just a quick recovery rate.

The 50 litre needs a three phase supply

Settle this before you order. The 2.5, 5 and 7.5 litre models draw 1.5kW, the 10 and 15 litre 2.4kW and the 25 litre 3.0kW, all on a single phase 220/230V supply. The 50 litre is rated at 7.2kW on a three phase 380/230V supply, so it suits only premises that already have three phase. Have an electrician confirm the supply and circuit before committing to the largest unit.

Hydroboil, Hydroboil Plus, and how it differs from a HydroTap

Both hold water at the boil in a stainless chamber with mains water kept separate in a second chamber, and both use the cool touch two-way tap: forward for precise cup filling, pressed back it locks on for continuous flow into a pot. The standard Hydroboil works within 3°C of boiling. The Plus holds within 1°C of a set point factory set to 98°C and adds energy features, cutting to micro pulse power when idle and sleeping after two or four hours of no use. For chilled or sparkling water as well, and a slim tap on the sink rather than a unit on the wall, see the Zip HydroTap or boiling water taps. Filters and fittings are on Franke plumbing parts, and the full range is under Franke.

Frequently Asked Questions

What size Zip Hydroboil do I need?

Work in cups rather than litres. Franke rates a cup at 167ml and gives 12 to 15 cups at one time from the 2.5 litre, 25 to 30 from the 5, 36 to 45 from the 7.5, 50 to 60 from the 10, 75 to 90 from the 15, 120 to 150 from the 25 and 250 to 300 from the 50. Match the figure to your worst simultaneous demand, not your average.

How quickly does a Zip Hydroboil reheat after a big draw off?

Franke gives an approximate recovery rate per minute for each model. The 2.5, 5 and 7.5 litre units recover about a cup a minute, the 10 litre 1.5 cups, the 15 litre 2 cups, the 25 litre 3 cups and the 50 litre 6 cups. That is why a busy staff kitchen is better served by a larger tank than by hoping a small one catches up between users.

Does a Zip Hydroboil need a special electrical supply?

Most of the range does not. The 2.5, 5 and 7.5 litre models are rated at 1.5kW, the 10 and 15 litre at 2.4kW and the 25 litre at 3.0kW, all on a single phase 220/230V supply. The 50 litre is different: it draws 7.2kW on a three phase 380/230V supply. Have an electrician confirm the supply and circuit before ordering the 50 litre.

What is the difference between a Hydroboil and a Hydroboil Plus?

Temperature control and energy use. The standard Hydroboil is designed to work within 3°C of boiling point. The Plus holds within 1°C of a set point factory set to 98°C, and adds energy features: micro pulse standby power, a sleep mode after two or four hours of no use, a sleep when dark setting, a programmable daily on and off clock, and a steam heat boost that preheats incoming water.

Does a Zip Hydroboil need a water filter?

Filtration is optional rather than built in, and Zip lists Hydroboils among the applications for its universal in-line filter kit. Zip recommends changing the cartridge on a regular six month maintenance programme. A tundish is also worth considering: fitted to the vent it creates an air gap between the unit and the overflow waste, and gives you a visible check if the unit ever overflows.