For the user and the qualified installer
1. Operating instructions
1.1 Unit description
The MTH hydraulically controlled open (pressureless) small-instantaneous water heater is designed for
supplying an open fitting with hot water. When the draw-off fitting is opened, the heating capacity
switches on automatically and the water is heated. The hot water output is dependent on the cold
water temperature, the heating capacity, and the flow rate.
1.2 The most important points in brief
Temperature adjustment is effected using the fitting:
– To increase the temperature, restrict the flow rate a little.
– For low temperatures, increase the flow rate or mix in cold water.
1.3 Hot water output
* The built-in automatic flow regulation provides for a constant flow rate. Hot water output with 230 V
mains voltage and a temperature increase of 25 K.
1.3 Important notes
In the case of temperature selection, water temperatures of over 60 °C can be reached at the hot
water outlet. Small children should therefore be kept away from the hot water outlets.
DANGER OF SCALDING!
• If the water feed of the MTH has been interrupted – e.g. because of the danger of frost or work on
the water pipe, the following steps must be taken before the unit is brought back into operation:
1. Remove or switch off fuses.
2. Open a tap downstream of the unit until the unit and the cold water feed pipe are free of air.
3. Replace or switch on fuses again.
• The small-instantaneous water heater must not be exposed to any pressure. Never close off the
fitting outlet and do not use an aerator or a hose with a jet regulator. Furring can close off the outlet
and thus cause the small-instantaneous water heater to be under pressure.
1.5 First actions to be taken in the event of malfunction
• Check the fuses
• Check the fitting for lime scale blockage or dirt accumulation.
See also "3. Fault finding by the user".
1.6 Maintenance and care
Maintenance work, such as for example checking the electrical safety, may only be carried out by
a qualified installer.
Regularly delime the jet regulator in the fitting and if necessary replace:
Order no.: 25 45 13
A damp cloth is sufficient for care of the unit. Do not use any abrasive or corrosive cleaning agents.
1.7 Operating and installation instructions
Keep these instructions carefully and pass them on to your successor in the event of a change in
ownership, in the event of maintenance and possible repair work they should be passed to the
qualified installer for his attention.
hot water output*