HUUM DROP Electric Sauna Heater

Before Installation

Before proceeding with installation, carefully read the following:

• Ensure the main fuse amperage matches the heater parameters.
• Verify the heater output (kW) is suitable for the sauna room volume (ft³ /m³). For uninsulated brick, tile, glass, or log walls, add 53 ft³ (1.5 m³) per square meter of such wall. Refer to Table 2 and Table 3 for suitable output.
• Confirm that minimal safety distances to the ceiling and walls are maintained, as detailed in Table 1.

NB! The manufacturer's warranty is void if the heater output does not match the calculated sauna room volume.

Installation

Positioning of the Heater

The heater must be positioned to ensure a safe distance from flammable materials.

• Consult Table 1 for minimal safety distances to the ceiling and walls.
• Place the heater to avoid dangerous situations and minimize accidental contact.
• Remove the protective film from the steel plate behind the heater before installation.
• The heater with stones weighs approximately 143.3 lb (65 kg). Ensure the wall structure is strong enough to support this weight. Attach the heater frame securely to the wall.
• NB! The DROP 7 and 9 models include a heat diverter and heating element retainer, with separate installation instructions provided.

Electrical Connection

NB! Electrical work must be performed by a certified electrician.

• The power cable must comply with UL 62 (US) and CSA 49 (Canada) requirements.
• Maximum current amperage and required circuit breaker sizes are in Table 2 and Table 3.
• It is recommended to connect the unit without an earth-leakage circuit breaker (RCD).

Table 1: Minimum Safety Distances (in / mm)

Figure 1: Positioning of the heater. This diagram illustrates the heater mounted on a wall, showing dimensions A through E and minimum gap requirements. Dimension A is the distance from the heater to the wall, B and C are horizontal distances, D and E are vertical distances, and MIN gap is the distance to the ceiling.

Installing Inside the Sauna Bench

The HUUM DROP can be partially mounted within a sauna bench or floor.

• At least 14.8 in (375 mm) of the heater should protrude from the bench surface.
• Use the embedding flange accessory to cover the edges of the bench opening.

Figure 2: Installing HUUM DROP electric heater inside the sauna bench. This diagram shows a side view of the heater partially recessed into a bench, indicating the minimum immersion depth of 14.8 inches (375 mm).

Table 2: Electrical Specifications (240 V)

* For uninsulated walls (brick, tile, glass, log), add 53 ft³ (1.5 m³) per square meter of wall.

Table 3: Electrical Specifications (208 V)

* For uninsulated walls (brick, tile, glass, log), add 53 ft³ (1.5 m³) per square meter of wall.

ATTENTION! Use only heat-resistant cables. The junction box must be waterproof and installed at a maximum height of 19.7 in (50 cm) from the floor.

Wiring Steps:

• Open the heater's electrical box cover.
• Route the cable through the rubber bushing.
• Connect the power cable to the terminal block according to the circuit diagram.
• NB! The cable must pass through the heater reflector opening first.
• Close the cover.
• Secure the cable with a cable strap.
• Mount the heater on the wall frame, ensuring it is stable.

Circuit Diagrams: Shows wiring connections for 240V and 208V systems for DROP 4/6 and DROP 7/9 models, indicating L1 and L2 terminals.

Laying the Heater Stones

The HUUM DROP requires approximately 121.3 lbs (55 kg) of stones with a diameter of 2-4 in (5-10 cm).

• Round stones are recommended for design and water flow.
• Natural stones like olivine diabase are suitable.
• Avoid decorative stones as they may not accumulate heat well, crack, and can block air holes or damage heating elements.

ATTENTION! Warranty does not cover defects caused by using unsuitable stones.

Wash stones clean of dust before laying.

Requirements for Laying Stones:

• Wear gloves for protection.
• Place stones one by one; do not pour or throw them.
• Start with larger stones at the bottom and sides, using smaller stones to fill gaps and secure larger ones.
• Lay stones tightly but allow for air circulation.
• Place stones between heating elements to support them and prevent contact. Do not push stones too hard.
• Ensure heating elements are not visible through the stones. Ladling water directly onto elements shortens their lifespan.

NB! If heating elements are not properly surrounded by stones, safety distances are invalid due to increased heat radiation. Ensure elements are not visible!

Check stones annually for broken pieces and replace as needed.

Diagrams of Stone Filling: Illustrates four scenarios: 1. [Incorrect] Too tightly filled, 2. [Incorrect] Partially filled, 3. [Incorrect] Heating elements are bent, 4. [Correct] Correctly laid stones.

ATTENTION! A sparsely filled stone container poses a fire hazard!

Safety Railings

A safety railing around the heater is recommended to prevent burns.

• You can build your own or purchase a special HUUM DROP safety railing.
• Materials with low thermal capacity and poor thermal conductivity (e.g., wood) are recommended.

ATTENTION! When using flammable materials for railings, strictly adhere to minimum safety distances between the heater and flammable structures.

Controlling the Heater

• Only use certified control panels designed for electric heaters.
• Heater output must be within the range specified by the control panel manufacturer.
• Follow the control device manufacturer's installation and operation manual.

Sauna Room Preparation

Wall Materials and Insulation

To ensure optimal heater performance and prevent overheating, insulate all heat-accumulating wall surfaces (glass, concrete, brick, plaster).

Sufficient Wall Insulation:

• Install a 2-4 in (50-100 mm) thick insulation layer (e.g., rigid foam boards with vapor barrier foil).
• Cover insulation with aluminum foil or reflective material, sealing joints with foil tape.
• Leave a 0.4 in (10 mm) ventilation gap between the moisture barrier and lining boards.
• Use 0.5-0.65 in (12-16 mm) thick wooden lining boards for finishing. Check wall for necessary cabling and reinforcements before mounting.
• Maintain a distance of at least 4 in (100 mm) between the floor and the board to prevent floor moisture.
• Ensure a minimum 0.2 in (5 mm) ventilation gap between wall and ceiling boards.
• Coat wooden surfaces with sauna wax or oil to protect them.

Ceiling of the Sauna Room

The recommended sauna room height is 82.7 - 90.6 in (2100 - 2300 mm). Lowering the ceiling in higher rooms reduces volume.

• The minimum permissible ceiling height for the HUUM DROP heater is 74.8 in (1900 mm).
• The distance between the top sauna bench step and the ceiling should be 43.5 - 51.2 in (1100 - 1300 mm).
• The ceiling should be insulated like the walls.

ATTENTION! When using heat protection materials (e.g., mineral tiles) on walls or ceilings, leave a sufficient ventilation gap. Direct tile installation can cause dangerous overheating.

ATTENTION! Verify with fire safety authorities about insulating firewall zones. Chimneys must not be insulated.

Darkening of Sauna Room Walls

Wooden walls may darken over time due to high temperatures, wood protection products, or fine stone dust. Following installation instructions prevents overheating of flammable materials.

ATTENTION! The maximum allowed temperature for wall and ceiling surfaces is 284°F (140°C).

Floor of the Sauna Room

Stone crumble and dust, washed by water, can damage plastic floors. Use ceramic tiles and dark joint filler under and around the heater to prevent aesthetic damage.

Ventilation of the Sauna

Efficient ventilation (six air exchanges per hour) is crucial for oxygen supply and fresh air.

Ventilation systems depend on natural or mechanical air inlets/outlets.

Sauna ventilation typically consists of:

• Supply air pipe: 2-4 in (50-100 mm) diameter.
• Exhaust air pipe: Twice the diameter of the supply pipe, 4-7.9 in (100-200 mm).
• Drying pipe: If no dedicated opening, the door can be left open for ventilation after use.

Mechanical Ventilation Setup:

1. Supply air pipe: Middle of heater or higher (≥ 15.7 in / 400 mm).
2. Exhaust air pipe: Opposite side of heater (≤ 23.6 in / 600 mm from floor).
3. Drying pipe opening: Opposite wall, under the ceiling.

Natural Ventilation Setup:

1. Supply air pipe: Middle of heater or higher (≥ 15.7 in / 400 mm).
2. Exhaust air pipe: Opposite wall, at least 7.9 in (20 cm) higher than supply air pipe (≤ 23.6 in / 600 mm from floor).
3. Drying pipe opening: Opposite wall, under the ceiling.

The supply air pipe should have an adjustable valve. If the exhaust air pipe is in the washroom, ensure a 4 in (100 mm) gap under the sauna door.

Use the drying pipe opening for post-sauna ventilation or to reduce humidity/stale air. Keep it closed during sauna use.

Using the Heater

ATTENTION! Before starting, check for foreign objects on, above, or near the heater to prevent fire hazards.

A suitable control system (not included) is required. Consult its manual.

Heating the Sauna Room

Initial use may produce odors from heating elements and stones; ventilate thoroughly. A properly insulated sauna with adequate heater capacity takes about one hour to reach desired temperature. Stones heat up concurrently.

Throwing Water on Heated Stones

To increase humidity, ladle water onto hot stones. Adjust frequency and amount to your preference.

• Pour water only on stones, not metal surfaces.
• Start ladling only when stones are fully heated and water evaporates completely.
• Use only clean, warm water.
• Ladle approximately 2.7 oz (80 ml) at a time. For more steam, wait a minute or two before ladling again.

ATTENTION! Never ladle water when someone is nearby, as hot steam can cause severe burns.

Warnings and Notes

• The heater is designed solely for heating sauna rooms to desired temperatures.
• Maintenance requiring special skills must be performed by a qualified professional.
• Always disconnect power before maintenance.
• Visually inspect the heater and sauna room before operation.
• The heater must be correctly filled with stones to operate.
• Do not cover the heater; this is a fire hazard.
• Do not touch a working heater to avoid burns.
• Insufficient sauna ventilation can dry out wood and cause fire hazards. Consult experts for ventilation planning.
• Never use a water hose to create steam.
• Use sauna fragrances and oils only diluted in steam water. Undiluted oils can ignite.
• A 2 in (50 mm) layer of fireproof thermal insulation is recommended under the sauna bench.
• For uninsulated saunas (e.g., barrel or outdoor), multiply the sauna volume by 1.5 to determine suitable heater output.
• Sauna doors must always open outward.
• Do not use the sauna for purposes other than intended.
• Do not leave small children unattended in the sauna.
• Sudden cooling after sauna is not recommended for those with poor health. Consult a doctor if necessary.
• Stay in the sauna only as long as it is comfortable.
• Keep this manual in a safe place.

Warranty Conditions

General:

• The purchaser must read and comply with the manual's requirements.
• Warranty is void if rules of use are not followed.
• Warranty is valid for material or manufacturing defects.
• Covers replacement of defective products or parts.
• Warranty period is 5 years from the date of purchase.

ATTENTION! Claims require presentation of purchase receipt/invoice and proof of intended use.

Warranty Terms:

• ATTENTION! Heating elements are considered expendable parts and are not covered.
• Normal wear and tear is not covered.
• Heater stones are not covered.

Warranty does not cover defects caused by:

• Transport and accidental damage.
• Improper storage, use, or overloading.
• Failure to comply with installation, operation, and safety instructions.

Warranty is not valid if:

• Repaired by unauthorized persons.
• Non-approved parts or unauthorized consumables were used.
• The product set is incomplete.

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