MONDEX Ahti Series User manual

INSTALLATION AND
OPERATING INSTRUCTIONS
Ahti and Ukko heaters
12/2017

2
Installation and Operating Instructions Ahti & Ukko
Contents
1 General safety instructions 3
2 Ahti and Ukko heaters 4
Heater components 5
3 Heater assembly and installation 6
Heater assembly 6
4 Technical specifications 8
Heater power and voltage 8
Heater dimensions and required quantity of stones 8
Minimum distances to inflammable material 8
Attachment points for heater installation 8
5 General instructions for users of Ahti and
Ukko heaters 9
Note 9
Installation cable 9
Additional connection options 9
6 Things to keep in mind when using the heater 9
Preheating 9
Sauna room 9
Temperature control 9
Heating time 10
Water thrown on heater 10
Sauna room structure 10
7 Wiring diagram 11
8 Time switch and thermostat operation 12
Additional connection options 12
9 Troubleshooting 13
Heater does not heat up 13
Warnings 13
Warranty 14
Maintenance; spare parts 14
Soapstone as a material 14
Changing the soapstone blocks 14
10 Service history 15

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Installation and Operating Instructions Ahti & Ukko
1. General safety information
Electrical connections may only be carried out by an electrician with valid installation
authorization according to the current regulations.
The Mondex electric heater is suitable for use in a family sauna, one (1) heater per sauna room.
Retain the installation and operating instructions for further reference.
Always check the adequacy of the fire protection distances!
Failure to observe the connection instructions may result in a risk of fire!
Always check the sauna room before switching the heater on!
Always check that the controller has switched the heater off after the set time period!
Due to the risk of fire, do not use the sauna to dry clothes or laundry.
Exercise caution with a hot heater, since the heater stones and metal parts become very hot
and can cause burns.
Steam from the heater is burning hot and may cause severe burns.
Children, disabled and ill persons who are using the sauna should be supervised.
Benches and floors may be slippery, therefore move in the sauna with caution.
Do not go to a hot sauna under the influence of narcotic substances (alcohol, drugs,
narcotics, etc.).
A stone compartment without stones or filled improperly will present a risk of fire!
Covering the heater will present a risk of fire.
Extended periods in a hot sauna will raise the temperature of the body, which may be dangerous.
This device is not intended for use by children or persons whose physical, sensory or mental
abilities or lack of experience and knowledge prevent them from using the device safely, without the
supervision of a person responsible for their safety or before they have been instructed on how to use
the device.
Children should be supervised to ensure that they do not play with the device.
This device complies with the requirements of:
Mondex pursues an active policy of product development and continuous improvement. For this
reason, Mondex reserves the right to make changes relating to the design and technical specifications
of their products without prior notice.
To ensure safe use of the sauna, please read these safety instructions first!

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Installation and Operating Instructions Ahti & Ukko
2. Ahti and Ukko heaters
Ahti heater.
6.0 kW and 8.0 kW.
Ukko heater.
6.0 kW, 8.0 kW and 10.5 kW.

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Installation and Operating Instructions Ahti & Ukko
min. 20 cm
2
3
7
10
4
5
12
11
1
5
6
8
12
13
9
Ahti and Ukko heater
components
1) Background stone
2) Small heater stones
3) Steel shelf
4) Side stone / stainless steel
5) Front and side bottom
stones / stainless steel
6) Overheating protector
reset switch
7) Thermostat
8) Time switch
9) Connection box
10) Heater blocks
11) Locking screws
12) Fastening screws
13) Junction box (min. of
20 cm from the heater)

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Installation and Operating Instructions Ahti & Ukko
Heater assembly
1) The package includes the heater, heater
blocks (a) and small heater stones (b).
Unpack the components with the box placed
horizontally (see Figures 3.1 and 3.2).
Inspect the heater components visually. If
you notice any discrepancies or deficiencies,
please contact the store where you purchased
the heater. Do not expose soapstone parts to
blows and denting when taking them out of
the package. The sauna’s floor surface should
also be properly protected before you begin
the installation.
2) Attach the heater to the wall with screws.
Observe the safety distances between the
heater and any inflammable material in
accordance with Table 4.4 (see Figure 3.3)
when installing the heater.
3) Install the heater blocks by aligning the
grooves on their sides with the rails on the
inside of the heater sides and lowering the
blocks carefully into place (see Figure 3.4).
The bevelled block should be placed topmost,
with the bevel facing up. Ensure that there is
a gap between the resistors and the heater
blocks (see Figure 3.5). If the bottom end of
any of the blocks is straight, place this block
at the bottom.
NOTE! Remove all plastic film before using
the heater!
3. Heater assembly and installation
Figure 3.1
Figure 3.2
a
b
Figure 3.4
Figure 3.3
Figure 3.5

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Installation and Operating Instructions Ahti & Ukko
4) Install the heater stone shelf: there are
metal fastening pins for the shelf, located
on the inside of the heater, approximately
9 cm downward from the upper end of the
air deflector. Insert the support arms of
the heater stone shelf in the rearmost pins
diagonally from the top (1) and turn the
shelf by the arms so that it rests on the front
fastening pins (2). After that, the heater
stones can be stacked on the shelf (see Figure
3.6).
5) Attach the background stone (see Figure 3.7).
6) When stacking the stones, ensure that you
do not place small heater stones among the
resistors or on top of the ventilation grill
located at the top edge of the heater (see
Figure 3.8).
After the assembly, remove all plastic films,
including those from behind the deflector.
Dents caused by the user or others are not
covered by Mondex’s warranty or other product
liability. When stacking the stones, be careful not
to dent the heater’s metal or painted surfaces to
avoid damaging them. For more information on
the warranty and replacing stones, see page 12.
Figure 3.7
Figure 3.8
.3
1
2
Figure 3.6

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Installation and Operating Instructions Ahti & Ukko
Type Power (kW) Voltage Connecting cable Fuse
Ahti, Ukko 6.0 6.0 400 V 3N 5 x 1.5 mm² 3 x 10 A
Ahti, Ukko 8.0 8.0 400 V 3N 5 x 2.5 mm² 3 x 16 A
Ukko 10.5 10.5 400 V 3N 5 x 2,5 mm² 3 x 16 A
4. Technical specifications
Table 4.1
Type Width (mm) Depth (mm) Height (mm) Stone amount (kg)
Ahti, Ukko 6.0 420 250 750 41
Ahti, Ukko 8.0 420 300 850 55
Ukko 10.5 500 350 970 70
Heater dimensions and required quantity of stones
Table 4.2
6.0 kW 8.0 kW 10.5 kW
A 220 220 365
B 310 310 435
C 275 275 310
D 140 206 260
E 615 615 780
F 103 130
Attachment points in corner installations
Table 4.5 Attachment points in corner installations (mm)
A
B C
E
F
D
Type A B C D E Volume
Ahti, Ukko 6.0 70 900 300 150 1900 5–8 m³
Ahti, Ukko 8.0 100 950 300 150 2100 7–10 m³
Ukko 10.5 70 990 200 150 2100 9–15 m³
Table 4.3 Minimum distances to inflammable material (mm)
Minimum distances to inflammable material
B
A
D
C
A
B
C
E
A
Attachment points
Type A B C
Ahti, Ukko 6.0 792 612 400
Ahti, Ukko 8.0 854 604 400
Ukko 10.5 976 776 470
Table 4.4 Attachment points (mm))

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Installation and Operating Instructions Ahti & Ukko
5. General instructions for users of Ahti and Ukko heaters
Note
Electrical connections may only be carried out by an electrician with valid installation authorization
according to the current regulations. The Ahti and Ukko electric heaters are suitable for use in a family
sauna, one (1) heater per sauna room. Retain the installation and operating instructions for further
reference.
Installation cable
Use rubber cable H07RN-F as a connection cable.
Additional connection options
Control of electric heating with the heater: The electric heating control cable is brought directly
to the heater’s junction box and further to the heater’s terminal block with a rubber cable that is
dimensionally identical to the incoming cable.
NOTE! Failure to observe the connection instructions may result in a risk of fire!
NOTE! Remove all plastic film before using the heater!
6. Things to keep in mind when using the heater
Preheating
Stack the heater stones according to the instructions. Before you start using the heater, you need to
preheat the heater two consecutive times (follow the same procedure also when the heater blocks are
replaced). In the first preheating, the heater will be heated for twenty minutes with the temperature
control set to the middle position. Let the heater cool down completely before the second, 40-minute
preheating session, in which the temperature control is set to the ¾ position. During preheating, the
resistors may emit fumes, so please ensure that the room is properly ventilated. Do not throw water
on the heater during preheating. Always monitor the preheating runs! If preheating is not carried out
in accordance with the instructions, the soapstone warranty will become void.
Sauna room
Always check the sauna room before switching the heater on! Always make sure that the timer has
switched the power off after the set time period!
Temperature control
The temperature is adjusted by means of a mechanical thermostat (see page 11). The actual heating
time depends on the dimensions, structure and thermal insulation of the sauna. The temperature
in the sauna room can be maintained at the desired level with the thermostat. If the temperature of
the sauna room becomes dangerously high for any reason, the overheating protector will switch the
heater’s power off. The cause of overheating must always be investigated. The power can be switched
on again by pressing the overheating protector reset button (see page 4, item 6).

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Installation and Operating Instructions Ahti & Ukko
Heating time
An excessive heating time consumes energy and does not improve the steaming properties. The best
steam is achieved by keeping the sauna’s heating time relatively short, at about 30–60 min., according
to the size of the sauna and the heater’s power. The size of the sauna, the glass door, windows, or
materials used may require a longer heating time.
Water thrown onto the heater
We recommend using hand warm water. The water should be fresh household water.
Sauna room structure
The sauna and its ceiling, in particular, should have good thermal insulation, as heat tends to escape
through the ceiling. Due to the moisture, we recommend that you use aluminium paper. The size of the
heater should be selected according to the size of the sauna (in cubic metres). In addition to calculating
the power need for the regular sauna structure (glass wool–foil–wood), the following should be taken
into consideration. If the sauna has any uninsulated wood, tile or concrete surfaces or the walls are
made of logs, the heater power needs to be increased. For every uninsulated square metre, the heater
power need increases by the same amount as if increasing the space volume by 1.2 m3 and on timber
surfaces by 1.5 m3. The factor for glass surfaces (glass walls, doors and uninsulated stone surfaces) is
also 1.2 m3 per square metre. In borderline cases, you should choose a heater with higher power.
The sauna needs efficient ventilation for a good oxygen level and a sufficient amount of fresh air.
The air in the sauna needs to change at least 6 times per hour. For a sauna with an electric heater,
mechanical ventilation is the most convenient ventilation method. The supply air should be provided
through an inlet located 500 mm, at a minimum, above the heater, either on the wall or in the ceiling.
The exhaust valve should be placed on the opposite wall, as far away from the heater and as close to
the floor level as possible. It is highly recommendable to install an exhaust air valve in the ceiling as
well for an easier removal of moisture after sauna sessions.
For more information, refer to the construction instructions and building regulations.

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Installation and Operating Instructions Ahti & Ukko
Heating control
Indicator “Heater on”
7. Wiring diagram

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Installation and Operating Instructions Ahti & Ukko
The time switch (4+8 h) is also the heater’s main switch. After a set time, the time switch automatically
switches the heater off. With the timer function, the heater can be set to switch on in 1–8 hours. The
maximum warm-up time is 4 hours.
For example:
If you want the sauna to be ready as soon as possible, set the time switch between 1 and 4. The
heater switches on immediately and begins to warm up. Set the desired temperature by turning the
thermostat.
If you want the sauna to be ready in three hours, turn the timer to 2 on the time switch scale of 1–8.
The timer starts and the power will be switched on and the heater will start warming up after two
hours. When the power has been switched on, the heater will remain on for a maximum of 4 hours.
After that, the power will be switched off automatically. You can switch the power off sooner by turning
the time switch to zero (0).
Always make sure that the time switch has switched the power off after the set time period!
8. Time switch and thermostat operation
Additional connection options
Connecting a signal light outside the sauna room
The connection cable used should be, for example, the H07RN-F cable with a cross-sectional area the
same as that of the connection cable.
Control of electric heating with the heater
The electric heating control cable is brought directly to the heater’s junction box and further to the
heater’s terminal block with a rubber cable that is dimensionally identical to the incoming cable.
Time switch
Overheat protector reset
switch
Thermostat

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Installation and Operating Instructions Ahti & Ukko
9. Troubleshooting
Heater does not warm up
Is the power on?
Has the overheating protector tripped?
> This is reset by pressing the overheating protector reset switch powerfully with a sharp object until
a click is heard.
The cause of overheating must always be determined before the heater is switched on again! If
necessary, contact the dealer or manufacturer.
Warnings
- Due to a risk of fire, do not use the sauna to dry clothes or laundry.
- Exercise caution with a hot heater, since the heater stones and metal parts become very hot and can
cause burns.
- The water steam rising from the heater is hot and can cause burns.
- Children, disabled and ill persons who are using the sauna should be supervised.
- Benches and floors may be slippery, therefore move in the sauna with caution.
- Do not go to a hot sauna under the influence of narcotic substances (alcohol, drugs, narcotics, etc.)

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Installation and Operating Instructions Ahti & Ukko
Warranty
For heaters and control units in private use, the warranty is two (2) years. In commercial/professional
use, the warranty is three (3) months. Commercial use refers to facilities in which the heater is in
use on a continuous basis, such as fitness centres, swimming pools, housing companies etc. It is not
recommended that the heater is on for longer than six (6) hours at a time. Retain the sales receipt or
warranty card. The warranty does not cover external or internal mechanical damage caused by, for
example, the impacts of stones or the heater falling over. The warranty also does not cover defects
caused by acts of nature, such as lighting or damage caused by overvoltage.
Maintenance, spare parts.
In case of a fault that cannot be solved, please contact the store where you purchased the heater or
email info@mondex.fi. Spare parts can be purchased from Mondex distributors and the manufacturer.
When purchasing spare parts, please refer to the name, power, serial number and manufacturing date
of the heater to ensure you receive the correct parts.
Soapstone as material
Small pebbles or pieces may come off the soapstones used in the heater. As this is not a failure of
the organic material but a natural feature that cannot be predicted at the time of manufacturing the
product, the manufacturer is not responsible for any damage. The heater blocks will become brittle,
change colour and may blister over the years, which indicates that they need to be changed. Any spots
of rust are due to the ferric oxide contained in soapstone. You may try to clean the stone surface with a
brass brush or a wet sanding paper.
Changing the soapstone blocks
Stack the heater stone according to the instructions. Before you start using the heater, you need to
preheat the heater two consecutive times (also when the heater blocks are replaced). In the first
preheating, the heater will be heated for twenty minutes with the temperature control set to the middle
position. Let the heater cool down completely before the second, 40-minute preheating session, in
which the temperature control is set to the ¾ position. During preheating, the resistors may emit
fumes. Therefore, ensure that the room is properly ventilated. Do not throw water on the heater during
preheating. Always monitor the preheating runs! If the preheating is not carried out in accordance with
the instructions, the soapstone warranty will become void.

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Installation and Operating Instructions Ahti & Ukko
10. Heater maintenance history
Date Procedure

Technical support: info@mondex.fi
Premec Oy
Kettukallionkatu 4
84100 Ylivieska, Finland
info@mondex.fi
www.mondex.fi