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  • HUUM UKU Extension Box (for heaters over 10.5 kW) — product photo
  • HUUM UKU Extension Box (for heaters over 10.5 kW) — close-up detail

HUUM Extension box

HUUM UKU Extension Box (for heaters over 10.5 kW)

An add-on power box that lets a HUUM UKU control run heaters above its own limit, and it's required for the HIVE 12, 15 and 18 kW. It works alongside UKU Local or UKU Wi-Fi, not instead of them.

Works with HUUM heaters only. See the heater and sizes it fits

One version for 240 V North American installations; it pairs with UKU Local or UKU Wi-Fi.

What’s included

  • UKU Extension Box 63 (240 V, 2 × 63 A)

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Works with

The HUUM heaters and sizes HUUM rates this extension box for.

Overview

About this extension box

A UKU control switches HUUM heaters up to 11 kW on its own. The HIVE 12, 15 and 18 kW draw more current than that, so HUUM requires this Extension Box to carry the extra load. The UKU panel and main module still run the sauna; the Extension Box adds switching capacity, taking a UKU system up to 18 kW, per HUUM.

HUUM's North American wiring sheet describes a 240 V two-pole unit rated 2 × 63 A in an IPX4 enclosure. It mounts on a wall outside the sauna room, close to the UKU main module, and fixes with four screws. HUUM calls for the main module and the Extension Box to be fed from separate circuit breakers, so plan the panel space with your electrician.

It works only with HUUM UKU Local and UKU Wi-Fi controls. In our range it's needed for the HIVE 12, 15 and 18 kW; every other HUUM heater we carry tops out at 10.5 kW and runs without it.

In Ontario, control and heater wiring is a job for a Licensed Electrical Contractor, or for you in your own home after filing an ESA notification (permit).

Questions about this extension box

Does the Extension Box replace the UKU control?

No. You still need UKU Local or UKU Wi-Fi to set the temperature and heating time. The Extension Box only adds power-switching capacity.

Do I need it for a 10.5 kW heater?

No. HUUM rates the UKU main module up to 11 kW, so the Extension Box is only required above that. In our range, that means the HIVE 12, 15 and 18 kW.

Does it need its own breaker?

Yes. HUUM's wiring sheet says the main module and the Extension Box must be on separate circuit breakers. Your electrician sizes them from the heater manual.

Documents

Manuals from HUUM.

Documents are hosted by HUUM and can change without notice; your electrician or installer works from the manual that ships with the product. Need a document in another format? Ask us.

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