A boiler service visit works from the water side and the fire side together. The service professional checks system pressure and the expansion tank charge, inspects the pressure relief valve, verifies circulator pump operation, and looks for air binding in zones that are not producing heat.
Combustion follows: burner condition, ignition sequence, gas pressure, venting integrity, and a carbon monoxide screen. Aquastat settings, low water cutoff function, and zone valve or thermostat wiring get tested where the symptom points that way.
Because boilers are rare in the Temecula Valley, many of the units we see have gone years without a professional look, and sediment, corroded fittings, and drifted control settings are common findings. You get the diagnosis and the quoted price before the work begins, and approved repairs carry the Neighborly Done Right Promise®.