Cut off power heater supply before your intervention
Open the protective cover
Tighten all the electrical wires
If you note any signs of leaks and if there is a presence of water, you may have to replace some defective parts
Close the protective cover
About the hydraulic safety group cheking
The boiler manufacturers suggest to operate the hydraulic safety group valve and the ball valve manually once a month
A hydraulic safety group should only running water when the hydraulic safety group is heating. If the hydraulic safety group leaks while not heating you must replace it. To help you, you can watch the video "How to replace a hydraulic safety group"
Don’t forget to turn on the power heater supply
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