If you do not reach the temperature you want (or the stove does not get over 50°C), it is important to check that all resistors are heating (visible by their reddish colour).

If resistors are turned on, then the solution would be the quantity and arrangement of the lava stones. This has an important impact on the operation and performance of the stove.

Below are the guidelines for optimal operation, also available in the HARVIA manual:

• The diameter of the stones should be between 5 and 10cm.
• Only use split angular stones designed for use in a stove.
• Never use lightweight porous ceramic or soft soapstone "stones" in the stove.
• Dust stones before piling them in the stove.
• Do not fall stones into the stove.
• Do not wedge stones between the resistors.
• The stones should not be placed too tightly together, so as not to block the airflow through the stove.
• Stack stones in such a way that they support each other rather than resting on the resistors.
• Do not form a high stone pile on the stove.
• No objects that could alter the amount or airflow direction through the stove should be placed in or around the compartment where the stones are stored.