⚠ Safety note: This guide involves working with electricity, plumbing. If you're not completely sure about every step, stop and call a licensed professional. Before you start, always switch off the power at the breaker or close the main water/gas valve.
1 Prepare for safe work
Turn off the system at the controller, wait for the water and metal parts to cool, and read the manual for your specific model. If you smell gas, see smoke, or suspect an electrical fault, stop immediately and call a licensed service.
⚠ Warning: Heating elements and contactors operate at high electrical power. Internal measurements and component replacement must be performed by a trained professional.
2 Check controls and heating demand
Confirm winter mode, target temperature, and thermostat signal. Write down any error codes.
3 Check pressure and flow
On a cold system, read the pressure according to the allowed range and check that all available valves are open. Don’t refill without the manual.
4 Check external protections only
Visually check that the appropriate protection is off. If it trips again, don’t try turning it on repeatedly.
? Tip: Take a photo of the initial state and change only one thing at a time. That way you’ll know which check actually affected the problem.
5 Reassemble, test, and set limits
Return settings one by one and monitor temperature, pressure, sound, and any possible leaks. If values don’t stabilize or the alarm repeats, leave the system off and request professional diagnostics.
When to call a professional: If the job involves changes to the electrical panel, the main gas line, or load-bearing walls/beams — or if you're not sure how it will turn out — this is not a DIY task. Hire a licensed professional.